National prevalence of frailty in the older Japanese population: Findings from a nationally representative survey

Background: Japan has the largest aging population in the world, thus, a focus on frailty is important in clinical geriatric practice. Using a nationally representative sample, this study provided national estimates of the prevalence of frailty among community-dwelling older Japanese people. We also examined variations in the prevalence by sociodemographic characteristics, health conditions, and geographical regions. Methods: Data came from the National Survey of the Japanese Elderly in 2012. The data were collected using a home visit and face-to-face interviews with trained interviewers. The sample consisted of 2206 adults aged >= 65 years. We used the widely accepted definition of physical frailty phenotype and calculated weighted estimates of the prevalence of frailty. Results: Overall estimated prevalence was 8.7 % (7.5 %-9.9 %) for frail, 40.8 % (38.7 %-42.9 %) for prefrail, and 50.5 % (48.4 %-52.6 %) for robust. Frailty was more prevalent in older groups, women, and those with lower socioeconomic status, which was measured by education and household income. Frail people tended to have worse health. We also observed a regional variation: frailty prevalence tended to be higher in eastern than western Japan. Conclusions: This study provides important evidence on the prevalence of frailty in older Japanese people and found substantial disparities by sociodemographic characteristics, health conditions, and geographical regions.