Association between risk perception, subjective knowledge, and depression in community-dwelling elderly people in Japan

• Risk perception is one of the core factors in theories of health behavior promotion.
• The association between knowledge, risk perception, and depressed mood is unknown.
• Subjective knowledge was weakly positively associated with risk perception and negatively related to depressive mood in a dose–response pattern.
• Risk perception was not significantly associated with depressive mood.
• Subjective knowledge may have protective effect against depression even if it is associated with increased risk perception.

Risk perception is one of the core factors in theories of health behavior promotion. However, the association between knowledge, risk perception, and depressed mood in depression is unknown. The aim of this study was to clarify the relationships between subjective knowledge, risk perception, and objective scores of depression in community-dwelling elderly people in Japan. A total of 747 elderly participants (mean age: 76.1, female: 59.8%) who completed the 15-item Geriatric Depression Scale (GDS-15) along with items assessing subjective knowledge and risk perception were included in the analysis. We assessed the correlation between subjective knowledge and risk perception, and then compare GDS-15 scores by level of subjective knowledge and risk perception. Subjective knowledge was weakly associated with risk perception and related to lower GDS-15 scores in a dose–response pattern, which did not change after adjusting for age, gender, basic activities of daily living (ADL), instrumental ADL, years of education and history of depression. There was no significant association between risk perception and GDS-15 scores. The relationship between knowledge, risk perception, and depressed mood in younger generations is unclear, but warrants examination.