Periodontal Disease and Healthcare Expenditures: A 7-Year Cohort Study of Employees in Japan

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Although international studies have demonstrated that periodontal treatment can mitigate medical costs, comprehensive research examining the relationship among oral health, healthcare expenditures, and systemic disease inset is still scarce, particularly in Japan. Therefore, this study examined the associations among oral health, medical and dental expenditures, and the incidence of lifestyle-related diseases, using annual health checkup data. Methods: This long-term cohort study analyzed data from 467 male employees who participated in annual health and dental check-ups from 2009-2014. Participants were categorized into periodontitis and non-periodontitis groups based on the community periodontal index. We compared baseline characteristics and healthcare expenditures (medical, dental, pharmaceutical and total healthcare) between two groups. Longitudinal changes in glycated hemoglobin (HbA1c) levels were evaluated using a mixed model for repeated measures. Results: Participants in the periodontitis group (n=87) was significantly older than the non-periodontitis group (n=380). Median annual medical expenditure (¥41,160 vs ¥21,770; p=0.03), dental expenditure (¥12,760 vs ¥7,030; p=0.01), and total healthcare expenditure (¥97,030 vs ¥51,415; p=0.002) were significantly higher in the periodontitis group. No significant difference in HbA1c trajectories or the risk of exceeding an HbA1c threshold of 5.6% or 6.5% was observed between the two groups. Conclusion: Poor periodontal health is associated with increased medical and dental expenditures. Promoting oral health in the workplace may be a cost-effective strategy for reducing the overall healthcare burden. periodontitis community periodontitis index healthcare expenditure annual health check-up Figures Figure 1 Introduction The prevalence of dental diseases is remarkably high worldwide. In 2010, the global cost of dental treatments reached 298 billion USD, accounting for 4.6% of total healthcare expenditures [ 1 ]. Furthermore, productivity loss attribute to dental diseases, such as dental caries, periodontitis, and tooth loss, is comparable to that caused by lower respiratory infections, one of the top ten causes of death in the world. Periodontitis is a biofilm-mediated, non-communicable, chronic inflammatory disease that gradually deteriorates the tooth-supporting structures [ 2 ]. Several studies have reported the association of between periodontitis and systemic diseases such as diabetes and cardiovascular diseases [3­7]. Managing dental diseases could potentially reduce not only dental costs but also overall medical expenditures. Oral diseases, particularly periodontitis, are among the most prevalent health conditions globally, and are associated with systemic diseases such as diabetes, cardiovascular diseases, and chronic kidney disease. In Japan, initiatives such as incorporating oral health items into the Specific Health Checkups and Specific Health Guidance and the revision of the Total Health Promotion Plan guidelines underscore the importance of oral health in workplace health promotion. Recent evidence has highlighted the bidirectional relationship between oral infections and systemic diseases. Improved oral hygiene has been shown to attenuate cardiovascular diseases risks, potentially by reducing systemic inflammation [ 8 ]. Moreover, the concept of an "oral-systemic axis" has gained attention, suggesting that periodontal disease may act as a chronic contributor to metabolic and vascular disorders [ 9 ]. These findings indicate that maintaining good oral health could help prevent dental complications and reduce broader health risks and associated costs. Internationally, several studies have investigated the relationship between periodontal treatment and medical costs. Albert et al. demonstrated that periodontal treatment could help reduce medical costs in patients with systemic diseases [ 10 ]. Similarly, used insurance data to examine the effects of periodontal treatment on five systemic conditions, including diabetes and coronary artery disease, and reported reductions in medical costs and hospitalization rates among treated patients [ 11 ]. In Japan, studies have focused on specific populations. For example, Sato et al. investigated medical expenditures in elderly populations [ 12 ], whereas Ichihashi et al. examined both medical and dental expenditures among young and middle-aged workers [ 13 ]. Additionally, a recent report from health care claims from municipalities indicated that individuals with co-occurring periodontitis and diabetes incurred significantly higher annual medical expenses than those without either condition, emphasizing the importance of collaboration between medical and dental care [ 14 ]. Their findings suggested that regular and semi-regular workplace dental examinations are associated with reductions in cumulative dental expenditures. However, few comprehensive studies have explored the relationship among oral health, dental expenditures, total medical costs, and systemic diseases onset. The Sunstar Group has implemented a healthcare retreat program since 1985, targeting employees with obesity and cardiovascular risk factors. Previous studies have demonstrated the effectiveness of this program in improving anthropometric and metabolic indicators [ 15 ]. In this framework, the present study aims to investigate whether oral health status, as evaluated during routine dental examinations, is associated with medical expenditures and metabolic markers. Methods Study design and participants This study was conducted among approximately 1500 employees of the Sunstar Group located in Japan. Participants employed by the Sunstar Group from 2007 to 2014 and underwent health check-ups in all years during this period. Individuals who left the company group in the subsequent three years were excluded from the study. Data Collection and Measurements Health check-up data were systematically collected from annual check-ups conducted by the Sunstar Group in February and March every year, as mandated by the Industrial Safety and Health Act of Japan for employees living in Japan. The health check-up consisted of anthropometry, laboratory tests including urine and blood tests, and a self-administrated questionnaire about disease history, family history, and lifestyle (Supplement table). Height and weight were simultaneously measured with a scale (Ueda Avance, Osaka, Japan). Body mass index (BMI) was calculated as body weight (kg) divided by height squared (m 2 ). Waist circumference was measured at the level of the umbilicus in one's standing position using a tape measure. Systolic and diastolic blood pressure (SBP and DBP, respectively) was measured by an automatic sphygmomanometer (Elk Corporation, Osaka, Japan). Blood tests were performed to analyze the concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride (TG), fasting plasma glucose (FPG), and glycated hemoglobin (HbA1c). HbA1c was partially measured using the Japan Diabetes Society (JDS) method, which yields values approximately 0.4% lower than those obtained by the National Glyco-hemoglobin Standardization Program (NGSP). To ensure international comparability, all HbA1c values were converted to NGSP equivalents using the following formula: NGSP (%) = 1.02*JDS (%) + 0.25%. Additionally, oral health conditions were examined in the annual dental check-ups conducted in the workplace by trained dentists. Periodontitis group defined as having at least one tooth with community periodontal index (CPI) code ≥ 3, and non-periodontitis group defined as having all teeth with CPI < 3. Furthermore, health insurance claims data were used to calculate average annual expenditures per participant for the following categories: medical care costs, dental care costs, pharmaceutical costs, total healthcare costs. Statistical analysis Normally distributed continuous variables were expressed as the mean and standard deviations and compared using Welch’s t-test, which does not assume equal variances between groups. Non-normally distributed continuous variables were expressed as medians and interquartile ranges and compared using the Mann–Whitney U test. Categorical variables were expressed as a numbers and proportions and analyzed using the chi-squared test or Fisher’s exact test. Study participants were divided into two groups according to baseline periodontal status: participants group (CPI ≥ 3) and non periodontitis group (CPI < 3). Annual expenditures and hyperglycemia (HbA1c ≥ 5.6 and ≥ 6.5) during the follow-up period were compared between two groups. Longitudinal changes in HbA1c levels between the two groups were evaluated using a mixed-effects model for repeated measures (MMRM). HbA1c levels at each time point during the 7-year follow-up were treated as the dependent variable. Fixed effects included periodontal status group (periodontitis vs. non-periodontitis), time, and the group-by-time interaction. Baseline HbA1c, age, smoking status, exercise habits, and dietary regularity were included as covariate. To evaluate the long-term association between baseline periodontal status and the risk of elevated HbA1c levels, we used Cox proportional hazards models. Two outcomes (HbA1c ≥ 5.6 and ≥ 6.5) were adopted. For each outcome, the adjusted hazard ratio (HR) and its 95% confidence interval (CI) were calculated. The models were adjusted for baseline covariates, including age, smoking status, exercise habits, and dietary regularity. All probability values were two-tailed, and the p-value of < 0.05 was considered statistically significant. All analyses were conducted using Stata Version 17 (StataCorp, College Station, TX, USA). Ethical considerations Individual informed consent was waived for the use of de-identified clinical data according to the national ethical guidelines of Japan. Instead, an opt-out approach was applied for this study. All personal identifiers were removed before the researchers obtained the dataset from the Sunstar Group. The study protocol was approved by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241) and was conducted in accordance with the principles of the Declaration of Helsinki [ 16 ]. Results Baseline Physical, Oral, and Laboratory Findings A total of 467 male participants were included in the analysis, consisting of 87 individuals in the periodontitis group and 380 individuals in the non-periodontitis group. As shown in Table 1, participants in the periodontitis group were significantly older than those in the non-periodontitis group (48.4 ± 8.1 years vs 43.6 ± 8.8 years, p < 0.001). The periodontitis group showed a slightly lower mean height (170.6 ± 5.9 cm vs. 172.0 ± 5.8 cm, p = 0.45), while body weight (BW), waist circumference and body mass index (BMI) were comparable between both groups (BW: 75.4 ± 10.8 kg vs. 76.4 ± 10.2 kg, p = 0.44; waist circumference: 91.1 ± 7.7 cm vs. 90.6 ± 7.2 cm, p = 0.59; BMI: 25.9 ± 3.4 vs. 25.8 ± 3.1, p = 0.79). For glycemic parameters, the periodontitis group tended to have slightly higher HbA1c (5.6% ± 0.9% vs 5.5% ± 0.7%) and fasting plasma glucose levels (105.5 ± 22.6 mg/dL vs 101.7 ± 16.8 mg/dL) compared to the non-periodontitis group, though these differences were not statistically significant (p = 0.15 and p = 0.14, respectively). The proportion of smokers was slightly higher in the periodontitis group (47 [54.0%] vs. 185 [48.7%], p = 0.43). Furthermore, there was no significant difference in the number of untreated teeth between the periodontitis group and the non-periodontitis group (39 [44.8%] vs 142 [37.4%], p = 0.24). Healthcare Expenditures As presented in Table 2, participants with periodontitis group incurred significantly higher median annual medical expenditure (¥41,160 vs ¥21,770, p = 0.03), dental expenditure (¥12,760 vs ¥7,030, p = 0.01), and total healthcare expenditure (¥97,030 vs ¥51,415; p = 0.002). Although the median pharmaceutical expenditure was higher in the participants with periodontitis group, but the difference did not reach statistically significance (¥14,000 vs ¥9,335, p = 0.23) Impact of Baseline Periodontal Status on Long-Term Glycemic Trajectories The trajectories of the adjusted mean HbA1c levels at baseline and during the 7-year follow-up period were illustrated in Figure. The MMRM analysis showed that, seven years later, these values were 5.69% (95% CI 5.62–5.76) and 5.69% (95% CI 5.54–5.84), respectively, with no statistically significant difference between the groups (difference of 0.07%, P = 0.94). The association between baseline periodontitis status and subsequent increases in HbA1c using Cox proportional hazards models. For Outcome 1 (HbA1c ≥ 5.6%), 124 events occurred among 467 participants. The adjusted hazard ratio (HR) for participants with periodontitis compared with those without was 0.90 (95% CI: 0.62–1.31, p = 0.59). For Outcome 2 (HbA1c ≥ 6.5%), 27 events were observed, with an adjusted HR of 1.41 (95% CI: 0.65–3.03, p = 0.38) for participants with periodontitis. No statistically significant associations were observed between periodontitis status and increases in HbA1c in either outcome. Discussion This study investigated the relationship between periodontal disease and healthcare expenditures in a male working-age population in Japan. Our findings demonstrated that individuals with signs of periodontitis, defined by a community periodontal index (CPI) score of 3 or higher, incurred significantly higher annual medical expenditure, dental expenditure, and total healthcare expenditure compared to those without periodontitis. Although no statistically significant differences were observed in pharmaceutical expenditures, a consistent trend of elevated costs was evident in the periodontitis group, underscoring the potential economic burden associated with periodontal disease in this population. The link between periodontal health and systemic disease has been increasingly supported by a growing body of literature. For example, a large cohort study in Europe reported that improvements in oral hygiene care were associated with a reduction in cardiovascular disease risk, thereby suggesting that periodontal inflammation may contribute to systemic vascular dysfunction [ 8 ]. Furthermore, a recent editorial discussed the concept of “oral-systemic axis,”, emphasizing that periodontal disease may exacerbate metabolic and cardiovascular conditions through chronic low-grade inflammation [ 9 ]. Our findings reinforce these reports by demonstrating that employees with poorer periodontal status (CPI ≥ 3) incurred significantly higher medical expenditures, taken together, these data suggest that oral health not only influences systemic physiological parameters but also serves as an important causal factor for healthcare cost in working populations. Therapeutic cost is another important outcome. Internationally, several studies have reported associations between poor oral health and increased healthcare costs. However, research specifically investigating this link within the Japanese context has been limited. Notably, Sato et al. reported that severe periodontitis was associated with increased inpatient and total medical expenditures among elderly adults aged 80 years, using periodontal inflamed surface area (PISA) as an indicator [ 12 ]. More recently, Ichihashi et al. demonstrated that regular dental check-ups were associated with reduced cumulative medical and dental expenditures over a 12-year follow-up among employed adults, suggesting a preventive benefit of sustained oral care [ 13 ]. Furthermore, Kinugawa et al specifically reported that the co-existence of periodontitis and diabetes led to a significant increase in healthcare expenditures [ 14 ], indicating a profound economic impact of this "oral-systemic axis." Our study expands the literature by focusing on a middle-aged workforce and demonstrating that not only dental expenditure but also medical expenditure and total healthcare expenditure were higher among individuals with clinical evidence of periodontitis. A significant finding of our study is the reporting of total healthcare expenditures, which underscores the broader economic implications of oral health status in working populations. A related study by Masuko et al. demonstrated that the location of dental check-ups either conducted at the workplace or in external clinics, were significantly associated with absenteeism among Japanese workers [ 17 ]. Their findings underscore the relevance of access to preventive dental care in occupational settings. Our study complements this perspective by showing that both the accessibility of dental care and the actual periodontal health status, as reflected by CPI codes, may influence long-term healthcare expenditures. Together, these results suggested that promoting oral health within corporate health systems through both regular access and effective periodontal disease management could yield measurable benefits in terms of worker productivity and medical cost containment. As previously mentioned, the “oral-systemic axis” suggests that periodontal disease may exacerbate metabolic and cardiovascular conditions through chronic low-grade inflammation. Meta-analyses has substantiated a positive bidirectional association between periodontitis and diabetes mellitus [ 18 ]. Furthermore, recent research has demonstrated that infection with periodontal pathogens adversely affects gut microbiota health, condition leading to systemic insulin resistance and skeletal muscle metabolic dysfunction [ 19 ]. While our analysis revealed a significant association between the presence of periodontal disease and higher medical, dental, and total healthcare expenditures, no statistically significant association was observed between baseline periodontal status and changes in glycemic parameters over the 7-year follow-up period. These findings suggested that in contrast to directly causing a clear deterioration in glycemic levels, periodontal disease may contribute to broader health issues and the associated increase in medical expenditures through undetected, chronic inflammation. This study has several limitations. First, as a retrospective cohort study, it could not establish a definitive causal relationship between periodontal disease and healthcare expenditures. A kind of personality such as laziness might be a cause of both dental and medical conditions. Second, the study was limited to health check-up and medical expenditure data. Consequently, detailed participant lifestyle factors (e.g., dietary habits, stress), genetic factors, or specific periodontal treatment details, which could act as confounding variables, may not have been fully captured, potentially influencing our results. Third, this study was conducted among employees of a single company group, limiting the generalizability of the findings. Fourth, the 7-year observation period might be relatively short, potentially insufficient for evaluating long-term effects. Finally, the lack of detailed oral health data (e.g., probing depth, attachment loss, or more specific periodontal tissue conditions) and data on specific oral hygiene behaviors also constrains the interpretation of our findings. Future studies using a prospective design with more comprehensive data on lifestyle factors and detailed oral health assessments is warranted. Conclusion In conclusion, our findings demonstrated that periodontal disease is associated with a significant elevated in medical, dental, and total healthcare expenditures. These results highlight the importance of integrating oral health into corporate wellness programs as a cost-effective strategy to mitigate the overall healthcare burden. Abbreviations The list of abbreviations is not provided, as all abbreviations used in this manuscript are defined upon first appearance. Declarations Ethics approval and consent to participate The need for written informed consent was waived by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241). Ethics Committee due to the retrospective nature of the study, which used anonymized data. All personal identifiers were removed before the researchers obtained the dataset from the Sunstar Group. The study protocol was approved by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241) and was conducted in accordance with the principles of the Declaration of Helsinki. Consent to publication All authors approved the final manuscript for publication. Funding This research did receive funding. Keiichi Matsuzaki received funding from Sunstar Foundation. The funding source did not influence the conduct of this work. Author Contribution K.M: Conceptualisation, Acquisition of data, Analysis and interpretation of data, Drafting of the manuscript, Critical revision of the paper for important intellectual content,Statistical analysis, Provision of study materials, Obtaining fundingT.S: Analysis and interpretation of data, Critical revision of the paper for important intellectual content, Statistical analysisT.K: Critical revision of the paper for important intellectual content, Provision of study materials, Obtaining funding, Supervision Acknowledgement Our sincere appreciation is extended to the participants for their invaluable contributions to the study.We are especially grateful to Mr. Shunya Kobayashi for his valuable support in data preparation and statistical analysis.We also thank Mr. Sato, Mr. Tanimizu, Ms. Takaine and our colleagues. Data Availability The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. 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Prev Med Rep. 2018;13:170–4. World Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013;310(20):2191–4. Masuko S, Zaitsu T, Oshiro A, Ishimaru M, Aida J. Association between place of dental check-ups and work absenteeism among Japanese workers. J Occup Health. 2023 Jan-Dec;65(1):e12415. Stöhr J, Barbaresko J, Neuenschwander M, Schlesinger S. Bidirectional association between periodontal disease and diabetes mellitus: a systematic review and meta-analysis of cohort studies. Sci Rep. 2021;11(1):13686. Yamazaki K. Oral-gut axis as a novel biological mechanism linking periodontal disease and systemic diseases: A review. Jpn Dent Sci Rev. 2023;59:273–80. Tables Tables are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files sunstardtable251009.xlsx sunstardsuppleq251104.xlsx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 03 Dec, 2025 Reviews received at journal 30 Nov, 2025 Reviews received at journal 23 Nov, 2025 Reviewers agreed at journal 08 Nov, 2025 Reviewers agreed at journal 07 Nov, 2025 Reviewers invited by journal 06 Nov, 2025 Editor assigned by journal 05 Nov, 2025 Submission checks completed at journal 04 Nov, 2025 First submitted to journal 04 Nov, 2025 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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1","display":"","copyAsset":false,"role":"figure","size":63509,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Slide1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7813290/v1/e06482b3ff7fdfeda732b2ba.jpg"},{"id":96369216,"identity":"6346dd4e-541d-40b5-85a6-1ed46d621c8e","added_by":"auto","created_at":"2025-11-20 10:20:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":566496,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7813290/v1/d412146c-b8d9-4955-995e-0844508b62db.pdf"},{"id":96270191,"identity":"53f5dc5d-4ef0-43b8-9cf7-95389c700ce4","added_by":"auto","created_at":"2025-11-19 09:15:26","extension":"xlsx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":19069,"visible":true,"origin":"","legend":"","description":"","filename":"sunstardtable251009.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7813290/v1/4890b1626f01033329fa7696.xlsx"},{"id":96364904,"identity":"2a5375d4-b327-4712-bb6c-4a31ea616d33","added_by":"auto","created_at":"2025-11-20 10:09:47","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":11104,"visible":true,"origin":"","legend":"","description":"","filename":"sunstardsuppleq251104.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7813290/v1/0765124712b7b63b4af1153b.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Periodontal Disease and Healthcare Expenditures: A 7-Year Cohort Study of Employees in Japan","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe prevalence of dental diseases is remarkably high worldwide. In 2010, the global cost of dental treatments reached 298\u0026nbsp;billion USD, accounting for 4.6% of total healthcare expenditures [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Furthermore, productivity loss attribute to dental diseases, such as dental caries, periodontitis, and tooth loss, is comparable to that caused by lower respiratory infections, one of the top ten causes of death in the world.\u003c/p\u003e\u003cp\u003ePeriodontitis is a biofilm-mediated, non-communicable, chronic inflammatory disease that gradually deteriorates the tooth-supporting structures [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Several studies have reported the association of between periodontitis and systemic diseases such as diabetes and cardiovascular diseases [3\u0026shy;7]. Managing dental diseases could potentially reduce not only dental costs but also overall medical expenditures. Oral diseases, particularly periodontitis, are among the most prevalent health conditions globally, and are associated with systemic diseases such as diabetes, cardiovascular diseases, and chronic kidney disease. In Japan, initiatives such as incorporating oral health items into the Specific Health Checkups and Specific Health Guidance and the revision of the Total Health Promotion Plan guidelines underscore the importance of oral health in workplace health promotion. Recent evidence has highlighted the bidirectional relationship between oral infections and systemic diseases. Improved oral hygiene has been shown to attenuate cardiovascular diseases risks, potentially by reducing systemic inflammation [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Moreover, the concept of an \"oral-systemic axis\" has gained attention, suggesting that periodontal disease may act as a chronic contributor to metabolic and vascular disorders [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. These findings indicate that maintaining good oral health could help prevent dental complications and reduce broader health risks and associated costs.\u003c/p\u003e\u003cp\u003eInternationally, several studies have investigated the relationship between periodontal treatment and medical costs. Albert et al. demonstrated that periodontal treatment could help reduce medical costs in patients with systemic diseases [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Similarly, used insurance data to examine the effects of periodontal treatment on five systemic conditions, including diabetes and coronary artery disease, and reported reductions in medical costs and hospitalization rates among treated patients [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In Japan, studies have focused on specific populations. For example, Sato et al. investigated medical expenditures in elderly populations [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], whereas Ichihashi et al. examined both medical and dental expenditures among young and middle-aged workers [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAdditionally, a recent report from health care claims from municipalities indicated that individuals with co-occurring periodontitis and diabetes incurred significantly higher annual medical expenses than those without either condition, emphasizing the importance of collaboration between medical and dental care [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Their findings suggested that regular and semi-regular workplace dental examinations are associated with reductions in cumulative dental expenditures. However, few comprehensive studies have explored the relationship among oral health, dental expenditures, total medical costs, and systemic diseases onset.\u003c/p\u003e\u003cp\u003eThe Sunstar Group has implemented a healthcare retreat program since 1985, targeting employees with obesity and cardiovascular risk factors. Previous studies have demonstrated the effectiveness of this program in improving anthropometric and metabolic indicators [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In this framework, the present study aims to investigate whether oral health status, as evaluated during routine dental examinations, is associated with medical expenditures and metabolic markers.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy design and participants\u003c/h2\u003e\u003cp\u003eThis study was conducted among approximately 1500 employees of the Sunstar Group located in Japan. Participants employed by the Sunstar Group from 2007 to 2014 and underwent health check-ups in all years during this period. Individuals who left the company group in the subsequent three years were excluded from the study.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eData Collection and Measurements\u003c/h3\u003e\n\u003cp\u003eHealth check-up data were systematically collected from annual check-ups conducted by the Sunstar Group in February and March every year, as mandated by the Industrial Safety and Health Act of Japan for employees living in Japan. The health check-up consisted of anthropometry, laboratory tests including urine and blood tests, and a self-administrated questionnaire about disease history, family history, and lifestyle (Supplement table).\u003c/p\u003e\u003cp\u003eHeight and weight were simultaneously measured with a scale (Ueda Avance, Osaka, Japan). Body mass index (BMI) was calculated as body weight (kg) divided by height squared (m\u003csup\u003e2\u003c/sup\u003e). Waist circumference was measured at the level of the umbilicus in one's standing position using a tape measure. Systolic and diastolic blood pressure (SBP and DBP, respectively) was measured by an automatic sphygmomanometer (Elk Corporation, Osaka, Japan). Blood tests were performed to analyze the concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride (TG), fasting plasma glucose (FPG), and glycated hemoglobin (HbA1c). HbA1c was partially measured using the Japan Diabetes Society (JDS) method, which yields values approximately 0.4% lower than those obtained by the National Glyco-hemoglobin Standardization Program (NGSP). To ensure international comparability, all HbA1c values were converted to NGSP equivalents using the following formula: NGSP (%)\u0026thinsp;=\u0026thinsp;1.02*JDS (%)\u0026thinsp;+\u0026thinsp;0.25%.\u003c/p\u003e\u003cp\u003eAdditionally, oral health conditions were examined in the annual dental check-ups conducted in the workplace by trained dentists. Periodontitis group defined as having at least one tooth with community periodontal index (CPI) code\u0026thinsp;\u0026ge;\u0026thinsp;3, and non-periodontitis group defined as having all teeth with CPI\u0026thinsp;\u0026lt;\u0026thinsp;3. Furthermore, health insurance claims data were used to calculate average annual expenditures per participant for the following categories: medical care costs, dental care costs, pharmaceutical costs, total healthcare costs.\u003c/p\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eNormally distributed continuous variables were expressed as the mean and standard deviations and compared using Welch\u0026rsquo;s t-test, which does not assume equal variances between groups. Non-normally distributed continuous variables were expressed as medians and interquartile ranges and compared using the Mann\u0026ndash;Whitney U test. Categorical variables were expressed as a numbers and proportions and analyzed using the chi-squared test or Fisher\u0026rsquo;s exact test. Study participants were divided into two groups according to baseline periodontal status: participants group (CPI\u0026thinsp;\u0026ge;\u0026thinsp;3) and non periodontitis group (CPI\u0026thinsp;\u0026lt;\u0026thinsp;3). Annual expenditures and hyperglycemia (HbA1c\u0026thinsp;\u0026ge;\u0026thinsp;5.6 and \u0026ge;\u0026thinsp;6.5) during the follow-up period were compared between two groups. Longitudinal changes in HbA1c levels between the two groups were evaluated using a mixed-effects model for repeated measures (MMRM). HbA1c levels at each time point during the 7-year follow-up were treated as the dependent variable. Fixed effects included periodontal status group (periodontitis vs. non-periodontitis), time, and the group-by-time interaction. Baseline HbA1c, age, smoking status, exercise habits, and dietary regularity were included as covariate. To evaluate the long-term association between baseline periodontal status and the risk of elevated HbA1c levels, we used Cox proportional hazards models. Two outcomes (HbA1c\u0026thinsp;\u0026ge;\u0026thinsp;5.6 and \u0026ge;\u0026thinsp;6.5) were adopted. For each outcome, the adjusted hazard ratio (HR) and its 95% confidence interval (CI) were calculated. The models were adjusted for baseline covariates, including age, smoking status, exercise habits, and dietary regularity.\u003c/p\u003e\u003cp\u003eAll probability values were two-tailed, and the p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant. All analyses were conducted using Stata Version 17 (StataCorp, College Station, TX, USA).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eEthical considerations\u003c/h3\u003e\n\u003cp\u003e Individual informed consent was waived for the use of de-identified clinical data according to the national ethical guidelines of Japan. Instead, an opt-out approach was applied for this study. All\u003c/p\u003e\u003cp\u003epersonal identifiers were removed before the researchers obtained the dataset from the Sunstar\u003c/p\u003e\u003cp\u003eGroup. The study protocol was approved by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241) and was conducted in accordance with the principles of the Declaration of Helsinki [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eBaseline Physical, Oral, and Laboratory Findings\u003c/h2\u003e\u003cp\u003eA total of 467 male participants were included in the analysis, consisting of 87 individuals in the periodontitis group and 380 individuals in the non-periodontitis group. As shown in Table\u0026nbsp;1, participants in the periodontitis group were significantly older than those in the non-periodontitis group (48.4\u0026thinsp;\u0026plusmn;\u0026thinsp;8.1 years vs 43.6\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8 years, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The periodontitis group showed a slightly lower mean height (170.6\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9 cm vs. 172.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.8 cm, p\u0026thinsp;=\u0026thinsp;0.45), while body weight (BW), waist circumference and body mass index (BMI) were comparable between both groups (BW: 75.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.8 kg vs. 76.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.2 kg, p\u0026thinsp;=\u0026thinsp;0.44; waist circumference: 91.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.7 cm vs. 90.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2 cm, p\u0026thinsp;=\u0026thinsp;0.59; BMI: 25.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4 vs. 25.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1, p\u0026thinsp;=\u0026thinsp;0.79). For glycemic parameters, the periodontitis group tended to have slightly higher HbA1c (5.6% \u0026plusmn; 0.9% vs 5.5% \u0026plusmn; 0.7%) and fasting plasma glucose levels (105.5\u0026thinsp;\u0026plusmn;\u0026thinsp;22.6 mg/dL vs 101.7\u0026thinsp;\u0026plusmn;\u0026thinsp;16.8 mg/dL) compared to the non-periodontitis group, though these differences were not statistically significant (p\u0026thinsp;=\u0026thinsp;0.15 and p\u0026thinsp;=\u0026thinsp;0.14, respectively). The proportion of smokers was slightly higher in the periodontitis group (47 [54.0%] vs. 185 [48.7%], p\u0026thinsp;=\u0026thinsp;0.43). Furthermore, there was no significant difference in the number of untreated teeth between the periodontitis group and the non-periodontitis group (39 [44.8%] vs 142 [37.4%], p\u0026thinsp;=\u0026thinsp;0.24).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eHealthcare Expenditures\u003c/h3\u003e\n\u003cp\u003eAs presented in Table\u0026nbsp;2, participants with periodontitis group incurred significantly higher median annual medical expenditure (\u0026yen;41,160 vs \u0026yen;21,770, p\u0026thinsp;=\u0026thinsp;0.03), dental expenditure (\u0026yen;12,760 vs \u0026yen;7,030, p\u0026thinsp;=\u0026thinsp;0.01), and total healthcare expenditure (\u0026yen;97,030 vs \u0026yen;51,415; p\u0026thinsp;=\u0026thinsp;0.002). Although the median pharmaceutical expenditure was higher in the participants with periodontitis group, but the difference did not reach statistically significance (\u0026yen;14,000 vs \u0026yen;9,335, p\u0026thinsp;=\u0026thinsp;0.23)\u003c/p\u003e\n\u003ch3\u003eImpact of Baseline Periodontal Status on Long-Term Glycemic Trajectories\u003c/h3\u003e\n\u003cp\u003eThe trajectories of the adjusted mean HbA1c levels at baseline and during the 7-year follow-up period were illustrated in Figure. The MMRM analysis showed that, seven years later, these values were 5.69% (95% CI 5.62\u0026ndash;5.76) and 5.69% (95% CI 5.54\u0026ndash;5.84), respectively, with no statistically significant difference between the groups (difference of 0.07%, P\u0026thinsp;=\u0026thinsp;0.94). The association between baseline periodontitis status and subsequent increases in HbA1c using Cox proportional hazards models. For Outcome 1 (HbA1c\u0026thinsp;\u0026ge;\u0026thinsp;5.6%), 124 events occurred among 467 participants. The adjusted hazard ratio (HR) for participants with periodontitis compared with those without was 0.90 (95% CI: 0.62\u0026ndash;1.31, p\u0026thinsp;=\u0026thinsp;0.59). For Outcome 2 (HbA1c\u0026thinsp;\u0026ge;\u0026thinsp;6.5%), 27 events were observed, with an adjusted HR of 1.41 (95% CI: 0.65\u0026ndash;3.03, p\u0026thinsp;=\u0026thinsp;0.38) for participants with periodontitis. No statistically significant associations were observed between periodontitis status and increases in HbA1c in either outcome.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study investigated the relationship between periodontal disease and healthcare expenditures in a male working-age population in Japan. Our findings demonstrated that individuals with signs of periodontitis, defined by a community periodontal index (CPI) score of 3 or higher, incurred significantly higher annual medical expenditure, dental expenditure, and total healthcare expenditure compared to those without periodontitis. Although no statistically significant differences were observed in pharmaceutical expenditures, a consistent trend of elevated costs was evident in the periodontitis group, underscoring the potential economic burden associated with periodontal disease in this population.\u003c/p\u003e\u003cp\u003eThe link between periodontal health and systemic disease has been increasingly supported by a growing body of literature. For example, a large cohort study in Europe reported that improvements in oral hygiene care were associated with a reduction in cardiovascular disease risk, thereby suggesting that periodontal inflammation may contribute to systemic vascular dysfunction [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Furthermore, a recent editorial discussed the concept of \u0026ldquo;oral-systemic axis,\u0026rdquo;, emphasizing that periodontal disease may exacerbate metabolic and cardiovascular conditions through chronic low-grade inflammation [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Our findings reinforce these reports by demonstrating that employees with poorer periodontal status (CPI\u0026thinsp;\u0026ge;\u0026thinsp;3) incurred significantly higher medical expenditures, taken together, these data suggest that oral health not only influences systemic physiological parameters but also serves as an important causal factor for healthcare cost in working populations.\u003c/p\u003e\u003cp\u003eTherapeutic cost is another important outcome. Internationally, several studies have reported associations between poor oral health and increased healthcare costs. However, research specifically investigating this link within the Japanese context has been limited. Notably, Sato et al. reported that severe periodontitis was associated with increased inpatient and total medical expenditures among elderly adults aged 80 years, using periodontal inflamed surface area (PISA) as an indicator [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. More recently, Ichihashi et al. demonstrated that regular dental check-ups were associated with reduced cumulative medical and dental expenditures over a 12-year follow-up among employed adults, suggesting a preventive benefit of sustained oral care [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Furthermore, Kinugawa et al specifically reported that the co-existence of periodontitis and diabetes led to a significant increase in healthcare expenditures [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], indicating a profound economic impact of this \"oral-systemic axis.\" Our study expands the literature by focusing on a middle-aged workforce and demonstrating that not only dental expenditure but also medical expenditure and total healthcare expenditure were higher among individuals with clinical evidence of periodontitis. A significant finding of our study is the reporting of total healthcare expenditures, which underscores the broader economic implications of oral health status in working populations.\u003c/p\u003e\u003cp\u003eA related study by Masuko et al. demonstrated that the location of dental check-ups either conducted at the workplace or in external clinics, were significantly associated with absenteeism among Japanese workers [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Their findings underscore the relevance of access to preventive dental care in occupational settings. Our study complements this perspective by showing that both the accessibility of dental care and the actual periodontal health status, as reflected by CPI codes, may influence long-term healthcare expenditures. Together, these results suggested that promoting oral health within corporate health systems through both regular access and effective periodontal disease management could yield measurable benefits in terms of worker productivity and medical cost containment.\u003c/p\u003e\u003cp\u003eAs previously mentioned, the \u0026ldquo;oral-systemic axis\u0026rdquo; suggests that periodontal disease may exacerbate metabolic and cardiovascular conditions through chronic low-grade inflammation. Meta-analyses has substantiated a positive bidirectional association between periodontitis and diabetes mellitus [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Furthermore, recent research has demonstrated that infection with periodontal pathogens adversely affects gut microbiota health, condition leading to systemic insulin resistance and skeletal muscle metabolic dysfunction [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. While our analysis revealed a significant association between the presence of periodontal disease and higher medical, dental, and total healthcare expenditures, no statistically significant association was observed between baseline periodontal status and changes in glycemic parameters over the 7-year follow-up period. These findings suggested that in contrast to directly causing a clear deterioration in glycemic levels, periodontal disease may contribute to broader health issues and the associated increase in medical expenditures through undetected, chronic inflammation.\u003c/p\u003e\u003cp\u003eThis study has several limitations. First, as a retrospective cohort study, it could not establish a definitive causal relationship between periodontal disease and healthcare expenditures. A kind of personality such as laziness might be a cause of both dental and medical conditions. Second, the study was limited to health check-up and medical expenditure data. Consequently, detailed participant lifestyle factors (e.g., dietary habits, stress), genetic factors, or specific periodontal treatment details, which could act as confounding variables, may not have been fully captured, potentially influencing our results. Third, this study was conducted among employees of a single company group, limiting the generalizability of the findings. Fourth, the 7-year observation period might be relatively short, potentially insufficient for evaluating long-term effects. Finally, the lack of detailed oral health data (e.g., probing depth, attachment loss, or more specific periodontal tissue conditions) and data on specific oral hygiene behaviors also constrains the interpretation of our findings. Future studies using a prospective design with more comprehensive data on lifestyle factors and detailed oral health assessments is warranted.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, our findings demonstrated that periodontal disease is associated with a significant elevated in medical, dental, and total healthcare expenditures. These results highlight the importance of integrating oral health into corporate wellness programs as a cost-effective strategy to mitigate the overall healthcare burden.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eThe list of abbreviations is not provided, as all abbreviations used in this manuscript are defined upon first appearance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cp\u003e The need for written informed consent was waived by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241). Ethics Committee due to the retrospective nature of the study, which used anonymized data. All personal identifiers were removed before the researchers obtained the dataset from the Sunstar Group. The study protocol was approved by the Kyoto University Graduate School and Faculty of Medicine Ethics Committee (registration number: R3241) and was conducted in accordance with the principles of the Declaration of Helsinki.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent to publication\u003c/strong\u003e\u003cp\u003e All authors approved the final manuscript for publication.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis research did receive funding. Keiichi Matsuzaki received funding from Sunstar Foundation. The funding source did not influence the conduct of this work.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eK.M: Conceptualisation, Acquisition of data, Analysis and interpretation of data, Drafting of the manuscript, Critical revision of the paper for important intellectual content,Statistical analysis, Provision of study materials, Obtaining fundingT.S: Analysis and interpretation of data, Critical revision of the paper for important intellectual content, Statistical analysisT.K: Critical revision of the paper for important intellectual content, Provision of study materials, Obtaining funding, Supervision\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eOur sincere appreciation is extended to the participants for their invaluable contributions to the study.We are especially grateful to Mr. Shunya Kobayashi for his valuable support in data preparation and statistical analysis.We also thank Mr. Sato, Mr. Tanimizu, Ms. Takaine and our colleagues.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eListl S, Galloway J, Mossey PA, Marcenes W. Global Economic Impact of Dental Diseases. J Dent Res. 2015;94(10):1355\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEke PI, Thornton-Evans GO, Wei L, Borgnakke WS, Dye BA, Genco RJ. Periodontitis in US Adults: National Health and Nutrition Examination Survey 2009\u0026ndash;2014. J Am Dent Assoc. 2018;149(7):576\u0026ndash;e5886.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBorgnakke WS, Yl\u0026ouml;stalo PV, Taylor GW, Genco RJ. Effect of periodontal disease on diabetes: systematic review of epidemiologic observational evidence. J Periodontol. 2013;84(4 Suppl):S135\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDietrich T, Sharma P, Walter C, Weston P, Beck J. The epidemiological evidence behind the association between periodontitis and incident atherosclerotic cardiovascular disease. J Clin Periodontol. 2013;40(Suppl 14):S70\u0026ndash;84.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRyd\u0026eacute;n L, Buhlin K, Ekstrand E, de Faire U, Gustafsson A, Holmer J, et al. Periodontitis Increases the Risk of a First Myocardial Infarction: A Report From the PAROKRANK Study. Circulation. 2016;133(6):576\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNordendahl E, Gustafsson A, Norhammar A, N\u0026auml;sman P, Ryd\u0026eacute;n L, Kjellstr\u0026ouml;m B. PAROKRANK Steering Committee. Severe Periodontitis Is Associated with Myocardial Infarction in Females. J Dent Res. 2018;97(10):1114\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu Y, Qin H, Li T, Feng C, Han H, Cao Y, et al. Denture use and risk for cardiometabolic disease: observational and Mendelian randomization analyses. Eur J Prev Cardiol. 2024;31(1):13\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePark SY, Kim SH, Kang SH, Yoon CH, Lee HJ, Yun PY, et al. Improved oral hygiene care attenuates the cardiovascular risk of oral health disease: a population-based study from Korea. Eur Heart J. 2019;40(14):1138\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMauri-Obradors E, Elosua R. The oral-systemic axis: how oral health affects cardiovascular and metabolic health. Eur J Prev Cardiol. 2024;31(1):11\u0026ndash;2.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAlbert DA, Sadowsky D, Papapanou P, Conicella ML, Ward A. An examination of periodontal treatment and per member per month (PMPM) medical costs in an insured population. BMC Health Serv Res. 2006;6:103.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJeffcoat MK, Jeffcoat RL, Gladowski PA, Bramson JB, Blum JJ. Impact of periodontal therapy on general health: evidence from insurance data for five systemic conditions. Am J Prev Med. 2014;47(2):166\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSato M, Iwasaki M, Yoshihara A, Miyazaki H. Association between periodontitis and medical expenditure in older adults: A 33-month follow-up study. Geriatr Gerontol Int. 2016;16(7):856\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIchihashi T, Goto A, Myagmar-Ochir E, Haruyama Y, Muto T, Kobashi G. Association between the interval of worksite dental check-ups and dental and medical expenditures: a single-site, 12-year follow-up study in Japan. BMJ Open. 2022;12(10):e063658.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKinugawa A, Takeuchi K, Tamada Y, Kusama T, Sato M, Maeda M et al. Differences in health care expenditure due to the comorbidity status of periodontal disease and diabetes mellitus. J Periodontol. 2025 Jan 18.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMatsuzaki K, Taniguchi S, Inoue K, Kawamura T. Effectiveness of a healthcare retreat for male employees with cardiovascular risk factors. Prev Med Rep. 2018;13:170\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWorld Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013;310(20):2191\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMasuko S, Zaitsu T, Oshiro A, Ishimaru M, Aida J. Association between place of dental check-ups and work absenteeism among Japanese workers. J Occup Health. 2023 Jan-Dec;65(1):e12415.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSt\u0026ouml;hr J, Barbaresko J, Neuenschwander M, Schlesinger S. Bidirectional association between periodontal disease and diabetes mellitus: a systematic review and meta-analysis of cohort studies. Sci Rep. 2021;11(1):13686.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYamazaki K. Oral-gut axis as a novel biological mechanism linking periodontal disease and systemic diseases: A review. Jpn Dent Sci Rev. 2023;59:273\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"periodontitis, community periodontitis index, healthcare expenditure, annual health check-up","lastPublishedDoi":"10.21203/rs.3.rs-7813290/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7813290/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eThe global economic burden of dental diseases, particularly periodontitis, is substantial, with growing evidence linking these conditions to systemic diseases such as diabetes and cardiovascular diseases. Although international studies have demonstrated that periodontal treatment can mitigate medical costs, comprehensive research examining the relationship among oral health, healthcare expenditures, and systemic disease inset is still scarce, particularly in Japan. Therefore, this study examined the associations among oral health, medical and dental expenditures, and the incidence of lifestyle-related diseases, using annual health checkup data.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e This long-term cohort study analyzed data from 467 male employees who participated in annual health and dental check-ups from 2009-2014. Participants were categorized into periodontitis and non-periodontitis groups based on the community periodontal index. We compared baseline characteristics and healthcare expenditures (medical, dental, pharmaceutical and total healthcare) between two groups. Longitudinal changes in glycated hemoglobin (HbA1c) levels were evaluated using a mixed model for repeated measures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Participants in the periodontitis group (n=87) was significantly older than the non-periodontitis group (n=380). Median annual medical expenditure (¥41,160 vs ¥21,770; p=0.03), dental expenditure (¥12,760 vs ¥7,030; p=0.01), and total healthcare expenditure (¥97,030 vs ¥51,415; p=0.002) were significantly higher in the periodontitis group. No significant difference in HbA1c trajectories or the risk of exceeding an HbA1c threshold of 5.6% or 6.5% was observed between the two groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePoor periodontal health is associated with increased medical and dental expenditures. Promoting oral health in the workplace may be a cost-effective strategy for reducing the overall healthcare burden.\u003c/p\u003e","manuscriptTitle":"Periodontal Disease and Healthcare Expenditures: A 7-Year Cohort Study of Employees in Japan","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 09:15:21","doi":"10.21203/rs.3.rs-7813290/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-03T11:00:25+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-01T00:16:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-23T22:23:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111491173827957089197328626418454243929","date":"2025-11-08T21:49:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"207900792441733519893665348894134598446","date":"2025-11-07T11:37:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-06T20:30:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-05T08:01:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-04T16:34:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-11-04T15:38:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4d234021-54aa-4f2f-9d16-cc41e3ae3b71","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-01-10T03:08:11+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-19 09:15:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7813290","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7813290","identity":"rs-7813290","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}