Differences in the Prevalence of and Factors Associated with Frailty in Five Japanese Residential Areas

Abstract

This study aimed to examine area differences in the prevalence of and factors associated with frailty. This cross-sectional study included metropolitan (eastern and western areas), suburban (districts A and B), and rural areas of Japan (n = 9182, woman 50.9%). Frailty was defined by using a standardized questionnaire comprising three subcategories (fall, nutritional status, and social activities). The prevalence of frailty in the five areas was 14.2% to 30.6% for men and 11.5% to 21.4% for women. The areas with a high frailty prevalence had a significantly lower nutritional status or social activity, or both. Compared to the western metropolitan area, among men, the multivariable-adjusted prevalence ratio (APR) of frailty was significantly higher in the eastern metropolitan area and lower in suburban district A, and among women, the eastern metropolitan and rural areas had significantly higher APRs. Area-stratified multiple Poisson regression analysis showed that age, bone and joint disease, and a subjective economic status were associated with frailty in most areas and that some factors were area-specific, i.e., living alone (for men living in metropolitan areas) and underweight (for women living in suburban areas). The frailty prevalence differed by area, even after multivariable adjustment. Area-specific characteristics and factors associated with frailty may result in area differences.