Association of salivary function with oral health-related quality of life in patients with type 2 diabetes and xerostomia: cross-sectional study

Xerostomia and alterations in salivary function are frequently reported in individuals with type 2 diabetes mellitus (T2DM) and may be associated with oral health-related quality of life (OHRQoL). This study evaluated the associations of xerostomia and salivary parameters with OHRQoL in adults with xerostomia and T2DM. This cross-sectional study included 60 adults with T2DM, HbA1c > 6%, and mild or moderate subjective xerostomia according to CTCAE v3.0. Xerostomia severity was subsequently assessed using the Xerostomia Inventory (XI). Unstimulated whole salivary flow (UWS), stimulated whole salivary Materials and Methodsflow (SWS), salivary pH, total protein concentration, and taste perception were assessed after enrolment. OHRQoL was assessed using OHIP-14. Associations were examined using Spearman rank correlation and multiple linear regression. HIP-14 was strongly inversely correlated with UWS (ρ = −0.874, p < 0.001), SWS (ρ = −0.857, p < 0.001), and total salivary protein (ρ = −0.721, p < 0.001), whereas XI, salivary pH, and composite taste score were not significantly correlated with OHIP-14. In the six-variable regression model, UWS (β = −0.490, p < 0.001) and SWS (β = −0.385, p < 0.001) remained significantly associated with OHIP-14. The model explained 85.4% of the variance (adjusted R² = 0.838).Lower UWS and SWS were associated with poorer OHRQoL after accounting for the other variables included in the multivariable model. These findings indicate an association between reduced salivary flow and poorer oral health-related quality of life among adults with T2DM and xerostomia; causality cannot be inferred from the cross-sectional design.