Obesity, physical function, and mortality in older adults

Abstract

Objectives: To estimate the effects of excess body weight on objective and subjective physical function and mortality risks in noninstitutionalized older adults.

Design: Population-based cohort study.

Setting: The English Longitudinal Study of Ageing (ELSA).

Participants: Three thousand seven hundred ninety-three participants in the ELSA aged 65 and older followed up for 5 years.

Measurements: Analyses compared the risks of impaired physical function and mortality for subjects who were at the recommended weight (body mass index (BMI)=20.0-24.9) with those who were overweight (BMI=25.0-29.9), obese (BMI=30.0-34.9) or severely obese (BMI>or=35.0). Outcome measures were difficulties with activities of daily living (ADLs), score on the Short Physical Performance Battery, and mortality.

Results: Participants in higher BMI categories had greater risk of impaired physical function at follow-up but little or no greater risk of mortality. For example, compared with men of recommended weight, obese men (BMI=30.0-34.9) had relative risk ratios of difficulties with ADLs of 1.99 (95% confidence interval (CI)=1.42-2.78), of measured functional impairment of 1.51 (95% CI=1.05-2.16), and of mortality of 0.99 (95% CI=0.60-1.61). Findings were robust when excluding those who lost weight, smoked, or had poor self-rated health.

Conclusion: Excess body weight in people aged 65 and older is associated with greater risk of impaired physical function but not with greater mortality risk. Societies with growing numbers of overweight and obese older people are likely to face increasing burdens of disability-associated health and social care costs.