Underweight/overweight and the risk of long‐term care: Follow‐up study using data of the Japanese long‐term care insurance system

Abstract

Both being underweight and overweight can lead to reduced activity of daily living, which subsequently can require long-term care. The aim of the present study was to clarify the association between underweight/overweight and the subsequent risk of long-term care introduction. We tracked the data of long-term care insurance for 1580 men and women aged ≥65 years who had participated in the official population-based health check-up program in 2001 in Tsunan town and Sekikawa village, Japan. The health check-up data and medical expenditure data for the fiscal year 2001 were used as baseline data. Participants were classified into underweight (body mass index (BMI) <18.5 kg/m(2) ), normal range (BMI = 18.5 to <25.0 kg/m(2) ) and overweight (BMI ≥25.0 kg/m(2) ); the normal range was used as a reference category in Cox proportional hazards models. During the average 5.8 years of follow up, 156 participants were identified to start using long-term care services. Among the young-old elderly (65-74 years-of-age), underweight was significantly associated with the risk of long-term care introduction (multivariable-adjusted HR 4.26, 95% CI 1.69-10.72), whereas overweight was not (multivariable-adjusted HR 1.45, 95% CI 0.69-3.06). Neither underweight nor overweight were significantly associated with long-term care introduction among the old-old elderly (≥75 years-of-age). Underweight could be a good predictor of long-term care introduction in the young-old elderly. We should pay attention to underweight in the elderly, as it might be a manifestation of some physical or mental problems related to future long-term care introduction.