Association of physical performance and self-rated health with multimorbidity among older adults: Results from a nationwide survey in Japan

Objectives: To examine the association of physical performance measures and self-rated health with multimorbidity among older Japanese adults aged >= 60 years using cross-sectional data from a nationwide longitudinal survey. Methods: Using respondents' self-reported data from the 2012 National Survey of the Japanese Elderly, we analyzed multimorbidity involving nine major chronic diseases (heart disease, arthralgia, hypertension, diabetes, stroke, cataract, cancer, respiratory disease, and low back pain). Respondents who reported having two or more of these diseases were identified as having multimorbidity. Multivariate logistic regression analysis was used to examine if physical performance (grip strength and walking speed) and self-rated health were independently associated with multimorbidity after adjusting for potential confounders (e.g., demographic, physiological, and lifestyle-related variables). Results: The responses of 2525 participants who responded to the survey by themselves (i.e., without proxies) were analyzed (response rate: 57.9%). Among the chronic diseases examined, hypertension had the highest prevalence (44.1%), followed by low back pain (25.7%) and cataract (24.7%). Approximately 44.4% of the respondents had multimorbidity. The regression analysis revealed that multimorbidity was significantly associated with both poor grip strength (P = 0.006) and self-rated health (P < 0.001), but not with walking speed (P = 0.479). Conclusions: Multimorbidity is prevalent in older Japanese adults, and poor grip strength and self-rated health were independently and significantly associated with multimorbidity. Health assessments that include these indicators may provide insight into the health status patterns of older adults with multimorbidity and inform the development of health management strategies.