Effect of obesity on falls, injury, and disability.

OBJECTIVES To examine the effect of obesity on the propensity of older adults to fall, sustain a fall-related injury, and develop disability in activities of daily living (ADLs) after a fall. DESIGN Longitudinal population-based survey. SETTING Five waves of the Health and Retirement Study (HRS), 1998-2006. PARTICIPANTS Ten thousand seven hundred fifty-five respondents aged 65 and older in 31,602 person-intervals. MEASUREMENTS Falls within any 2-year interval (9,621 falls). Injuries requiring medical attention (3,130 injuries). Increased ADL disability after a fall within any 2-year interval (2,162 events). Underweight and three classes of obesity (body mass index (BMI) 30.0-34.9 kg/m(2) , Class 1) 35.0-39.9 kg/m(2) , Class 2; ≥40.0 kg/m(2) , Class 3), calculated from self-reported height and weight. Self-reported presence of lower body limitation, pain, dizziness, or vision problems. Self-reported doctor's diagnosis of diabetes mellitus, stroke, or arthritis. RESULTS Compared with normal-weight respondents, the odds ratios (OR) for risk of falling were 1.12 (95% confidence interval (CI) = 1.01-1.24) for obesity Class 1, 1.26 (95% CI = 1.05-1.51) for obesity Class 2, and 1.50 (95% CI = 1.21-1.86) for obesity Class 3. Conditional on falling, only obesity Class 3 was related to a lower propensity for a fall-related injury (OR = 0.62, 95% CI = 0.44-0.87). Obesity Classes 1 and 2 were associated with a higher risk of greater ADL disability after a fall than normal-weight respondents (OR = 1.17, 95% CI = 1.02-1.34; OR = 1.39, 95% CI = 1.10-1.75, respectively). Being underweight was not related to risk of falling or to reported injury or greater ADL limitation after a fall. The presence of measured health problems and chronic conditions was associated with greater risk of falling and, of those who fell, greater ADL limitation but not serious injury. CONCLUSION Obesity appears to be associated with greater risk of falling in older adults, as well as a higher risk of greater ADL disability after a fall. Obesity (BMI ≥ 40 kg/m(2) ) may reduce the risk of injury from a fall. Further investigation of the mechanisms of obesity on falls and related health outcomes is warranted.