Abstract
BACKGROUND: Obesity may have a protective effect (greater survival) in older adults, a finding known as the "obesity paradox." This study examined the association between self-reported body mass index (BMI) and active life expectancy (ALE) among older U.S. adults. METHODS: Using the Medicare Health Outcomes Survey Cohort 15 (2012 baseline, 2014 follow-up), we estimated life expectancy and ALE by participants' baseline BMI and age using multi-state models. A participant was classified as in an active state if this person reported having no difficulty for any of these six activities of daily living (ADLs). RESULTS: Small differences in life expectancy were noted among persons in normal weight (BMI 18.5-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)), and obesity ranges (BMI 30 kg/m(2) and higher). However, persons with obesity had a significantly lower ALE. ALE at age 65 was 11.1 (11.0-11.2) years for persons with obesity, 1.2 (1.1-1.3) years less than that for the normal weight and overweight persons (12.3 years for both, 12.2-12.4). Persons with class III obesity had a significantly lower life expectancy and ALE than normal weight persons. Although persons with class I or II obesity had a similar life expectancy as normal weight persons, they have a shorter ALE. CONCLUSIONS: Although older adults with obesity have a similar life expectancy as normal weight persons, they have a significantly shorter ALE. Given the complex relationship of BMI and ALE, a "one size fits all" approach to weight management is not advisable.