Stimulated Whole Salivary Flow Is Correlated with Xerostomia Severity and Unstimulated Whole Salivary Flow in Adults with Xerostomia Taking Anticholinergic Medications

Objectives This study primarily investigated whether stimulated whole salivary (SWS) flow is correlated with minor salivary flow (MSF) in adults with xerostomia taking anticholinergic medications, and, secondarily, examined correlations between SWS and unstimulated whole salivary (UWS) flow and xerostomia severity. Design We conducted a cross-sectional study of 85 middle-aged adults (mean age: 57.1 ± 5.2 years, range: 45-64) taking anticholinergic medications. Salivary flow rates for SWS, UWS, and labial MSF were measured, and xerostomia severity was assessed using the Xerostomia Inventory (XI). Based on established cutoff values for SWS and UWS, participants were grouped into categories with or without UWS or SWS hyposalivation, and into a combined SWS and UWS hyposalivation category. Correlation and multivariable regression analyses were conducted to examine associations among SWS, MSF, UWS, XI, and anticholinergic burden, with adjustments made for age, sex, and comorbidities. Results SWS was moderately and significantly correlated with MSF. Lower SWS was also significantly correlated with lower UWS and greater xerostomia severity. Women exhibited significantly lower SWS and MSF flow rates and reported higher XI scores compared with men. Subjects with combined SWS and UWS hyposalivation had the lowest MSF rates, whereas participants without hyposalivation had the highest (p = 0.0002). Conclusions Our findings indicate that SWS flow is associated with xerostomia severity and with UWS flow in adults with xerostomia taking anticholinergic medications. However, SWS and UWS hyposalivation did not always co-occur according to established thresholds, suggesting that measuring both may improve the characterization of salivary dysfunction.