Objective Polypharmacy in elderly individuals may cause reduced flow of saliva and xerostomia. A dry mouth can lead to poor oral function; however, there are no reports on the relationship between polypharmacy and subjective or objective oral dysfunction. The purpose of this study was to clarify the relationship between the number of prescribed medications and subjective and objective oral dysfunction.Methods The subjects of this study were 215 community-dwelling, elderly individuals, aged 75 years or older, who visited the dental clinic in the Chubu region for a dental health examination from January to February 2019. A medical interview was conducted to assess three items that were related to subjective oral function and record four measurements related to objective oral function. In addition, information was collected on the diseases being treated and prescribed medications. A subject with a decrease in any of the three subjective oral function categories was considered to have subjective oral dysfunction. Objective oral dysfunction was analyzed with respect to two types of oral dysfunction: a decrease in all four objective oral functions and a decrease in two or more of the four objective oral functions. Logistic regression analysis was performed to examine the relationship between subjective and objective oral dysfunction after adjustment for sex, age group, inveterate disease, and the number of prescribed medications.Results Individuals who had eight or more prescribed medications had lower subjective oral function than those with seven or fewer medications (odds ratio, 95% confidence interval: 2.3, 1.0-5.1; P<0.05). Individuals with eight or more medications had lower scores in all four objective oral functions than those with seven or fewer medications (4.4 : 1.5-12.6, P<0.01). A decrease in two or more of the four objective oral functions was related to 10 or more prescribed medications (4.3 : 1.2-16.2, P<0.05). In addition, taking eight or more prescribed medications was associated with a decrease in either subjective oral function or all four objective oral functions (8.1 : 2.1-30.8, P<0.01). A decrease in either subjective oral function or two or more objective oral functions was related to taking 10 or more prescribed medications (4.9 : 1.6-15.6, P<0.01).Conclusion In conclusion, more than eight prescribed pharmaceutical medications in the elderly is associated with subjective or objective oral dysfunction.
Keywords: objective oral function; polypharmacy; salivary flow; subjective oral function; xerostomia.