Years of life with and without limitation in physical function and in activities of daily living by body mass index among older adults

Background While older adults with pre-obesity and Class I obesity have similar or lower mortality risk versus those with normal weight, a heavier body mass index (BMI) may not translate into more healthy life years. Utilizing longitudinal data on 3452 older (>= 60 years) Singaporeans, we assessed the association between BMI and years of remaining life overall with and without limitation in physical function and in activities of daily living (ADLs). Methods Difficulty in any of nine tasks involving upper or lower extremities was considered as limitation in physical function, and health-related difficulty in any basic ADL or instrumental ADL as limitation in ADLs. We utilized multistate life tables, including BMI as a time-varying covariate. Results At age 60, life expectancy (LE) was similar for those with normal weight, pre-obesity and obesity. However, those with obesity, versus normal weight, had 6.3 [95% confidence interval: 3.4-9.2] more years with limitation in physical function and 4.9 [3.4-6.5] less years without limitation in physical function. Those with pre-obesity, versus normal weight, also had 3.7 [1.9-5.3] more years with limitation in physical function. The same pattern across BMI categories was observed for years of life with and without limitation in ADLs. In stratified analyses, similar associations of BMI with years of life with and without limitation in physical function and in ADLs were observed across gender, ethnicity, and educational status. Conclusions The increasing global prevalence of obesity may result in an increase in years of life with limitation in physical function and in ADLs at older ages. Older adults, their families and healthcare systems should be cognizant of this issue.