Age-related changes in elastic properties and moisture content of lower labial mucosa

The purpose of this study was to clarify age-related changes in the elastic properties and moisture content of the lower labial mucosa. Elastic properties and moisture content were also compared between the lower labial mucosa and skin. A total of 85 adults aged 20-82 took part in the study. Elastic properties (distensibility and elasticity) and moisture content of lower labial mucosa and skin were determined in each participant. Measurements for the oral mucosa were taken at the midline of the lower labial mucosa; for the skin, they were taken at the midpoint of the right anterior surface of the forearm. Pearson's correlation coefficient and the Mann-Whitney U test were used for the statistical analysis. A stepwise multiple linear regression analysis was also performed, with age as the dependent variable and sex, distensibility, elasticity and moisture content of the lower labial mucosa as independent variables. A negative correlation was found between age and distensibility of the lower labial mucosa. No correlation was observed between age and elasticity of the lower labial mucosa. A negative correlation was observed between age and moisture content of the lower labial mucosa. A significant difference was observed in moisture content between the 20- to 39-year-old group and the over 40-year-old group. Stepwise analysis identified distensibility and moisture content of the lower labial mucosa as predictive factors of age. The results indicate that distensibility and moisture content of the lower labial mucosa decrease with age. Moisture content in the over 40-year-old group, in particular, was lower than in the 20- to -30-year-old group.