ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes

ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes Süleyman Gökalp Güneş, Barış Gülmez, Beniz İrem Ersoy Şığva, Yusuf Kahya, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8569383/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Apr, 2026 Read the published version in BMC Pulmonary Medicine → Version 1 posted 14 You are reading this latest preprint version Abstract Background First described in the early 19th century as “simple pneumothorax,” primary spontaneous pneumothorax (PSP) refers to the presence of air within the pleural cavity without an identifiable secondary cause. PSP predominantly affects males, smokers, tall individuals, and those with a low body mass index. However, the occurrence of PSP in individuals without these classical risk factors, as well as variability among patients with similar phenotypes, suggests that additional pathophysiological mechanisms may contribute to disease susceptibility. Although ABO and Rh blood group variations have been associated with several pulmonary and systemic diseases, data regarding their relationship with PSP remain limited. Objective This study aimed to evaluate whether ABO and Rh blood group subtypes are associated with PSP by analyzing a homogeneous surgical patient cohort from two cities with distinct altitudes and comparing the findings with national blood group distribution. Methods A total of 174 patients who underwent surgery for PSP between 2021 and 2024 were retrospectively reviewed from two centers located in geographically distinct altitude regions. ABO and Rh distributions were analyzed using Pearson’s chi-square test, inverse probability of treatment weighting (IPTW), and one-sample Z testing. Results Compared with national data, PSP patients showed an overrepresentation of blood group A, an underrepresentation of blood group O, and a lower prevalence of Rh positivity. Primary spontaneous pneumothorax Blood type ABO Rh Figures Figure 1 Introduction Primary spontaneous pneumothorax (PSP), historically referred to as "simple pneumothorax" in the early 19th century, is defined today as the presence of air in the pleural cavity without an apparent secondary cause such as trauma, iatrogenic intervention, or an underlying pulmonary disease. It predominantly occurs in individuals with a distinct phenotype characterized by low body mass index (BMI), cigarette smoking, tall stature, and male sex [ 1 ]. PSP typically results from air leakage into the pleural space due to the spontaneous rupture of bullae or blebs formed under high intrathoracic distending pressures. In addition to phenotypic predisposition, several etiologic factors have been implicated, including inflammation, tobacco use, air pollution (e.g., NO₂ and PM10), air leakage from thinned visceral pleura (pleural porosity), abnormal pulmonary elasticity, and familial susceptibility [ 1 – 3 ]. Moreover, certain systemic conditions such as Marfan syndrome, homocystinuria, thoracic endometriosis, Birt–Hogg–Dubé syndrome, and anorexia nervosa are recognized risk factors for PSP. The reported incidence of PSP varies by region, influenced by environmental and demographic factors such as atmospheric pressure, altitude, and patient phenotype. For instance, the incidence has been reported as 24 per 100,000 in men and 9.8 per 100,000 in women in the United Kingdom, and approximately 4.2 per 100,000 in the United States, with a male-to-female ratio of 3.3 [ 4 , 5 ]. Tobacco use significantly increases the risk of PSP, by 4–7 times in light smokers and up to 100 times in heavy smokers. The recurrence rate within one year following a PSP event ranges from 25% to 50% [ 5 , 6 ]. Established predisposing factors include male sex, young age, tobacco use, radiologic presence of bullae, low BMI, connective tissue disorders, genetic mutations (e.g. FLCN), previous history of pneumothorax, and changes in atmospheric pressure [ 7 , 8 ]. However, the observation that PSP can also occur among individuals lacking these risk factors suggests the involvement of additional pathophysiological mechanisms. Among respiratory diseases, variations in blood group antigens and Rh factor have been associated with disease susceptibility, yet data specific to PSP are limited. This knowledge gap necessitated an investigation into the potential association between ABO and Rh blood group variability and PSP. Objective This study aimed to investigate the association between ABO blood group subtypes, Rh factor, and PSP by comparing a homogeneous patient cohort from two cities with differing altitudes and national blood group distribution data. Materials and Methods A total of 174 patients who underwent surgery for PSP between 2021 and 2024 were retrospectively reviewed from two centers located in geographically distinct cities with different altitudes. Considering regional differences, patients were evaluated separately in terms of age, sex, preoperative hemoglobin levels, tobacco use, history of chronic disease, surgical procedures performed, duration of intensive care unit (ICU) and hospital stay, and postoperative complications. These variables were compared between the two cities. ABO blood groups and Rh factor subtypes were assessed comparatively between the cities and against nationwide population data. Patients aged ≥18 years who underwent surgical treatment for PSP either video-assisted thoracoscopic surgery (VATS) or thoracotomy involving wedge resection and parietal pleurectomy—were included in the study (Figure 1A–D). Patients diagnosed with recurrent pneumothorax, secondary spontaneous pneumothorax, or those treated with non-surgical approaches (such as observation with nasal oxygen therapy or tube thoracostomy) were excluded from the study. All patients included underwent routine blood group testing during the standard preoperative preparation phase; therefore, no additional blood group analysis was required for this study. Statistical Analysis All statistical analyses were performed using IBM SPSS Statistics (v25.0, IBM Corp. Armonk, NY) and Microsoft Excel (v365). Descriptive statistics (mean, standard deviation, proportions, and percentages) were used to summarize baseline data. The observed Rh-positivity rate in the study population was compared with the nationwide reported rate using a one-sample proportion Z-test. Additionally, the distribution of each ABO blood group (A, O, B, AB) was individually compared to national data using independent proportion Z-tests. To assess potential differences in blood group and Rh factor distributions between the two geographically distinct regions, the Inverse Probability of Treatment Weighting (IPTW) method was applied to minimize the influence of confounding variables. The propensity score model included age, sex, smoking history, and comorbidity status. Stabilized weights were applied to reduce variance inflation. The overall ABO blood group distribution in the study cohort was also compared with the expected distribution based on Ministry of Health data and relevant literature. A Pearson Chi-square test was used to assess the significance of differences between observed and expected frequencies. Given the exploratory nature of subgroup analyses, no formal correction for multiple comparisons was applied. A post-hoc power analysis was performed to evaluate whether the sample size (n=194) was sufficient to detect a significant difference in ABO and Rh blood group distributions between the PSP patient group and the general population. Based on a one-sample proportion Z-test, considering the national Rh(+) prevalence of 84.9% and the observed proportion of 72.7% in the PSP group, with a two-sided alpha of 0.05, the achieved power was calculated to be >99%. This suggests that the study was adequately powered to detect statistically significant differences in Rh distribution. For ABO blood group comparisons, assuming an effect size (Cohen's w) of approximately 0.2 (small to medium effect), a Chi-square goodness-of-fit test with 4 degrees of freedom and a sample size of 194 yields a power of approximately 80%, indicating sufficient sensitivity to detect moderate deviations from expected ABO distributions. Chi-square tests were used to evaluate overall distribution differences, while Z-tests were applied to explore individual blood group proportion deviations Findings A total of 174 patients who underwent surgical treatment for PSP between 2021 and 2024 were retrospectively analyzed from two centers located in geographically distinct cities with differing altitudes: Van (V) at 1,726 meters and Ankara (A) at 938 meters. Of these, 90 patients were from V and 84 from A. As expected, the majority of patients were male (male: n=141, female n=33), though the gender difference was not statistically significant (p > 0.05). The mean age differed significantly between the two cities; 31.4 years (range: 18–75) in V and 29.8 years (range: 18–70) in A (p = 0.001). Non-pulmonary comorbidities were more common among patients in V (p = 0.001). The prevalence of tobacco use was high in both groups, without a significant intergroup difference (p > 0.05). Video-assisted thoracoscopic surgery (VATS) was the preferred approach in both centers. In V, thoracotomy was performed in 3 patients due to dense pleural adhesions (p > 0.05). The postoperative hospital stay was shorter in A, potentially attributable to differences in surgical capacity (number of operating rooms) and higher comorbidity burden in V (p = 0.001). Postoperative ICU stay was approximately 1 day in both groups but showed a statistically significant difference (p = 0.029). Preoperative hemoglobin (Hgb) levels were significantly higher in patients from V (p = 0.003), which may be related to high altitude–induced compensatory erythrocytosis. The most frequently observed postoperative complications were atelectasis, pneumonia, and prolonged air leak, with significantly higher rates in A (p = 0.001). Regarding blood group distribution, blood group A was most common and AB least common in V, while both A and O were most frequent in A, with AB again the least observed (p = 0.008). Rh positivity was more prevalent in both groups, without a statistically significant difference between centers (p > 0.05) (Table 1). Table 1: Comparative demographics and outcomes of patients by city of admission. (Continuous variables were analyzed using the Mann–Whitney U test. Categorical variables were compared using the Chi-square test or Fisher’s exact test, where applicable.) Variable Total (N- %) Van (N- %) Ankara (N- %) P value Primary spontaneous pneumothorax 174 90 84 >0.05 Age 31.4 (18-75) 29.8( 18-70) 33.0( 19-75) 0.001 Female Male 33 (18.9) 141 (81) 14 (15.6) 76 (84.4) 19 (22.6) 65 (77.4) >0.05 Co-morbidity (+) (-) 36 (20.7) 138 (79.3) 7 (7.8) 83 (92.2) 29 (34.5) 55 (65.5) 0.001 Smoking history (+) (-) 104 (59.8) 64 (36.8) 61 (67.8) 29 (32.2) 43 (51.2) 35 (41.7) >0.05 VATS Thoracotomy 171 (98.3) 3 (1.7) 87 (96.7) 3 (3.3) 84 (100) 0 (0) >0.05 Length of hospital stay (day) 6.9 (3-18) 8.23 (3-18) 5.5( 4-12) 0.001 Length of ICU stay (day) 0.97 (0-1) 0.94 (0-1) 1 (1) 0.029 Preoperative Hgb (g/dL) 14.6 (9.6-18.3) 15.0 (10.3-18.3) 14.3 (9.6-17.6) 0.003 Postoperative complication (+) (-) 51 (29.3) 123 (70.7) 11 (12.2) 79 (87.8) 40 (47.6) 44 (52.4) 0.001 Blood type 0 A B AB 174 47 (27.0) 81 (46.6) 32 (18.4) 14 (8.0) 90 15 (16.7) 49 (54.4) 20 (22.2) 6 (6.7) 84 32 (38.1) 32 (38.1) 12 (14.3) 8 (9.5) 0.008 Rh (+) Rh (-) 141 (81.0) 33 (19.0) 76 (84.4) 14 (15.6) 65 (77.4) 19 (22.6) >0.05 When the ABO blood group distribution observed in this study was compared to the national distribution, no significant difference was found using the Chi-square test (χ² = 3.98, p = 0.264). However, when expected frequencies based on large-scale national studies were used (n = 174; A: 73.08, O: 59.16, B: 27.84, AB: 13.92), the Chi-square goodness-of-fit test revealed a statistically significant difference (χ² = 6.21, df = 3, p = 0.045). This suggests that the distribution of blood groups among PSP patients deviates significantly from that of the general population (p < 0.05) (Table 2). Table 2: Observed and expected frequencies of ABO blood groups were calculated using a national reference distribution, standardized to the study population (n = 174). Blood Type Observed (n) Expected (Nationwide) (n) A 81 73.08 0 47 59.16 B 32 27.84 AB 14 13.92 In order to balance non-homogeneous groups between the two cities, an IPTW analysis was performed. This evaluation revealed no statistically significant differences in ABO blood group or Rh factor distributions between the two centers (p = 0.999 and p = 0.780, respectively) (Table 3). Table 3: Using the Inverse Probability of Treatment Weighting (IPTW) method, balanced means of blood group and Rh positivity rates were compared between the cities of V and A. The analysis revealed no statistically significant differences in either variable between the two groups. Blood type was numerically encoded for analytical purposes. Variable V (mean) A (mean) P value (IPTW) Blood Type (encoded) 1.509 1.509 0.99 RH (positivity rate) 0.825 0.813 0.78 To compare proportions between the national population and the study cohort, a one-sample Z-test was conducted. While the national Rh positivity rate is reported as 84.9%, the rate among PSP patients in our study was found to be 72.7% [9,10]. This difference was statistically significant (Z = -4.80, p < 0.001), supporting the hypothesis that Rh-negative individuals may have a predisposition to pneumothorax. However, this observation does not establish a causal relationship. When a similar Z-test was applied to ABO blood groups, no statistically significant differences were observed between the study population and national data (Table 4). Table 4: A comparison of the sample proportions of each blood group observed in the study with the expected national proportions using the Z-test. Blood Type Sample Rate Nationwide rate Z test P value A 0.466 0.42 1.204 0.22 0 0.270 0.34 -2.076 0.03 B 0.184 0.16 0.814 0.41 AB 0.080 0.08 0.022 0.98 Discussion In this study, we aimed to evaluate factors potentially associated with PSP in patients who underwent surgery in two cities with differing atmospheric pressures, and to explore whether ABO blood group and Rh factor show differential distribution patterns within a homogeneous patient population. The age difference observed between the two cities was attributed to the earlier onset and wider prevalence of tobacco use in city V (p = 0.001) [ 11 ]. Comorbid conditions, excluding chronic lung diseases, were more common among patients operated in city A, which may be explained by its status as a university hospital that attracts more complex cases (p = 0.001). Consequently, postoperative complications were significantly higher in city A (p = 0.001). The significantly longer perioperative hospital stay in city V was attributed to limited surgical table availability in that center (p = 0.001). Preoperative Hgb levels were significantly higher in city V, likely due to secondary polycythemia associated with the city’s high altitude (p = 0.003). Our study revealed statistically significant differences in both ABO blood group distribution and Rh factor between the study population and the national averages (p = 0.008). Among the 174 patients with PSP, 72.7% were Rh-positive, compared to the national prevalence of 84.9%. A one-sample Z-test demonstrated a significantly lower Rh-positivity rate in our PSP cohort (Z = -4.81, p < 0.001), suggesting a possible predisposition to pneumothorax among Rh-negative individuals. Furthermore, the overrepresentation of Rh-negative individuals and blood group A in the PSP population suggests a potential association with PSP rather than a causal relationship. These differences remained statistically significant across multiple analytical methods, including Chi-square and Z-tests, and persisted even after adjustment for potential confounding factors using Inverse IPTW. To reduce the potential heterogeneity between centers, we applied IPTW, balancing confounders such as age, sex, and smoking history. The persistence of disparities in blood group distribution after IPTW suggests that this finding is not merely due to geographic or demographic variability. A national-level goodness-of-fit Chi-square test also revealed a statistically significant difference between observed and expected blood group distributions (χ² = 6.21, p = 0.045), driven primarily by the overrepresentation of blood group A and underrepresentation of blood group O. This observation supports the hypothesis that blood group A may be a predisposing factor for PSP. Conversely, blood group O was significantly underrepresented among PSP patients compared to the general population (p = 0.03). This finding may indicate that blood group O is less frequently observed among PSP patients, suggesting a possible inverse association. However, the underrepresentation of blood group O does not confirm a direct protective role; rather, it indicates a statistical association. Causal inference would require exploration of the underlying biological mechanisms. Additionally, potential confounders such as age, sex, smoking, and comorbidities may be linked to blood group O. Nonetheless, the robustness of our finding is enhanced by adjustment using IPTW. However, the absence of a healthy control group limits the strength of evidence. When the ABO blood group distribution of PSP patients was compared between the two centers (Table 2 ), no statistically significant difference was observed (p = 0.264). However, when compared with the national blood group distribution, significant deviations were identified among the patient group (p = 0.045). This suggests that the observed differences in blood group distribution in our study may be related to the development of PSP rather than geographic variations. In other words, there is no significant difference between the patients from V and A; however, the combined patient population shows a deviation from the healthy national population. There is growing interest in the literature regarding the association between blood types and respiratory diseases. Blood group A has been frequently reported in conditions such as pulmonary embolism, COVID-19, and emphysema, whereas blood group O has been associated with a lower risk of deep vein thrombosis and pulmonary embolism [ 12 – 14 ]. However, studies directly evaluating the relationship between blood type and spontaneous pneumothorax remain scarce. From this perspective, our study contributes novel data to the existing literature. PSP has been suggested to have a genetic component [ 7 , 8 ], and our study explored its possible correlation with ABO and Rh blood group systems. Similar associations have been established between blood groups and other respiratory conditions such as emphysema, chronic obstructive pulmonary disease (COPD), asthma, and small cell lung cancer [ 15 – 20 ]. In a study by Sahinoglu et al., investigating the relationship between PSP, blood group, and ambient temperature, it was hypothesized that the absence of A and B antigens in blood group O may lead to a different inflammatory response under thermal stress [ 21 ]. Conclusion In this study, the distribution of ABO blood groups and Rh factor among patients diagnosed with PSP was compared with national population data, revealing statistically significant differences. Compared with the general population, PSP patients demonstrated a distinct distribution of ABO blood groups and Rh factor, characterized by a higher prevalence of blood group A, a lower prevalence of blood group O, and reduced Rh positivity. Study Limitations However, this study has certain limitations. Firstly, all participants included had PSP, and thus a direct comparison with a healthy control group was not possible. Nonetheless, since the national blood group distribution was derived from robust population-level data, the comparisons remain valid. Secondly, a larger sample size and future prospective studies are needed to validate and expand upon these findings. Abbreviations PSP Primary spontaneous pneumothorax BMI Body mass index FLCN Folliculin VATS Video assisted thoracoscopic surgery IPTW Inverse Probability of Treatment Weighting V Van A Ankara Hgb Hemoglobine ICU Intensive care unit Declarations Ethical Approval: All procedures involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was approved by the Ethics Committee of Ankara University Faculty of Medicine (approval number: 20055001036-3; registration number: 2025/1036; approval date: 07 January 2026). Due to the retrospective design of the study, the requirement for informed consent was waived by the Ethics Committee. Clinical trial number: not applicable. Consent for publication: All authors provided consent for publication. The consent form was signed by the relevant authors. The patient provided written informed consent for the publication of personal or clinical details, along with any identifying images included in this study. Availability of data and materials: The data and materials are available for use by the publisher. The datasets used and/or analyzed in the present study can be obtained from the corresponding author upon reasonable request. Competing Interests: The author declares that there are no potential conflicts of interest. This article is protected by copyright. All rights reserved. Funding: The authors declare there is no financial support for this study. Author contributions: Concept (SGG,BG,YK,İA,AK,ES,SD), Design (BG,BİES,YK,AK,ES,BMY), Data Collection and/or Processing (SGG,BG,BIES,İA,AK,SD,BMY), Analysis and/or Interpretation (SGG,KS,BİES,YK,İA,ES,SD,BMY) Acknowledgement: We extend our sincere gratitude to all the authors who contributed to this study. We extend our respects to the editorial team and the esteemed referees who evaluated the work. References Hallifax R. Aetiology of primary spontaneous pneumothorax. J Clin Med. 2022;11:490. doi:10.3390/jcm11030490 Canavar A, Erk M, Seyrek Y, et al. Do atmospheric pressure and air pollution affect the incidence of primary spontaneous pneumothorax? Curr Thorac Surg. 2024;9. doi:10.26663/cts.2024.015 Haberal MA, Akar E, Şengören Dikiş Ö, Özkaya M, Ay MO, Kaya H, Yüksel M. Effects of atmospheric changes on spontaneous pneumothorax. Eurasian J Emerg Med. 2022;21(3). Huan NC, Sidhu C, Thomas R. Pneumothorax: classification and etiology. 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Supplementary Files graphicabstract.tiff Cite Share Download PDF Status: Published Journal Publication published 25 Apr, 2026 Read the published version in BMC Pulmonary Medicine → Version 1 posted Editorial decision: Revision requested 02 Mar, 2026 Reviews received at journal 28 Feb, 2026 Reviewers agreed at journal 19 Feb, 2026 Reviews received at journal 13 Feb, 2026 Reviews received at journal 09 Feb, 2026 Reviewers agreed at journal 03 Feb, 2026 Reviews received at journal 30 Jan, 2026 Reviewers agreed at journal 29 Jan, 2026 Reviewers agreed at journal 29 Jan, 2026 Reviewers invited by journal 29 Jan, 2026 Editor invited by journal 16 Jan, 2026 Editor assigned by journal 13 Jan, 2026 Submission checks completed at journal 13 Jan, 2026 First submitted to journal 10 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8569383","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":588014633,"identity":"55e4f9b9-5e71-4931-ba63-4fea856f8b0b","order_by":0,"name":"Süleyman Gökalp Güneş","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYFACNgaGB2AG8wEGxgZitSRAGAkka+ExIE6LvHtb4oeEX4fz+PnPfJP4ucNGjoH98NEN+LQYnjl2WCKx73Cx5IzcbZK9Z9KMGXjS0m7g1TIjvUEisedw4oYbvNskeNsOJzZI8JgR0tL8A6Rl//kzzyT/EqNFXiLtmETCD6AtDDls0kTZYsBzLM0isSE9ccaNNGNr2bY0YzZCfpFvbzO+8eGPdWJ//+GHN9+22cjxsx8+ht+WA0CCsQ3MZpEAkWz4lINtaQCRf8Bs5g+EVI+CUTAKRsHIBAD9iFHrcJy1zwAAAABJRU5ErkJggg==","orcid":"","institution":"Ankara University","correspondingAuthor":true,"prefix":"","firstName":"Süleyman","middleName":"Gökalp","lastName":"Güneş","suffix":""},{"id":588014634,"identity":"3ac089e9-94f3-4871-98b4-d02881469c2a","order_by":1,"name":"Barış Gülmez","email":"","orcid":"","institution":"İzmir City Hospital","correspondingAuthor":false,"prefix":"","firstName":"Barış","middleName":"","lastName":"Gülmez","suffix":""},{"id":588014635,"identity":"15dfc473-7541-4d68-ad29-95edc52c97eb","order_by":2,"name":"Beniz İrem Ersoy Şığva","email":"","orcid":"","institution":"SBÜ. Van Training and Research Hospital","correspondingAuthor":false,"prefix":"","firstName":"Beniz","middleName":"İrem Ersoy","lastName":"Şığva","suffix":""},{"id":588014636,"identity":"4b009eda-8c7d-44e1-9426-0edccbd39523","order_by":3,"name":"Yusuf Kahya","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"Yusuf","middleName":"","lastName":"Kahya","suffix":""},{"id":588014637,"identity":"a86fb558-70df-4ffe-a57e-72f2ad8b52f0","order_by":4,"name":"İslam Aktürk","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"İslam","middleName":"","lastName":"Aktürk","suffix":""},{"id":588014638,"identity":"08945912-252e-47d1-815f-99be7bc030c6","order_by":5,"name":"Aleyna Kılıç","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"Aleyna","middleName":"","lastName":"Kılıç","suffix":""},{"id":588014639,"identity":"4b3b4b28-90c2-40f3-9871-7ee40359195a","order_by":6,"name":"Ethar Shumar","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"Ethar","middleName":"","lastName":"Shumar","suffix":""},{"id":588014640,"identity":"96f074af-e317-414f-aea9-5e0e60f80e45","order_by":7,"name":"Şebnem Dursun","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"Şebnem","middleName":"","lastName":"Dursun","suffix":""},{"id":588014641,"identity":"6cfa426f-f6c0-4d82-a0a5-6f4a2b548f19","order_by":8,"name":"Bülent Mustafa Yenigün","email":"","orcid":"","institution":"Ankara University","correspondingAuthor":false,"prefix":"","firstName":"Bülent","middleName":"Mustafa","lastName":"Yenigün","suffix":""}],"badges":[],"createdAt":"2026-01-10 15:54:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8569383/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8569383/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12890-026-04303-1","type":"published","date":"2026-04-25T15:59:50+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":102310221,"identity":"db9b8e45-161a-4dfa-afb3-a5618c919c0b","added_by":"auto","created_at":"2026-02-10 11:52:59","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":455046,"visible":true,"origin":"","legend":"A:Intraoperative view of multiple bullae. B\u0026ndash;C: Resected specimens. D: Parietal pleurectomy in progress.","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8569383/v1/2500523e187c833136e950ee.png"},{"id":107928712,"identity":"2bbc7905-ceec-40e2-9ddf-010dcdbcfd50","added_by":"auto","created_at":"2026-04-27 16:12:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":863385,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8569383/v1/991abeb2-41f0-4d7c-9987-4f006a513974.pdf"},{"id":102310285,"identity":"d51da8fb-e5cb-4787-8c7b-5fbb97fc058c","added_by":"auto","created_at":"2026-02-10 11:53:08","extension":"tiff","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":1256832,"visible":true,"origin":"","legend":"","description":"","filename":"graphicabstract.tiff","url":"https://assets-eu.researchsquare.com/files/rs-8569383/v1/11ebc88936b278a85ca27430.tiff"}],"financialInterests":"No competing interests reported.","formattedTitle":"ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePrimary spontaneous pneumothorax (PSP), historically referred to as \"simple pneumothorax\" in the early 19th century, is defined today as the presence of air in the pleural cavity without an apparent secondary cause such as trauma, iatrogenic intervention, or an underlying pulmonary disease. It predominantly occurs in individuals with a distinct phenotype characterized by low body mass index (BMI), cigarette smoking, tall stature, and male sex [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. PSP typically results from air leakage into the pleural space due to the spontaneous rupture of bullae or blebs formed under high intrathoracic distending pressures. In addition to phenotypic predisposition, several etiologic factors have been implicated, including inflammation, tobacco use, air pollution (e.g., NO₂ and PM10), air leakage from thinned visceral pleura (pleural porosity), abnormal pulmonary elasticity, and familial susceptibility [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Moreover, certain systemic conditions such as Marfan syndrome, homocystinuria, thoracic endometriosis, Birt\u0026ndash;Hogg\u0026ndash;Dub\u0026eacute; syndrome, and anorexia nervosa are recognized risk factors for PSP.\u003c/p\u003e \u003cp\u003eThe reported incidence of PSP varies by region, influenced by environmental and demographic factors such as atmospheric pressure, altitude, and patient phenotype. For instance, the incidence has been reported as 24 per 100,000 in men and 9.8 per 100,000 in women in the United Kingdom, and approximately 4.2 per 100,000 in the United States, with a male-to-female ratio of 3.3 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Tobacco use significantly increases the risk of PSP, by 4\u0026ndash;7 times in light smokers and up to 100 times in heavy smokers. The recurrence rate within one year following a PSP event ranges from 25% to 50% [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eEstablished predisposing factors include male sex, young age, tobacco use, radiologic presence of bullae, low BMI, connective tissue disorders, genetic mutations (e.g. FLCN), previous history of pneumothorax, and changes in atmospheric pressure [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, the observation that PSP can also occur among individuals lacking these risk factors suggests the involvement of additional pathophysiological mechanisms. Among respiratory diseases, variations in blood group antigens and Rh factor have been associated with disease susceptibility, yet data specific to PSP are limited. This knowledge gap necessitated an investigation into the potential association between ABO and Rh blood group variability and PSP.\u003c/p\u003e\n\u003ch3\u003eObjective\u003c/h3\u003e\n\u003cp\u003eThis study aimed to investigate the association between ABO blood group subtypes, Rh factor, and PSP by comparing a homogeneous patient cohort from two cities with differing altitudes and national blood group distribution data.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eA total of 174 patients who underwent surgery for PSP between 2021 and 2024 were retrospectively reviewed from two centers located in geographically distinct cities with different altitudes. Considering regional differences, patients were evaluated separately in terms of age, sex, preoperative hemoglobin levels, tobacco use, history of chronic disease, surgical procedures performed, duration of intensive care unit (ICU) and hospital stay, and postoperative complications. These variables were compared between the two cities. ABO blood groups and Rh factor subtypes were assessed comparatively between the cities and against nationwide population data.\u003c/p\u003e\n\u003cp\u003ePatients aged \u0026ge;18 years who underwent surgical treatment for PSP either video-assisted thoracoscopic surgery (VATS) or thoracotomy involving wedge resection and parietal pleurectomy\u0026mdash;were included in the study (Figure 1A\u0026ndash;D).\u003c/p\u003e\n\u003cp\u003ePatients diagnosed with recurrent pneumothorax, secondary spontaneous pneumothorax, or those treated with non-surgical approaches (such as observation with nasal oxygen therapy or tube thoracostomy) were excluded from the study. All patients included underwent routine blood group testing during the standard preoperative preparation phase; therefore, no additional blood group analysis was required for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll statistical analyses were performed using IBM SPSS Statistics (v25.0, IBM Corp. Armonk, NY) and Microsoft Excel (v365). Descriptive statistics (mean, standard deviation, proportions, and percentages) were used to summarize baseline data. The observed Rh-positivity rate in the study population was compared with the nationwide reported rate using a one-sample proportion Z-test. Additionally, the distribution of each ABO blood group (A, O, B, AB) was individually compared to national data using independent proportion Z-tests. To assess potential differences in blood group and Rh factor distributions between the two geographically distinct regions, the Inverse Probability of Treatment Weighting (IPTW) method was applied to minimize the influence of confounding variables. The propensity score model included age, sex, smoking history, and comorbidity status. Stabilized weights were applied to reduce variance inflation. The overall ABO blood group distribution in the study cohort was also compared with the expected distribution based on Ministry of Health data and relevant literature. A Pearson Chi-square test was used to assess the significance of differences between observed and expected frequencies.\u0026nbsp;Given the exploratory nature of subgroup analyses, no formal correction for multiple comparisons was applied.\u003c/p\u003e\n\u003cp\u003eA post-hoc power analysis was performed to evaluate whether the sample size (n=194) was sufficient to detect a significant difference in ABO and Rh blood group distributions between the PSP patient group and the general population. Based on a one-sample proportion Z-test, considering the national Rh(+) prevalence of 84.9% and the observed proportion of 72.7% in the PSP group, with a two-sided alpha of 0.05, the achieved power was calculated to be \u0026gt;99%. This suggests that the study was adequately powered to detect statistically significant differences in Rh distribution.\u003c/p\u003e\n\u003cp\u003eFor ABO blood group comparisons, assuming an effect size (Cohen\u0026apos;s w) of approximately 0.2 (small to medium effect), a Chi-square goodness-of-fit test with 4 degrees of freedom and a sample size of 194 yields a power of approximately 80%, indicating sufficient sensitivity to detect moderate deviations from expected ABO distributions.\u0026nbsp;Chi-square tests were used to evaluate overall distribution differences, while Z-tests were applied to explore individual blood group proportion deviations\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFindings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 174 patients who underwent surgical treatment for PSP between 2021 and 2024 were retrospectively analyzed from two centers located in geographically distinct cities with differing altitudes: Van (V) at 1,726 meters and Ankara (A) at 938 meters. Of these, 90 patients were from V and 84 from A. As expected, the majority of patients were male (male: n=141, female n=33), though the gender difference was not statistically significant (p \u0026gt; 0.05). The mean age differed significantly between the two cities; 31.4 years (range: 18\u0026ndash;75) in V and 29.8 years (range: 18\u0026ndash;70) in A (p = 0.001). Non-pulmonary comorbidities were more common among patients in V (p = 0.001). The prevalence of tobacco use was high in both groups, without a significant intergroup difference (p \u0026gt; 0.05). Video-assisted thoracoscopic surgery (VATS) was the preferred approach in both centers. In V, thoracotomy was performed in 3 patients due to dense pleural adhesions (p \u0026gt; 0.05). The postoperative hospital stay was shorter in A, potentially attributable to differences in surgical capacity (number of operating rooms) and higher comorbidity burden in V (p = 0.001). Postoperative ICU stay was approximately 1 day in both groups but showed a statistically significant difference (p = 0.029).\u003c/p\u003e\n\u003cp\u003ePreoperative hemoglobin (Hgb) levels were significantly higher in patients from V (p = 0.003), which may be related to high altitude\u0026ndash;induced compensatory erythrocytosis. The most frequently observed postoperative complications were atelectasis, pneumonia, and prolonged air leak, with significantly higher rates in A (p = 0.001). Regarding blood group distribution, blood group A was most common and AB least common in V, while both A and O were most frequent in A, with AB again the least observed (p = 0.008). Rh positivity was more prevalent in both groups, without a statistically significant difference between centers (p \u0026gt; 0.05) (Table 1).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eTable 1:\u003c/strong\u003e Comparative demographics and outcomes of patients by city of admission. (Continuous variables were analyzed using the Mann\u0026ndash;Whitney U test. Categorical variables were compared using the Chi-square test or Fisher\u0026rsquo;s exact test, where applicable.)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"567\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal (N- %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVan (N- %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnkara (N- %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrimary spontaneous pneumothorax\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e174\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026gt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e31.4 (18-75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e29.8( 18-70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e33.0( 19-75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFemale\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eMale\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e33 (18.9)\u003c/p\u003e\n \u003cp\u003e141 (81)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e14 (15.6)\u003c/p\u003e\n \u003cp\u003e76 (84.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e19 (22.6)\u003c/p\u003e\n \u003cp\u003e65 (77.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026gt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCo-morbidity (+)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(-)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e36 (20.7)\u003c/p\u003e\n \u003cp\u003e138 (79.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e7 (7.8)\u003c/p\u003e\n \u003cp\u003e83 (92.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e29 (34.5)\u003c/p\u003e\n \u003cp\u003e55 (65.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking history (+)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;(-)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e104 (59.8)\u003c/p\u003e\n \u003cp\u003e64 (36.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e61 (67.8)\u003c/p\u003e\n \u003cp\u003e29 (32.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e43 (51.2)\u003c/p\u003e\n \u003cp\u003e35 (41.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026gt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVATS\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eThoracotomy\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e171 (98.3)\u003c/p\u003e\n \u003cp\u003e3 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e87 (96.7)\u003c/p\u003e\n \u003cp\u003e3 (3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e84 (100)\u003c/p\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026gt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLength of hospital stay (day)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e6.9 (3-18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e8.23 (3-18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e5.5( 4-12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLength of ICU stay (day)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e0.97 (0-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e0.94 (0-1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.029\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePreoperative Hgb (g/dL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e14.6 (9.6-18.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e15.0 (10.3-18.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e14.3 (9.6-17.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative complication (+)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; (-)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e51 (29.3)\u003c/p\u003e\n \u003cp\u003e123 (70.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e11 (12.2)\u003c/p\u003e\n \u003cp\u003e79 (87.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e40 (47.6)\u003c/p\u003e\n \u003cp\u003e44 (52.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlood type\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e0\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eA\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eB\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eAB\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e174\u003c/p\u003e\n \u003cp\u003e47 (27.0)\u003c/p\u003e\n \u003cp\u003e81 (46.6)\u003c/p\u003e\n \u003cp\u003e32 (18.4)\u003c/p\u003e\n \u003cp\u003e14 (8.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003cp\u003e15 (16.7)\u003c/p\u003e\n \u003cp\u003e49 (54.4)\u003c/p\u003e\n \u003cp\u003e20 (22.2)\u003c/p\u003e\n \u003cp\u003e6 (6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003cp\u003e32 (38.1)\u003c/p\u003e\n \u003cp\u003e32 (38.1)\u003c/p\u003e\n \u003cp\u003e12 (14.3)\u003c/p\u003e\n \u003cp\u003e8 (9.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 208px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRh (+)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eRh (-)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e141 (81.0)\u003c/p\u003e\n \u003cp\u003e33 (19.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e76 (84.4)\u003c/p\u003e\n \u003cp\u003e14 (15.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e65 (77.4)\u003c/p\u003e\n \u003cp\u003e19 (22.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026gt;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eWhen the ABO blood group distribution observed in this study was compared to the national distribution, no significant difference was found using the Chi-square test (\u0026chi;\u0026sup2; = 3.98, p = 0.264). However, when expected frequencies based on large-scale national studies were used (n = 174; A: 73.08, O: 59.16, B: 27.84, AB: 13.92), the Chi-square goodness-of-fit test revealed a statistically significant difference (\u0026chi;\u0026sup2; = 6.21, df = 3, p = 0.045). This suggests that the distribution of blood groups among PSP patients deviates significantly from that of the general population (p \u0026lt; 0.05) (Table 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u0026nbsp;\u003c/strong\u003eObserved and expected frequencies of ABO blood groups were calculated using a national reference distribution, standardized to the study population (n = 174).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlood Type\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eObserved (n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eExpected (Nationwide) (n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e73.08\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e59.16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e27.84\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003eAB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e13.92\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eIn order to balance non-homogeneous groups between the two cities, an IPTW analysis was performed. This evaluation revealed no statistically significant differences in ABO blood group or Rh factor distributions between the two centers (p = 0.999 and p = 0.780, respectively) (Table 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3:\u0026nbsp;\u003c/strong\u003eUsing the Inverse Probability of Treatment Weighting (IPTW) method, balanced means of blood group and Rh positivity rates were compared between the cities of V and A. The analysis revealed no statistically significant differences in either variable between the two groups. Blood type was numerically encoded for analytical purposes.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"444\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 133px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eV (mean)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eA (mean)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value (IPTW)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 133px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlood Type (encoded)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1.509\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1.509\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 133px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRH (positivity rate)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.825\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.813\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTo compare proportions between the national population and the study cohort, a one-sample Z-test was conducted. While the national Rh positivity rate is reported as 84.9%, the rate among PSP patients in our study was found to be 72.7% [9,10]. This difference was statistically significant (Z = -4.80, p \u0026lt; 0.001), supporting the hypothesis that Rh-negative individuals may have a predisposition to pneumothorax. However, this observation does not establish a causal relationship. When a similar Z-test was applied to ABO blood groups, no statistically significant differences were observed between the study population and national data (Table 4).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4:\u0026nbsp;\u003c/strong\u003eA comparison of the sample proportions of each blood group observed in the study with the expected national proportions using the Z-test.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBlood Type\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample Rate\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNationwide rate\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eZ test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e0.466\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e1.204\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e0.270\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e-2.076\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e0.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.814\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 86px;\"\u003e\n \u003cp\u003eAB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 92px;\"\u003e\n \u003cp\u003e0.080\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 109px;\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we aimed to evaluate factors potentially associated with PSP in patients who underwent surgery in two cities with differing atmospheric pressures, and to explore whether ABO blood group and Rh factor show differential distribution patterns within a homogeneous patient population.\u003c/p\u003e \u003cp\u003eThe age difference observed between the two cities was attributed to the earlier onset and wider prevalence of tobacco use in city V (p\u0026thinsp;=\u0026thinsp;0.001) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Comorbid conditions, excluding chronic lung diseases, were more common among patients operated in city A, which may be explained by its status as a university hospital that attracts more complex cases (p\u0026thinsp;=\u0026thinsp;0.001). Consequently, postoperative complications were significantly higher in city A (p\u0026thinsp;=\u0026thinsp;0.001). The significantly longer perioperative hospital stay in city V was attributed to limited surgical table availability in that center (p\u0026thinsp;=\u0026thinsp;0.001). Preoperative Hgb levels were significantly higher in city V, likely due to secondary polycythemia associated with the city\u0026rsquo;s high altitude (p\u0026thinsp;=\u0026thinsp;0.003).\u003c/p\u003e \u003cp\u003eOur study revealed statistically significant differences in both ABO blood group distribution and Rh factor between the study population and the national averages (p\u0026thinsp;=\u0026thinsp;0.008). Among the 174 patients with PSP, 72.7% were Rh-positive, compared to the national prevalence of 84.9%. A one-sample Z-test demonstrated a significantly lower Rh-positivity rate in our PSP cohort (Z = -4.81, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting a possible predisposition to pneumothorax among Rh-negative individuals. Furthermore, the overrepresentation of Rh-negative individuals and blood group A in the PSP population suggests a potential association with PSP rather than a causal relationship. These differences remained statistically significant across multiple analytical methods, including Chi-square and Z-tests, and persisted even after adjustment for potential confounding factors using Inverse IPTW. To reduce the potential heterogeneity between centers, we applied IPTW, balancing confounders such as age, sex, and smoking history. The persistence of disparities in blood group distribution after IPTW suggests that this finding is not merely due to geographic or demographic variability. A national-level goodness-of-fit Chi-square test also revealed a statistically significant difference between observed and expected blood group distributions (χ\u0026sup2; = 6.21, p\u0026thinsp;=\u0026thinsp;0.045), driven primarily by the overrepresentation of blood group A and underrepresentation of blood group O.\u003c/p\u003e \u003cp\u003eThis observation supports the hypothesis that blood group A may be a predisposing factor for PSP. Conversely, blood group O was significantly underrepresented among PSP patients compared to the general population (p\u0026thinsp;=\u0026thinsp;0.03). This finding may indicate that blood group O is less frequently observed among PSP patients, suggesting a possible inverse association. However, the underrepresentation of blood group O does not confirm a direct protective role; rather, it indicates a statistical association. Causal inference would require exploration of the underlying biological mechanisms. Additionally, potential confounders such as age, sex, smoking, and comorbidities may be linked to blood group O. Nonetheless, the robustness of our finding is enhanced by adjustment using IPTW. However, the absence of a healthy control group limits the strength of evidence.\u003c/p\u003e \u003cp\u003eWhen the ABO blood group distribution of PSP patients was compared between the two centers (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), no statistically significant difference was observed (p\u0026thinsp;=\u0026thinsp;0.264). However, when compared with the national blood group distribution, significant deviations were identified among the patient group (p\u0026thinsp;=\u0026thinsp;0.045). This suggests that the observed differences in blood group distribution in our study may be related to the development of PSP rather than geographic variations. In other words, there is no significant difference between the patients from V and A; however, the combined patient population shows a deviation from the healthy national population.\u003c/p\u003e \u003cp\u003eThere is growing interest in the literature regarding the association between blood types and respiratory diseases. Blood group A has been frequently reported in conditions such as pulmonary embolism, COVID-19, and emphysema, whereas blood group O has been associated with a lower risk of deep vein thrombosis and pulmonary embolism [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. However, studies directly evaluating the relationship between blood type and spontaneous pneumothorax remain scarce. From this perspective, our study contributes novel data to the existing literature.\u003c/p\u003e \u003cp\u003ePSP has been suggested to have a genetic component [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], and our study explored its possible correlation with ABO and Rh blood group systems. Similar associations have been established between blood groups and other respiratory conditions such as emphysema, chronic obstructive pulmonary disease (COPD), asthma, and small cell lung cancer [\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In a study by Sahinoglu et al., investigating the relationship between PSP, blood group, and ambient temperature, it was hypothesized that the absence of A and B antigens in blood group O may lead to a different inflammatory response under thermal stress [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this study, the distribution of ABO blood groups and Rh factor among patients diagnosed with PSP was compared with national population data, revealing statistically significant differences. Compared with the general population, PSP patients demonstrated a distinct distribution of ABO blood groups and Rh factor, characterized by a higher prevalence of blood group A, a lower prevalence of blood group O, and reduced Rh positivity.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStudy Limitations\u003c/h2\u003e \u003cp\u003eHowever, this study has certain limitations. Firstly, all participants included had PSP, and thus a direct comparison with a healthy control group was not possible. Nonetheless, since the national blood group distribution was derived from robust population-level data, the comparisons remain valid. Secondly, a larger sample size and future prospective studies are needed to validate and expand upon these findings.\u003c/p\u003e \u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePSP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ePrimary spontaneous pneumothorax\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBody mass index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFLCN\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eFolliculin\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eVATS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eVideo assisted thoracoscopic surgery\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIPTW\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eInverse Probability of Treatment Weighting\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eV\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eVan\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAnkara\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHgb\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHemoglobine\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eICU\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIntensive care unit\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval:\u003c/strong\u003e All procedures involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was approved by the Ethics Committee of Ankara University Faculty of Medicine (approval number: 20055001036-3; registration number: 2025/1036; approval date: 07 January 2026). Due to the retrospective design of the study, the requirement for informed consent was waived by the Ethics Committee. Clinical trial number: not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e All authors provided consent for publication. The consent form was signed by the relevant authors. The patient provided written informed consent for the publication of personal or clinical details, along with any identifying images included in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e The data and materials are available for use by the publisher. The datasets used and/or analyzed in the present study can be obtained from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e The author declares that there are no potential conflicts of interest. This article is protected by copyright. All rights reserved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e The authors declare there is no financial support for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e Concept (SGG,BG,YK,İA,AK,ES,SD), Design (BG,BİES,YK,AK,ES,BMY), Data Collection and/or Processing (SGG,BG,BIES,İA,AK,SD,BMY), Analysis and/or Interpretation (SGG,KS,BİES,YK,İA,ES,SD,BMY)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e We extend our sincere gratitude to all the authors who contributed to this study. We extend our respects to the editorial team and the esteemed referees who evaluated the work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHallifax R. Aetiology of primary spontaneous pneumothorax. J Clin Med. 2022;11:490. doi:10.3390/jcm11030490\u003c/li\u003e\n\u003cli\u003eCanavar A, Erk M, Seyrek Y, et al. Do atmospheric pressure and air pollution affect the incidence of primary spontaneous pneumothorax? Curr Thorac Surg. 2024;9. doi:10.26663/cts.2024.015\u003c/li\u003e\n\u003cli\u003eHaberal MA, Akar E, Şeng\u0026ouml;ren Dikiş \u0026Ouml;, \u0026Ouml;zkaya M, Ay MO, Kaya H, Y\u0026uuml;ksel M. Effects of atmospheric changes on spontaneous pneumothorax. Eurasian J Emerg Med. 2022;21(3).\u003c/li\u003e\n\u003cli\u003eHuan NC, Sidhu C, Thomas R. Pneumothorax: classification and etiology. Clin Chest Med. 2021;42:711\u0026ndash;727. doi:10.1016/j.ccm.2021.08.007\u003c/li\u003e\n\u003cli\u003eWong A, Galiabovitch E, Bhagwat K. Management of primary spontaneous pneumothorax: a review. ANZ J Surg. 2019;89:303\u0026ndash;308. doi:10.1111/ans.14713\u003c/li\u003e\n\u003cli\u003eWilson PM, Rymeski B, Xu X, Hardie W. An evidence-based review of primary spontaneous pneumothorax in the adolescent population. J Am Coll Emerg Physicians Open. 2021;2:e12449. doi:10.1002/emp2.12449\u003c/li\u003e\n\u003cli\u003eBoone PM, Scott RM, Marciniak SJ, Henske EP, Raby BA. The genetics of pneumothorax. Am J Respir Crit Care Med. 2019;199:1344\u0026ndash;1357. doi:10.1164/rccm.201807-1212CI\u003c/li\u003e\n\u003cli\u003eLouw EH, Shaw JA, Koegelenberg CFN. New insights into spontaneous pneumothorax: a review. Afr J Thorac Crit Care Med. 2023;29(4):143\u0026ndash;148.\u003c/li\u003e\n\u003cli\u003eTorun YA, Kaynar LG, Karakukcu C, et al. ABO and Rh blood group distribution in Kayseri Province, Turkey. Turk J Haematol. 2012;29:97\u0026ndash;98. doi:10.5505/tjh.2012.26918\u003c/li\u003e\n\u003cli\u003eYuksel Salduz ZI, Cetin G, Karatoprak C, et al. ABO and Rh blood group distribution in Istanbul Province (Turkey). Istanbul Med J. 2015;16:98\u0026ndash;100. doi:10.5152/imj.2015.14890\u003c/li\u003e\n\u003cli\u003eOguz S, Camci G, Kazan M. The prevalence of cigarette smoking and knowledge status for diseases caused by smoking among university students. Van Med J. 2018;25:332\u0026ndash;337. doi:10.5505/vtd.2018.02411\u003c/li\u003e\n\u003cli\u003eSun X, Feng J, Wu W, Peng M, Shi J. ABO blood types associated with the risk of venous thromboembolism in Han Chinese people: a hospital-based study of 200,000 patients. Sci Rep. 2017;7:42925. doi:10.1038/srep42925\u003c/li\u003e\n\u003cli\u003eWolpin BM, Kabrhel C, Varraso R, et al. Prospective study of ABO blood type and the risk of pulmonary embolism in two large cohort studies. Thromb Haemost. 2010;104:962\u0026ndash;971. doi:10.1160/TH10-05-0312\u003c/li\u003e\n\u003cli\u003eAsiwe JN, Umoren EB, Kolawole TA, et al. Does ABO blood type implicate susceptibility to respiratory abnormalities? A controlled cross-sectional study among indigenous university students in Rivers State, Nigeria. J Complement Altern Med Res. 2023;23:35\u0026ndash;45. doi:10.9734/jocamr/2023/v23i1470\u003c/li\u003e\n\u003cli\u003eSun W, Kechris K, Jacobson S, et al. Common genetic polymorphisms influence blood biomarker measurements in COPD. PLoS Genet. 2016;12:e1006011. doi:10.1371/journal.pgen.1006011\u003c/li\u003e\n\u003cli\u003eSu S, Guo L, Ma T, et al. Association of ABO blood group with respiratory disease hospitalization and severe outcomes: a retrospective cohort study in blood donors. Int J Infect Dis. 2022;122:21\u0026ndash;29. doi:10.1016/j.ijid.2022.05.019\u003c/li\u003e\n\u003cli\u003eMroczek B, Sitko Z, Sujewicz A, Wolinska W, Karpeta-Pawlak I, Kurpas D. Blood group and incidence of asthma and chronic obstructive pulmonary disease. Adv Exp Med Biol. 2018;1114:31\u0026ndash;39. doi:10.1007/5584_2018_203\u003c/li\u003e\n\u003cli\u003eSingh S, Yadav AS. Distribution of ABO and Rh (D) allele frequency among COPD patients. Int J Health Sci Res. 2015;5(1):244\u0026ndash;249.\u003c/li\u003e\n\u003cli\u003eEren C, Guner Akbiyik A, Okten IN. Analysis of the relationship between blood groups and lung cancer risk depending on histology. J DU Health Sci Inst. 2021;11(3):386\u0026ndash;390. doi:10.33631/duzcesbed.867713\u003c/li\u003e\n\u003cli\u003eBruun-Rasmussen P, Dziegiel MH, Banasik K, Johansson PI, Brunak S. Associations of ABO and Rhesus D blood groups with phenome-wide disease incidence: a 41-year retrospective cohort study of 482,914 patients. eLife. 2023;12:e83116. doi:10.7554/eLife.83116\u003c/li\u003e\n\u003cli\u003eSahinoglu T, Katrancioglu O. Impact of weather conditions and blood groups on primary spontaneous pneumothorax. Curr Thorac Surg. 2020;5. doi:10.26663/cts.2020.00013\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Primary spontaneous pneumothorax, Blood type, ABO, Rh ","lastPublishedDoi":"10.21203/rs.3.rs-8569383/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8569383/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eBackground\u003c/b\u003e \u003c/p\u003e \u003cp\u003eFirst described in the early 19th century as \u0026ldquo;simple pneumothorax,\u0026rdquo; primary spontaneous pneumothorax (PSP) refers to the presence of air within the pleural cavity without an identifiable secondary cause. PSP predominantly affects males, smokers, tall individuals, and those with a low body mass index. However, the occurrence of PSP in individuals without these classical risk factors, as well as variability among patients with similar phenotypes, suggests that additional pathophysiological mechanisms may contribute to disease susceptibility. Although ABO and Rh blood group variations have been associated with several pulmonary and systemic diseases, data regarding their relationship with PSP remain limited.\u003c/p\u003e \u003cp\u003e \u003cb\u003eObjective\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThis study aimed to evaluate whether ABO and Rh blood group subtypes are associated with PSP by analyzing a homogeneous surgical patient cohort from two cities with distinct altitudes and comparing the findings with national blood group distribution.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMethods\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA total of 174 patients who underwent surgery for PSP between 2021 and 2024 were retrospectively reviewed from two centers located in geographically distinct altitude regions. ABO and Rh distributions were analyzed using Pearson\u0026rsquo;s chi-square test, inverse probability of treatment weighting (IPTW), and one-sample Z testing.\u003c/p\u003e \u003cp\u003e \u003cb\u003eResults\u003c/b\u003e \u003c/p\u003e \u003cp\u003eCompared with national data, PSP patients showed an overrepresentation of blood group A, an underrepresentation of blood group O, and a lower prevalence of Rh positivity.\u003c/p\u003e","manuscriptTitle":"ABO and Rh Blood Group Distributions in Patients With Primary Spontaneous Pneumothorax: A Comparative Population-Based Study Across Two Altitudes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-10 11:38:57","doi":"10.21203/rs.3.rs-8569383/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-02T13:11:01+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-28T14:30:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"332160981452227269721744445896037522","date":"2026-02-19T11:41:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-13T17:15:11+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-09T06:34:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"328091424284819293405039101815610677038","date":"2026-02-03T11:51:57+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-30T11:39:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"221443576304389794573914269875284906689","date":"2026-01-30T04:59:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"165543498281502178176613821086509479958","date":"2026-01-29T17:18:53+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-29T06:17:41+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-16T11:48:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-14T02:32:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-14T02:31:19+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pulmonary Medicine","date":"2026-01-10T15:38:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"04314ab7-d14e-4ae6-ab02-4adac7097ba7","owner":[],"postedDate":"February 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T16:08:26+00:00","versionOfRecord":{"articleIdentity":"rs-8569383","link":"https://doi.org/10.1186/s12890-026-04303-1","journal":{"identity":"bmc-pulmonary-medicine","isVorOnly":false,"title":"BMC Pulmonary Medicine"},"publishedOn":"2026-04-25 15:59:50","publishedOnDateReadable":"April 25th, 2026"},"versionCreatedAt":"2026-02-10 11:38:57","video":"","vorDoi":"10.1186/s12890-026-04303-1","vorDoiUrl":"https://doi.org/10.1186/s12890-026-04303-1","workflowStages":[]},"version":"v1","identity":"rs-8569383","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8569383","identity":"rs-8569383","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}