Long-term obesity and physical functioning in older Americans

Americans are becoming obese earlier in their lives, increasing the average exposure to obesity. Nonetheless, the impact of long-term obesity on later life functioning is not well known.

We analyzed data from 7258 adults aged 60-79 years from the US 1999-2010 National Health and Nutrition Examination Survey. Respondents were defined as limited if they reported 'some difficulty' 'much difficulty' or 'unable to do' any of the eight functional tasks. Respondents were defined as severely limited if they reported 'much difficulty' or 'unable to do' any task. Generalized regression models (logistic and Poisson) predicted the relative odds of any limitation, severe limitation, the total number of limitations and each individual limitation as a function of body mass index (BMI) at age 25 years and current BMI. Models were adjusted for age, sex, race/ethnicity and level of education.

Overall, being overweight or obese at age 25 years was associated with higher odds of being functionally limited, but these associations were greatly diminished or eliminated after adjustment for current BMI. For example, those obese at age 25 years had 2.38 times the odds (95% confidence interval (CI): 1.77, 3.20) of reporting any functional limitations compared with those normal weight at 25 years, but only 1.28 times the odds (95% CI: 0.93, 1.76) after adjustment for current BMI. For severe limitations, the corresponding results were 2.72 (95% CI: 2.13-3.46) and 1.32 (95% CI:1.00-1.75) before and after adjustment for current BMI. Some associations between obesity at age 25 years and individual tasks remained significant after adjustment for current BMI.

We conclude that long-term overweight/obesity are significantly associated with later life functional limitations, though this is largely explained by their strong association with higher levels of later-life BMI. Prevention of additional weight gain for those who are overweight or obese early in life could help mitigate their risk of future loss of functioning.