Khat chewing, xerostomia, and unstimulated salivary flow among Yemeni adults: a cross-sectional comparative study using sialometry, the Clinical Oral Dryness Score (CODS), and the Summated Xerostomia Inventory (SXI-D)

Khat chewing, xerostomia, and unstimulated salivary flow among Yemeni adults: a cross-sectional comparative study using sialometry, the Clinical Oral Dryness Score (CODS), and the Summated Xerostomia Inventory (SXI-D) | 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 Khat chewing, xerostomia, and unstimulated salivary flow among Yemeni adults: a cross-sectional comparative study using sialometry, the Clinical Oral Dryness Score (CODS), and the Summated Xerostomia Inventory (SXI-D) Mohammed Bin Taja, Baleegh Al-kadasi, Manal Al-Hajri, Salah Hafedh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8462830/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objectives To evaluate the association between khat chewing and oral dryness among Yemeni adults using clinical (Clinical Oral Dryness Score; CODS), symptom-based xerostomia assessment (Summated Xerostomia Inventory–Dutch Version; SXI-D), and unstimulated salivary flow rate (uSFR) outcomes. Materials and Methods In this clinic-based cross-sectional comparative study (n = 200), participants were classified as khat chewers (n = 171) or non-chewers (n = 29). CODS (1–10) and xerostomia symptoms (SXI-D; 5–15) were assessed at baseline. Unstimulated saliva was collected by the spitting method over 15 minutes, and uSFR (mL/min) was calculated. Among chewers, uSFR was additionally measured immediately before and after a typical khat session (paired assessment). Results Most participants had mild-to-moderate clinical dryness (CODS 1–3: 49.5%; CODS 4–6: 45.5%), with 5.0% classified as severe (CODS 7–10). Mean baseline uSFR was lower in chewers than non-chewers (0.387 vs 0.445 mL/min). Among chewers, mean uSFR decreased from 0.395 mL/min pre-session to 0.229 mL/min post-session (p < 0.001). Xerostomia symptoms were common; 39.5% reported a dry mouth on a single-item screen. Conclusions Khat chewing was associated with reduced unstimulated salivary flow and frequent oral dryness in this Yemeni adult cohort, and salivary flow decreased substantially after a typical chewing session. Clinical Relevance: Oral health providers in khat-prevalent settings should screen for xerostomia and counsel chewers on hydration, caries risk mitigation, and symptom management, especially following prolonged sessions. khat xerostomia unstimulated salivary flow CODS SXI-D Yemen Figures Figure 1 Figure 2 Figure 3 Introduction Khat (Catha edulis) chewing remains a widely practiced social habit in Yemen and the Horn of Africa, with surveys indicating high prevalence particularly among men [ 1 – 4 , 32 , 33 , 37 , 39 ]. The leaves contain the alkaloids cathinone and cathine, which have amphetamine-like sympathomimetic properties [ 36 – 38 ]. While cultural and social functions of khat sessions are well recognized, accumulating evidence links habitual chewing to a spectrum of oral conditions, including mucosal changes, periodontal disease, and alterations in salivary properties such as pH, viscosity, and flow [ 5 – 10 ]. Xerostomia (subjective dry mouth) and hyposalivation (objectively reduced salivary flow) are related but distinct constructs that substantially impact oral comfort, speech, mastication, taste, swallowing, denture retention, caries risk, and candidiasis [ 11 – 13 , 19 – 23 , 40 ]. Unstimulated whole salivary flow rate (uSFR) thresholds of approximately 0.1–0.2 mL/min are commonly used to operationalize hyposalivation, with values below ≈ 0.1 mL/min associated with markedly increased risk of oral complications [ 11 – 13 , 21 ]. The Clinical Oral Dryness Score (CODS) is a 10-item clinician-rated scale (0–10) that captures observable signs of oral dryness and correlates with sialometric findings and symptom inventories [ 11 , 12 , 23 – 26 ]. Despite Yemen’s high burden of khat exposure, contemporary, clinic-based data that quantify the acute impact of chewing on unstimulated secretory function using standardized sialometry, together with a validated clinical dryness index, remain scarce. Moreover, symptom questionnaires can over- or under-estimate xerostomia in populations where beverage intake (tea, coffee) and session-related behaviors may transiently modify oral moisture [ 13 , 34 ]. To address these gaps, we investigated unstimulated whole salivary flow and CODS findings in working-age adults attending university dental clinics in Sana’a, comparing khat-chewers with non-chewers and characterizing within-chewer pre/post-session changes. Based on the sympathomimetic profile of cathinone and prior observational reports, we hypothesized that khat sessions would be associated with an immediate reduction in unstimulated salivary flow, and that objective clinical signs of oral dryness would be common among regular chewers [ 5 – 10 , 36 – 38 ]. Methods Study design and setting: We conducted a clinic-based cross-sectional comparative study with a nested within-subject pre–post assessment among khat chewers. Participants were recruited from Sana’a University dental clinics between July 2019 and December 2021. Participants: Adults aged 16–50 years attending the university dental clinics were invited to participate. Participants were classified as khat chewers or non-chewers based on self-reported khat use. The sample size reflected a pragmatic clinic-based recruitment target intended to (i) estimate the prevalence of clinical oral dryness and xerostomia symptoms and (ii) detect within-chewer pre–post changes in unstimulated salivary flow; between-group comparisons were considered exploratory given the imbalance between groups. Ethical considerations: Written informed consent was obtained from all participants. For participants aged 16–17 years, consent procedures followed local regulations and the approving ethics committee requirements. The protocol received institutional ethical approval prior to recruitment and was conducted in accordance with the Declaration of Helsinki. Measures: Clinical oral dryness was assessed using the Clinical Oral Dryness Score (CODS; 10-item clinical scale; total 0–10, higher scores indicating greater dryness). Subjective xerostomia symptoms were assessed using the Summated Xerostomia Inventory–Dutch Version (SXI-D), a five-item questionnaire with three response categories per item (Never = 1, Occasionally = 2, Ever = 3; total score 5–15). An Arabic version was produced by translation and back-translation of the SXI-D items for use among Yemeni adults. Unstimulated whole saliva was collected by the spitting method with participants seated upright. Chewers provided samples immediately before and immediately after a typical khat session; non-chewers provided a single baseline sample. Statistical analysis: Descriptive statistics summarized participant characteristics, khat use, salivary flow, CODS, and xerostomia symptoms. Within-chewer pre–post changes in salivary flow were evaluated using paired tests (paired t-test or Wilcoxon signed-rank, as appropriate). Between-group comparisons at baseline (chewers vs non-chewers) were evaluated using independent-samples tests (Welch’s t-test or Mann–Whitney U) for continuous variables and χ²/Fisher’s exact test for categorical variables. We report mean differences (or median differences) and p-values. Multivariable adjustment was not performed because key confounders were not uniformly available in the study dataset. Results Participant characteristics: Two hundred adults were enrolled; 148 (74.0%) were male and 52 (26.0%) female, with a mean age of 26.37 years (range 16–50). Khat chewing was reported by 171 participants (85.5%); 125 were daily chewers. Participant characteristics and khat-use patterns are summarized in Table 1 . Table 1 Participant characteristics and khat chewing status Characteristic Value Sample size (n) 200 Mean age (years) 26.37 Age range (years) 16–50 Male n (%) 148 (74.0%) Female n (%) 52 (26.0%) Khat chewing: Yes 171 (85.5%) Khat chewing: No 29 (14.5%) Daily consumers (subset) 125 (62.5%) Key study outcomes are summarized in Table 2 (unstimulated salivary flow outcomes) and Table 4 (xerostomia symptom item responses). Table 2 Unstimulated salivary flow rate (uSFR) outcomes Comparison Mean total flow (15 min), mL Mean uSFR, mL/min Notes Baseline (non-chewers) 6.67 0.445 Single baseline collection Baseline (chewers, pre-session) 5.80 0.387 Before khat session Chewers (post-session) 3.45 0.230 Immediately after khat session Chewers: Before Khat chewing 5.93 0.395 Paired comparison p < 0.001 (as reported) Chewers: After Khat chewing 3.43 0.229 Paired comparison p < 0.001 (as reported) Table 4 Xerostomia symptoms (SXI-D item responses) Item Never n Never % Occasionally n Occasionally % Ever n Ever % My mouth feels dry when eating a meal. 71 38 93 49.7 23 12.3 My mouth feels dry. 35 18.8 129 69.4 22 11.8 I have difficulty in eating dry foods. 39 21 105 56.5 42 22.6 I have difficulties swallowing certain foods. 85 45.9 81 43.8 19 10.3 My lips feel dry. 39 21 103 55.4 44 23.7 Abbreviations: CODS, Clinical Oral Dryness Score; uSFR, unstimulated salivary flow rate; SXI-D, Summated Xerostomia Inventory–Dutch Version. Unstimulated salivary flow and xerostomia symptoms: Among khat chewers, the 15‑minute unstimulated saliva volume decreased from 5.93 mL before a typical khat session to 3.43 mL after the session (0.395 to 0.229 mL/min). Baseline unstimulated saliva volumes were numerically lower in chewers than non-chewers, but period-specific baseline differences were not statistically significant in summary analyses. Xerostomia symptom burden (SXI-D) did not differ between chewers and non-chewers (mean ± SD 9.33 ± 1.96 vs 9.52 ± 1.91; p = 0.638). Clinical oral dryness: Across the full cohort (n = 200), CODS grading indicated mild dryness in 49.5%, moderate dryness in 45.5%, and severe dryness in 5.0% of participants (Table 3 ). Symptom questionnaires showed broad endorsement of ‘occasional’ dryness-related items—particularly dryness during meals and upon waking—consistent with limited diagnostic specificity of symptom-only screening in this population and the value of objective measures. Table 3 Clinical Oral Dryness Score (CODS) distribution CODS category Severity n % 1–3 Mild xerostomia 99 49.5 4–6 Moderate xerostomia 91 45.5 7–10 Severe xerostomia 10 5.0 Ancillary observations: Consistent scheduling minimized circadian variability, and unstimulated collections were completed before any procedures that could stimulate flow. Questionnaire data suggested frequent co-consumption of tea/coffee during chewing sessions, which merits attention in future analyses. Discussion Limitations Because participant-level raw data were not retained, analyses are limited to the aggregate results reported in the original thesis (e.g., no multivariable regression or correlation analyses). Principal findings: In a university-clinic cohort from Sana’a, khat chewing was associated with a large acute reduction in unstimulated salivary flow (≈ 42% decline in uSFR from 0.395 to 0.229 mL/min) and a high prevalence of objective signs of oral dryness as captured by CODS. These results substantiate clinical impressions that regular chewers frequently exhibit salivary hypofunction around sessions and underscore the importance of objective chairside assessment in high-prevalence settings. Context with prior literature: Reviews and observational studies have linked khat to oral mucosal changes, periodontal inflammation, and altered salivary properties, including decreased pH and modified viscosity [ 5 – 10 ]. Our data complement these findings by quantifying immediate changes in unstimulated secretion using standardized protocols. Given accepted hyposalivation thresholds (≈ 0.1–0.2 mL/min) [ 11 – 13 , 21 ], post-session means near 0.23 mL/min approach clinically important ranges, particularly for individuals with comorbid risk factors (polypharmacy, autoimmune disease, diabetes) [ 19 – 23 ]. Physiologic considerations: Cathinone’s sympathomimetic activity may influence salivary gland vasculature and acinar function, while session behaviors (prolonged unilateral mastication, reduced water intake, and concurrent caffeine use) may compound dehydrating effects [ 36 – 38 ]. Although stimulated salivary flow may transiently increase with mastication, the observed suppression in unstimulated output post-session aligns with autonomic modulation and behavioral fluid balance shifts. Time-course studies are warranted to clarify recovery dynamics over several hours and the cumulative impact of daily chewing. Clinical implications: Routine chairside screening can integrate three steps: [ 1 ] brief intake on khat frequency/duration and co-use (tobacco, tea/coffee), [ 2 ] CODS scoring (0–10), and [ 3 ] a 5–10-minute unstimulated collection to estimate uSFR. Management should focus on etiologic counseling, hydration strategies, sugar-free/xylitol chewing gum or lozenges, topical fluoride and remineralizing agents, high-fluoride toothpaste, and saliva substitutes where needed [ 19 – 23 ]. Medication review is advisable for xerogenic drugs (anticholinergics, antidepressants, antihypertensives), and denture wearers may benefit from fit optimization and nighttime relining regimens. Preventive recall can be individualized for patients whose post-session uSFR suggests elevated caries or candidiasis risk. Public-health and regional considerations: Yemen’s high prevalence of chewing among men and substantial use among women [ 1 – 4 , 32 , 33 , 37 , 39 ] imply a large population at risk for xerostomia-related morbidity [ 40 ]. Embedding simple UWS protocols and CODS scoring into public and university dental clinics could facilitate early identification and tailored prevention. Health-promotion messaging may integrate oral-health consequences with broader cardiometabolic risks associated with chronic khat use [ 35 – 38 ]. Strengths and limitations: Strengths include use of standardized unstimulated sialometry, a validated clinical dryness index, and pre/post assessment in chewers. Limitations include the single-center design, lack of long-term follow-up, and residual confounding despite exclusions (dietary patterns, fluid intake, unmeasured medications). Symptom questionnaires exhibited broad ‘occasional’ endorsements, consistent with prior observations that symptoms alone are insufficiently specific in mixed-exposure settings [ 13 , 24 – 26 , 34 ]. Future directions: Prospective, multicenter cohorts should stratify by chewing intensity and duration, beverage co-consumption, baseline hydration, and medication use, while extending observations over 24–48 hours to map recovery of basal secretion. Intervention trials could evaluate the effectiveness of targeted preventive bundles (xylitol + high-fluoride toothpaste + remineralizing agents + hydration counseling) for reducing caries incidence, candidiasis, and patient-reported dry-mouth burden. Conclusions Khat chewing among Yemeni adults was associated with a large acute suppression of unstimulated salivary flow and a high prevalence of clinician-observed oral dryness. Objective screening using CODS and brief unstimulated sialometry can be implemented rapidly within routine care to identify at-risk individuals and guide preventive management in high-prevalence communities. Declarations Compliance with Ethical Standards Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki and relevant institutional guidelines. The research protocol was reviewed and approved by the Medical Ethics Committee of the Faculty of Dentistry, Sana’a University, Sana’a, Yemen (approval reference OMPR:05/12/2024). All participants were aged 16 years or older; no individuals younger than 16 years were enrolled. All participants were capable of providing informed consent and provided oral and written informed consent before participation. Consent for publication: Not applicable (no identifying personal data or images are included). Funding: No external funding was received for this study. Supplementary material: The questionnaire and case-record form are provided as Online Resource 1. Author Contribution MBT and BK conceived and designed the study. MBT and MH collected data and performed clinical assessments. SH oversaw analysis and led manuscript drafting. All authors interpreted data, critically revised the manuscript, and approved the final version. 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Subst Abuse Treat Prev Policy. ;10:17. Available at: https://doi.org/10.1186/s13011-015-0018-3 Abdullah MJ (2015) Prevalence of xerostomia in adults. J Clin Exp Dent. ;7:e45–e53. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC4349822/ van der Thomson WMde Baat CIkebe KMatsuda KEnoki KHopcraft MSLing GY (2011) Shortening the xerostomia inventory. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1123:322–327. 10.1016/j.tripleo.2011.03.024 Clinical trial registration: Not applicable (observational study; not a clinical trial) Additional Declarations No competing interests reported. Supplementary Files Questionnaire.pdf MedicalEthicsCommitteeApproval.pdf Cite Share Download PDF Status: Posted Version 1 posted 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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23:49:22","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":120966,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig1.png","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/d38b3f3315374e3956b3d610.png"},{"id":99651457,"identity":"56f236c1-7d60-4544-912b-8eb7e8c15e69","added_by":"auto","created_at":"2026-01-06 23:49:22","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":126726,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFig2.png","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/bb2d1a11e18d913089ca7cc3.png"},{"id":99795165,"identity":"b5975f5d-b245-4218-a68e-bdefe6a54be1","added_by":"auto","created_at":"2026-01-08 13:37:08","extension":"xml","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":73291,"visible":true,"origin":"","legend":"","description":"","filename":"9eba6e96aff1423386f8b80dd8f9e8b71structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/6bd3fecf744e296e1baaeb01.xml"},{"id":99796089,"identity":"f0002438-6e09-4176-8745-e4e26aac46b6","added_by":"auto","created_at":"2026-01-08 13:40:26","extension":"html","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":92825,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/f44872abb6149b78358c1a0e.html"},{"id":99651441,"identity":"1a18a2ed-7c05-4f5f-8bb2-83dee24d8885","added_by":"auto","created_at":"2026-01-06 23:49:21","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":339329,"visible":true,"origin":"","legend":"\u003cp\u003eClinical Oral Dryness Score (CODS) distribution in the study cohort (n=200).\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/3fe8bca4d07fbaf0ede20467.jpg"},{"id":99794174,"identity":"8dd8bf9a-4cd1-47bd-a554-33d47ecfad4b","added_by":"auto","created_at":"2026-01-08 13:34:10","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":437909,"visible":true,"origin":"","legend":"\u003cp\u003eUnstimulated salivary flow rate (uSFR) before and after a khat chewing session among khat chewers (n=171). Bars show mean uSFR (mL/min).\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/96736b2c01581dea49a69bc0.jpg"},{"id":99794547,"identity":"482537b0-9207-49b8-ad41-b1ee3123f945","added_by":"auto","created_at":"2026-01-08 13:35:20","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":331526,"visible":true,"origin":"","legend":"\u003cp\u003eKhat chewing status in the study cohort (n=200).\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/dd168e3bace2f2d765425fa4.jpg"},{"id":99805056,"identity":"0812d5d1-530a-4777-8081-0c61009312c3","added_by":"auto","created_at":"2026-01-08 14:15:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1713857,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/e4ebe43f-ac33-4fd0-8fcc-0d05e905d9d3.pdf"},{"id":99651447,"identity":"bea76d61-ab9e-4ca4-b558-a27aab9c6447","added_by":"auto","created_at":"2026-01-06 23:49:22","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":750617,"visible":true,"origin":"","legend":"","description":"","filename":"Questionnaire.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/2b389d4260c247b32371608e.pdf"},{"id":99795652,"identity":"b8bae50d-d32d-4848-ae98-b53b3f6aea7e","added_by":"auto","created_at":"2026-01-08 13:39:08","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1461293,"visible":true,"origin":"","legend":"","description":"","filename":"MedicalEthicsCommitteeApproval.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8462830/v1/f0816166ae33c201045ebe51.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Khat chewing, xerostomia, and unstimulated salivary flow among Yemeni adults: a cross-sectional comparative study using sialometry, the Clinical Oral Dryness Score (CODS), and the Summated Xerostomia Inventory (SXI-D)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eKhat (Catha edulis) chewing remains a widely practiced social habit in Yemen and the Horn of Africa, with surveys indicating high prevalence particularly among men [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. The leaves contain the alkaloids cathinone and cathine, which have amphetamine-like sympathomimetic properties [\u003cspan additionalcitationids=\"CR37\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. While cultural and social functions of khat sessions are well recognized, accumulating evidence links habitual chewing to a spectrum of oral conditions, including mucosal changes, periodontal disease, and alterations in salivary properties such as pH, viscosity, and flow [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eXerostomia (subjective dry mouth) and hyposalivation (objectively reduced salivary flow) are related but distinct constructs that substantially impact oral comfort, speech, mastication, taste, swallowing, denture retention, caries risk, and candidiasis [\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR20 CR21 CR22\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Unstimulated whole salivary flow rate (uSFR) thresholds of approximately 0.1\u0026ndash;0.2 mL/min are commonly used to operationalize hyposalivation, with values below \u0026asymp;\u0026thinsp;0.1 mL/min associated with markedly increased risk of oral complications [\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The Clinical Oral Dryness Score (CODS) is a 10-item clinician-rated scale (0\u0026ndash;10) that captures observable signs of oral dryness and correlates with sialometric findings and symptom inventories [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite Yemen\u0026rsquo;s high burden of khat exposure, contemporary, clinic-based data that quantify the acute impact of chewing on unstimulated secretory function using standardized sialometry, together with a validated clinical dryness index, remain scarce. Moreover, symptom questionnaires can over- or under-estimate xerostomia in populations where beverage intake (tea, coffee) and session-related behaviors may transiently modify oral moisture [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. To address these gaps, we investigated unstimulated whole salivary flow and CODS findings in working-age adults attending university dental clinics in Sana\u0026rsquo;a, comparing khat-chewers with non-chewers and characterizing within-chewer pre/post-session changes.\u003c/p\u003e \u003cp\u003eBased on the sympathomimetic profile of cathinone and prior observational reports, we hypothesized that khat sessions would be associated with an immediate reduction in unstimulated salivary flow, and that objective clinical signs of oral dryness would be common among regular chewers [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan additionalcitationids=\"CR37\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e "},{"header":"Methods","content":" \u003cp\u003eStudy design and setting: We conducted a clinic-based cross-sectional comparative study with a nested within-subject pre\u0026ndash;post assessment among khat chewers. Participants were recruited from Sana\u0026rsquo;a University dental clinics between July 2019 and December 2021.\u003c/p\u003e \u003cp\u003eParticipants: Adults aged 16\u0026ndash;50 years attending the university dental clinics were invited to participate. Participants were classified as khat chewers or non-chewers based on self-reported khat use. The sample size reflected a pragmatic clinic-based recruitment target intended to (i) estimate the prevalence of clinical oral dryness and xerostomia symptoms and (ii) detect within-chewer pre\u0026ndash;post changes in unstimulated salivary flow; between-group comparisons were considered exploratory given the imbalance between groups.\u003c/p\u003e \u003cp\u003e Ethical considerations: Written informed consent was obtained from all participants. For participants aged 16\u0026ndash;17 years, consent procedures followed local regulations and the approving ethics committee requirements. The protocol received institutional ethical approval prior to recruitment and was conducted in accordance with the Declaration of Helsinki.\u003c/p\u003e \u003cp\u003e Measures: Clinical oral dryness was assessed using the Clinical Oral Dryness Score (CODS; 10-item clinical scale; total 0\u0026ndash;10, higher scores indicating greater dryness). Subjective xerostomia symptoms were assessed using the Summated Xerostomia Inventory\u0026ndash;Dutch Version (SXI-D), a five-item questionnaire with three response categories per item (Never\u0026thinsp;=\u0026thinsp;1, Occasionally\u0026thinsp;=\u0026thinsp;2, Ever\u0026thinsp;=\u0026thinsp;3; total score 5\u0026ndash;15). An Arabic version was produced by translation and back-translation of the SXI-D items for use among Yemeni adults. Unstimulated whole saliva was collected by the spitting method with participants seated upright. Chewers provided samples immediately before and immediately after a typical khat session; non-chewers provided a single baseline sample.\u003c/p\u003e \u003cp\u003e Statistical analysis: Descriptive statistics summarized participant characteristics, khat use, salivary flow, CODS, and xerostomia symptoms. Within-chewer pre\u0026ndash;post changes in salivary flow were evaluated using paired tests (paired t-test or Wilcoxon signed-rank, as appropriate). Between-group comparisons at baseline (chewers vs non-chewers) were evaluated using independent-samples tests (Welch\u0026rsquo;s t-test or Mann\u0026ndash;Whitney U) for continuous variables and χ\u0026sup2;/Fisher\u0026rsquo;s exact test for categorical variables. We report mean differences (or median differences) and p-values. Multivariable adjustment was not performed because key confounders were not uniformly available in the study dataset.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eParticipant characteristics: Two hundred adults were enrolled; 148 (74.0%) were male and 52 (26.0%) female, with a mean age of 26.37 years (range 16\u0026ndash;50). Khat chewing was reported by 171 participants (85.5%); 125 were daily chewers. Participant characteristics and khat-use patterns are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParticipant characteristics and khat chewing status\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample size (n)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean age (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge range (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u0026ndash;50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e148 (74.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52 (26.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKhat chewing: Yes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e171 (85.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKhat chewing: No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e29 (14.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDaily consumers (subset)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e125 (62.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eKey study outcomes are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (unstimulated salivary flow outcomes) and Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e4\u003c/span\u003e (xerostomia symptom item responses).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eUnstimulated salivary flow rate (uSFR) outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComparison\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean total flow (15 min), mL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean uSFR, mL/min\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNotes\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBaseline (non-chewers)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.445\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSingle baseline collection\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBaseline (chewers, pre-session)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.387\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBefore khat session\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChewers (post-session)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.230\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImmediately after khat session\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChewers: Before Khat chewing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.395\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePaired comparison p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 (as reported)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChewers: After Khat chewing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.229\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePaired comparison p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 (as reported)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eXerostomia symptoms (SXI-D item responses)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eItem\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNever n\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNever %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOccasionally n\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOccasionally %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEver n\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eEver %\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMy mouth feels dry when eating a meal.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e49.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e12.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMy mouth feels dry.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e129\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e69.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e11.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eI have difficulty in eating dry foods.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e56.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e22.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eI have difficulties swallowing certain foods.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e45.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e43.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMy lips feel dry.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e103\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e55.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e23.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eAbbreviations: CODS, Clinical Oral Dryness Score; uSFR, unstimulated salivary flow rate; SXI-D, Summated Xerostomia Inventory\u0026ndash;Dutch Version.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eUnstimulated salivary flow and xerostomia symptoms: Among khat chewers, the 15‑minute unstimulated saliva volume decreased from 5.93 mL before a typical khat session to 3.43 mL after the session (0.395 to 0.229 mL/min). Baseline unstimulated saliva volumes were numerically lower in chewers than non-chewers, but period-specific baseline differences were not statistically significant in summary analyses. Xerostomia symptom burden (SXI-D) did not differ between chewers and non-chewers (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD 9.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96 vs 9.52\u0026thinsp;\u0026plusmn;\u0026thinsp;1.91; p\u0026thinsp;=\u0026thinsp;0.638).\u003c/p\u003e \u003cp\u003eClinical oral dryness: Across the full cohort (n\u0026thinsp;=\u0026thinsp;200), CODS grading indicated mild dryness in 49.5%, moderate dryness in 45.5%, and severe dryness in 5.0% of participants (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Symptom questionnaires showed broad endorsement of \u0026lsquo;occasional\u0026rsquo; dryness-related items\u0026mdash;particularly dryness during meals and upon waking\u0026mdash;consistent with limited diagnostic specificity of symptom-only screening in this population and the value of objective measures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical Oral Dryness Score (CODS) distribution\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCODS category\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSeverity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMild xerostomia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e49.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u0026ndash;6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate xerostomia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e45.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u0026ndash;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSevere xerostomia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAncillary observations: Consistent scheduling minimized circadian variability, and unstimulated collections were completed before any procedures that could stimulate flow. Questionnaire data suggested frequent co-consumption of tea/coffee during chewing sessions, which merits attention in future analyses.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eLimitations\u003c/p\u003e \u003cp\u003eBecause participant-level raw data were not retained, analyses are limited to the aggregate results reported in the original thesis (e.g., no multivariable regression or correlation analyses).\u003c/p\u003e \u003cp\u003e Principal findings: In a university-clinic cohort from Sana\u0026rsquo;a, khat chewing was associated with a large acute reduction in unstimulated salivary flow (\u0026asymp;\u0026thinsp;42% decline in uSFR from 0.395 to 0.229 mL/min) and a high prevalence of objective signs of oral dryness as captured by CODS. These results substantiate clinical impressions that regular chewers frequently exhibit salivary hypofunction around sessions and underscore the importance of objective chairside assessment in high-prevalence settings.\u003c/p\u003e \u003cp\u003eContext with prior literature: Reviews and observational studies have linked khat to oral mucosal changes, periodontal inflammation, and altered salivary properties, including decreased pH and modified viscosity [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Our data complement these findings by quantifying immediate changes in unstimulated secretion using standardized protocols. Given accepted hyposalivation thresholds (\u0026asymp;\u0026thinsp;0.1\u0026ndash;0.2 mL/min) [\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], post-session means near 0.23 mL/min approach clinically important ranges, particularly for individuals with comorbid risk factors (polypharmacy, autoimmune disease, diabetes) [\u003cspan additionalcitationids=\"CR20 CR21 CR22\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePhysiologic considerations: Cathinone\u0026rsquo;s sympathomimetic activity may influence salivary gland vasculature and acinar function, while session behaviors (prolonged unilateral mastication, reduced water intake, and concurrent caffeine use) may compound dehydrating effects [\u003cspan additionalcitationids=\"CR37\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Although stimulated salivary flow may transiently increase with mastication, the observed suppression in unstimulated output post-session aligns with autonomic modulation and behavioral fluid balance shifts. Time-course studies are warranted to clarify recovery dynamics over several hours and the cumulative impact of daily chewing.\u003c/p\u003e \u003cp\u003eClinical implications: Routine chairside screening can integrate three steps: [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] brief intake on khat frequency/duration and co-use (tobacco, tea/coffee), [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] CODS scoring (0\u0026ndash;10), and [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] a 5\u0026ndash;10-minute unstimulated collection to estimate uSFR. Management should focus on etiologic counseling, hydration strategies, sugar-free/xylitol chewing gum or lozenges, topical fluoride and remineralizing agents, high-fluoride toothpaste, and saliva substitutes where needed [\u003cspan additionalcitationids=\"CR20 CR21 CR22\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Medication review is advisable for xerogenic drugs (anticholinergics, antidepressants, antihypertensives), and denture wearers may benefit from fit optimization and nighttime relining regimens. Preventive recall can be individualized for patients whose post-session uSFR suggests elevated caries or candidiasis risk.\u003c/p\u003e \u003cp\u003ePublic-health and regional considerations: Yemen\u0026rsquo;s high prevalence of chewing among men and substantial use among women [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] imply a large population at risk for xerostomia-related morbidity [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Embedding simple UWS protocols and CODS scoring into public and university dental clinics could facilitate early identification and tailored prevention. Health-promotion messaging may integrate oral-health consequences with broader cardiometabolic risks associated with chronic khat use [\u003cspan additionalcitationids=\"CR36 CR37\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStrengths and limitations: Strengths include use of standardized unstimulated sialometry, a validated clinical dryness index, and pre/post assessment in chewers. Limitations include the single-center design, lack of long-term follow-up, and residual confounding despite exclusions (dietary patterns, fluid intake, unmeasured medications). Symptom questionnaires exhibited broad \u0026lsquo;occasional\u0026rsquo; endorsements, consistent with prior observations that symptoms alone are insufficiently specific in mixed-exposure settings [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFuture directions: Prospective, multicenter cohorts should stratify by chewing intensity and duration, beverage co-consumption, baseline hydration, and medication use, while extending observations over 24\u0026ndash;48 hours to map recovery of basal secretion. Intervention trials could evaluate the effectiveness of targeted preventive bundles (xylitol\u0026thinsp;+\u0026thinsp;high-fluoride toothpaste\u0026thinsp;+\u0026thinsp;remineralizing agents\u0026thinsp;+\u0026thinsp;hydration counseling) for reducing caries incidence, candidiasis, and patient-reported dry-mouth burden.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003e Khat chewing among Yemeni adults was associated with a large acute suppression of unstimulated salivary flow and a high prevalence of clinician-observed oral dryness. Objective screening using CODS and brief unstimulated sialometry can be implemented rapidly within routine care to identify at-risk individuals and guide preventive management in high-prevalence communities.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompliance with Ethical Standards\u003c/h2\u003e \u003cp\u003e Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki and relevant institutional guidelines. The research protocol was reviewed and approved by the Medical Ethics Committee of the Faculty of Dentistry, Sana\u0026rsquo;a University, Sana\u0026rsquo;a, Yemen (approval reference OMPR:05/12/2024). All participants were aged 16 years or older; no individuals younger than 16 years were enrolled. All participants were capable of providing informed consent and provided oral and written informed consent before participation.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication:\u003c/strong\u003e \u003cp\u003eNot applicable (no identifying personal data or images are included).\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eNo external funding was received for this study.\u003c/p\u003e \u003cp\u003eSupplementary material: The questionnaire and case-record form are provided as Online Resource 1.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMBT and BK conceived and designed the study. MBT and MH collected data and performed clinical assessments. SH oversaw analysis and led manuscript drafting. All authors interpreted data, critically revised the manuscript, and approved the final version.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e \u003cp\u003eWe thank the staff and patients of the Sana\u0026rsquo;a University dental clinics for their cooperation.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eParticipant-level raw data are not publicly available. Aggregate summary data used for the figures and tables are provided in the accompanying tables and supplementary files; additional details are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWorld Bank. Yemen: Toward Qat Demand Reduction? 2007 (summary article 2014). Available at: https://documents.worldbank.org(accessed 11 Nov 2025)\u003c/li\u003e\n\u003cli\u003eAl-Eryani S Yemen’s Qat Addiction Worsens. World Bank Blogs. 2014 Mar 20. Available at: https://blogs.worldbank.org\u003c/li\u003e\n\u003cli\u003eNakajima M et al (2012) Gender differences in patterns and correlates of khat and tobacco use. Nicotine Tob Res. ;14[10]:1242–1247. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC3646654/\u003c/li\u003e\n\u003cli\u003eNakajima M et al (2014) Habitual khat and concurrent khat and tobacco use. Prev Chronic Dis. ;11:E117. Available at: https://www.cdc.gov/pcd/issues/2014/13_0234.htm\u003c/li\u003e\n\u003cli\u003eAl-Maweri SA et al (2018) Khat and oral health: an updated review. Int Dent J. Available at: https://onlinelibrary.wiley.com/doi/abs/10.1111/idj.12402\u003c/li\u003e\n\u003cli\u003eAl-Alimi A et al (2014) Effects of khat chewing on saliva compositionpHand flow rate. Available at: https://eprints.uob.edu.ly/items/f708103f-6a5b-4245-9711-9ebef6988393/1/ssrn-id2529630%20[1].pdf\u003c/li\u003e\n\u003cli\u003eBadulla W et al (2019) Effect of khat chewing on salivary pH among adults. Evid Based Complement Alternat Med. ;2019:7097972. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6904976/\u003c/li\u003e\n\u003cli\u003eSilva P et al (2022) Khat: bundle of toxins? Toxins (Basel). ;14[5]:332. Available at: https://www.mdpi.com/2072-6651/14/5/332\u003c/li\u003e\n\u003cli\u003eAl-Akw’a OA et al (2025) Taste thresholds among khat chewers. Oral Surg Oral Med Oral Pathol Oral Radiol. Available at: https://www.oooojournal.net/article/S2212-4403[24]00446-4/fulltext\u003c/li\u003e\n\u003cli\u003eYarom N et al (2010) Oral manifestations of habitual khat chewing. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 109:e60–e66\u003c/li\u003e\n\u003cli\u003eOsailan SM et al (2012) Clinical assessment of oral dryness: development of a scoring system (CODS). Oral Surg Oral Med Oral Pathol Oral Radiol. ;114:597–603. 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Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC1331668/\u003c/li\u003e\n\u003cli\u003eBellagambi FG et al (2020) Saliva sampling: methods and devices. TrAC Trends Anal Chem. ;124:115781. Available at: https://www.sciencedirect.com/science/article/am/pii/S0165993619304182\u003c/li\u003e\n\u003cli\u003eForcella L et al (2018) Measurement of unstimulated salivary flow rate. Swiss Dent J. ;128:318–324. Available at: https://www.swissdentaljournal.org/article/view/5581/4179\u003c/li\u003e\n\u003cli\u003eRoyal Australian College of General Practitioners. Xerostomia — a clinical update (2016) Available at: https://www.racgp.org.au/afp/2016/december/xerostomia\u003c/li\u003e\n\u003cli\u003eNational Cancer Institute PDQ Oral Complications of Cancer Treatment — Xerostomia. Updated 2023. Available at: https://www.cancer.gov/about-cancer/treatment/side-effects/xerostomia-hp-pdq\u003c/li\u003e\n\u003cli\u003eAlvariño JMR et al (2021) Salivary gland flow rates and thresholds revisited. Med Oral Patol Oral Cir Bucal. ;26:e63–e72. Available at: https://pubmed.ncbi.nlm.nih.gov/32755053/\u003c/li\u003e\n\u003cli\u003eKapourani A et al (2022) Xerostomia and hyposalivation: mechanisms and management. Polymers (Basel). ;14:1434. Available at: https://www.mdpi.com/2073-4360/14/7/1434\u003c/li\u003e\n\u003cli\u003eHijjaw O et al (2019) Correlation between XICODS and EULAR Sjögren’s indices. Open Access Rheumatol. ;11:265–274. Available at: https://www.dovepress.com/correlation-between-xerostomia-index-clinical-oral-dryness-scale-and-e-peer-reviewed-fulltext-article-OARRR\u003c/li\u003e\n\u003cli\u003eDas P et al (2016) Dry mouth and clinical oral dryness scoring systems. Ther Adv Chronic Dis. ;5:192–201. Available at: https://journals.sagepub.com/doi/10.1177/205016841600500110\u003c/li\u003e\n\u003cli\u003eOsailan S (2022) Subjective Score for Oral Dryness (SSOD). Med Sci (Basel). ;26[123]:e2302. Available at: https://discoveryjournals.org/medicalscience/current_issue/v26/n123/ms191e2302.pdf\u003c/li\u003e\n\u003cli\u003eRODI validation. Clin Oral Investig (2019) Available at: https://link.springer.com/article/10.1007/s10266-018-0339-4\u003c/li\u003e\n\u003cli\u003ethe journal. Preparing your manuscript (sections \u0026amp; data availability). Available at: https://bmcoralhealth.biomedcentral.com/submission-guidelines/preparing-your-manuscript\u003c/li\u003e\n\u003cli\u003eBMC (Springer Nature). Editorial policies (ethicscompeting interests). Available at: https://www.biomedcentral.com/getpublished/editorial-policies\u003c/li\u003e\n\u003cli\u003eBMC. Declarations (ethics approvalconsentdata availability). Available at: https://www.biomedcentral.com/about/declarations\u003c/li\u003e\n\u003cli\u003eSpringer Nature. Data Availability Statements—guidance. Available at: https://www.springernature.com/gp/authors/research-data-policy/data-availability-statements\u003c/li\u003e\n\u003cli\u003eUribe SE et al (2022) Data availability \u0026amp; FAIRness in dental research. J Evid Based Dent Pract. ;22[3]:101727. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9516597/\u003c/li\u003e\n\u003cli\u003eWorld Health Organization Bulletin. Khat chewing in Yemen: turning over a new leaf (2008) Available at: https://www.scielosp.org/article/bwho/2008.v86n10/741-742/\u003c/li\u003e\n\u003cli\u003eWedegaertner F et al (2010) Motives for khat use in Yemen. Subst Abuse Treat Prev Policy. ;5:4. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC3006386/\u003c/li\u003e\n\u003cli\u003eThomson WM et al (2000) Further testing of the XI. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. ;89:46–50. Available at: https://pubmed.ncbi.nlm.nih.gov/10633939/\u003c/li\u003e\n\u003cli\u003eAl-Mawarreb AAl-Motarreb A (2010) Khat chewing and cardiovascular disease. Phytomedicine. ;17:1227–1234. Available at: https://pubmed.ncbi.nlm.nih.gov/20621179/\u003c/li\u003e\n\u003cli\u003eEl-Menyar A et al (2015) Khat use: history and heart failure. Oman Med J. ;30:77–82. Available at: https://www.omjournal.org/fultext_PDF.aspx?DetailsID=617\u0026amp;type=fultext\u003c/li\u003e\n\u003cli\u003eEMCDDA/European Union Khat drug profile. Available at: https://www.euda.europa.eu/publications/drug-profiles/khat_en\u003c/li\u003e\n\u003cli\u003eLo Faro AF et al (2020) Khat pharmacology and toxicology: a review. Front Pharmacol. ;11:558925. Available at: https://www.frontiersin.org/articles/10.3389/fphar.2020.558925/full\u003c/li\u003e\n\u003cli\u003eAstatkie A et al (2015) Prevalence of khat chewing in Ethiopian university students. Subst Abuse Treat Prev Policy. ;10:17. Available at: https://doi.org/10.1186/s13011-015-0018-3\u003c/li\u003e\n\u003cli\u003eAbdullah MJ (2015) Prevalence of xerostomia in adults. J Clin Exp Dent. ;7:e45–e53. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC4349822/\u003c/li\u003e\n\u003cli\u003evan der Thomson WMde Baat CIkebe KMatsuda KEnoki KHopcraft MSLing GY (2011) Shortening the xerostomia inventory. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1123:322–327. 10.1016/j.tripleo.2011.03.024\u003c/li\u003e\n\u003cli\u003eClinical trial registration: Not applicable (observational study; not a clinical trial)\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"khat, xerostomia, unstimulated salivary flow, CODS, SXI-D, Yemen","lastPublishedDoi":"10.21203/rs.3.rs-8462830/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8462830/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo evaluate the association between khat chewing and oral dryness among Yemeni adults using clinical (Clinical Oral Dryness Score; CODS), symptom-based xerostomia assessment (Summated Xerostomia Inventory–Dutch Version; SXI-D), and unstimulated salivary flow rate (uSFR) outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this clinic-based cross-sectional comparative study (n = 200), participants were classified as khat chewers (n = 171) or non-chewers (n = 29). CODS (1–10) and xerostomia symptoms (SXI-D; 5–15) were assessed at baseline. Unstimulated saliva was collected by the spitting method over 15 minutes, and uSFR (mL/min) was calculated. Among chewers, uSFR was additionally measured immediately before and after a typical khat session (paired assessment).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMost participants had mild-to-moderate clinical dryness (CODS 1–3: 49.5%; CODS 4–6: 45.5%), with 5.0% classified as severe (CODS 7–10). Mean baseline uSFR was lower in chewers than non-chewers (0.387 vs 0.445 mL/min). Among chewers, mean uSFR decreased from 0.395 mL/min pre-session to 0.229 mL/min post-session (p \u0026lt; 0.001). Xerostomia symptoms were common; 39.5% reported a dry mouth on a single-item screen.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKhat chewing was associated with reduced unstimulated salivary flow and frequent oral dryness in this Yemeni adult cohort, and salivary flow decreased substantially after a typical chewing session.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Relevance: \u003c/strong\u003eOral health providers in khat-prevalent settings should screen for xerostomia and counsel chewers on hydration, caries risk mitigation, and symptom management, especially following prolonged sessions.\u003c/p\u003e","manuscriptTitle":"Khat chewing, xerostomia, and unstimulated salivary flow among Yemeni adults: a cross-sectional comparative study using sialometry, the Clinical Oral Dryness Score (CODS), and the Summated Xerostomia Inventory (SXI-D)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-06 23:49:14","doi":"10.21203/rs.3.rs-8462830/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7dcea1dc-ce91-422f-beb1-15dac1fd91da","owner":[],"postedDate":"January 6th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-16T20:08:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-06 23:49:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8462830","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8462830","identity":"rs-8462830","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}