Two-Year Weight Loss but Not Body Mass Index Predicts Mortality and Disability in an Older Japanese Community-Dwelling Population

Abstract

ObjectivePrevious studies in older populations have shown a cardioprotective effect for obesity, an observation known as the obesity paradox. However, whether a decrease or increase in body weight over a certain period affects disability and mortality in older adults remains unknown. Hence, we examined whether the percent body weight change can predict the risk of mortality and disability in older Japanese adults. DesignWe performed a longitudinal prospective cohort study. Setting and participantsWe investigated 1229 community-dwelling older adults (aged ≥65 years) living in Japan. MethodsParticipants were divided into 3 groups (weight loss, stable weight, and weight gain) based on percentage body weight change (using 1 standard deviation from the mean as cutoff points) between 2011 and 2013. Death and disability incidences were monitored between April 2013 and March 2016. Disability was defined as the need for new long-term care insurance (LTCI). ResultsThe rates of death and new LTCI requests over the 3-year follow-up were 2.4% and 4.7%, respectively. The weight loss group (reduction >4.8%) had a 5.0% death rate and an 11.1% new LTCI rate, which were significantly higher than those in the stable weight (1.6% and 3.8%, respectively) and weight gain (ie, gain >3.1%) groups (3.9% and 4.7%, respectively). Cox regression analysis confirmed a higher risk for death [hazard ratio (HR) = 3.10, 95% confidence interval (CI) = 1.31-7.31] and new LTCI requests (HR = 3.03, 95% CI = 1.69-5.43) only in the weight loss group. The body mass index did not significantly influence the risk of death or disability. Conclusions/ImplicationsWeight loss over 2 years but not body mass index was associated with a higher death and disability risk during the subsequent 3-year follow-up period among older participants. Weight change surveillance can improve the quality of health care by early identifying frailty and death risk population.