Xerostomia from age 50 to 90 years: prediction and prevalence in cross-sectional and longitudinal studies.

Objectives: To describe longitudinal changes and risk factors for xerostomia in two ageing samples from age 50 to 80 and from 75 to 90.

Material and methods: In 1992 and 2007, postal questionnaires were sent to the total population of 50-year-olds (born 1942, 8,888 individuals) and 75-year-olds (born 1932, 5,195 individuals), respectively. The study was repeated every 5th year up to 2022. The questions encompassed self-reports on sociodemographic domains, and perceived general and oral health. Two questions on xerostomia were included: (i) "Does your mouth feel dry during the day" and (ii) "Does your mouth feel dry at night". The cross-sectional participation rate during the examination years ranged from 74.9% to 54.6% and was 39% in the longitudinal samples.

Results: In the cross-sectional samples the response "yes, often" daytime xerostomia increased from a few percent at age 50 to 9.4% at age 80 and from 8.5% at age 75 to about 15% at age 90. The corresponding figures for reported "yes, often" nighttime xerostomia was from about 5% to 21% from age 50-to-80 and 19% to just above 24% from age 75-to-90. Figures for the longitudinal samples were similar for both conditions and cohorts. Women reported significantly higher prevalences of xerostomia than men at most of the examination points (p < 0.02 to p < 0.001). Nighttime xerostomia reported at baseline at ages 50 and 75 was the most common predictive significant risk factor for having "yes, often" both daytime and nighttime xerostomia at the end point of the study, viz. at ages 80 and 90 (OR 2.5-5.1, p = 0.006 to <0.001).

Conclusions: "Often" xerostomia reported at baseline 30 and 15 year earlier was a common predictor for having xerostomia at ages 80 and 90 in addition to impaired general health, prescribed medication and doctor visits. Clinicians should be aware of the precipitating risk factors for xerostomia that may prevail earlier in life and therefore implement preventive strategies at an early stage.