Association Between Depressive Tendencies and Bathing or Hot Spring Bathing Habits Among Community-Dwelling Middle-Aged and Older Adults.

Background: This study aimed to examine the association between depressive tendencies and bathing or hot spring bathing habits in community-dwelling individuals aged ≥ 40 years.

Methods: This cross-sectional study included 542 participants from the Tarumizu Study 2021, in which the participants underwent health checks. The frequencies of bathing and hot spring bathing were assessed using a questionnaire. The frequency of bathing was classified into '< 7 times/week' and '7 times/week', whereas the frequency of hot spring bathing was classified into '< 1 time/week' and '≥ 1 time/week'. Depressive tendencies were assessed using the 15-item Geriatric Depression Scale, with a score of ≥ 5 considered depressive tendencies.

Results: Among the participants, 487 (89.9%) bathed 7 times/week, and 124 (22.9%) bathed in hot springs ≥ 1 time/week. The depressive tendency group included 95 (17.5%) participants. The proportion of participants who bathed in hot springs ≥ 1 time/week was significantly lower in the depressive tendency group (14.7%) than in the normal group (24.6%) (p = 0.038). Multivariable logistic regression analysis adjusted for age, sex, income-generating job, outing frequency, mobility problems, smoking history and alcohol intake demonstrated that the odds ratio for depressive tendency was significantly lower for hot spring bathing ≥ 1 time/week than for < 1 time/week (adjusted odds ratio: 0.51, 95% confidence interval: 0.27-0.95, p = 0.033). In contrast, no association was observed between depressive tendencies and bathing frequency.

Conclusions: Hot spring bathing frequency of ≥ 1 time/week was significantly associated with depressive tendencies in community-dwelling middle-aged and older adults. However, depressive tendencies were not associated with bathing frequency. Further longitudinal studies are needed to examine the preventive effects of hot spring bathing on depressive tendencies.