Trajectories of body mass indices and development of frailty: Evidence from the health and retirement study.

OBJECTIVE

To estimate trajectories of body mass index (BMI) and determine their association with incident frailty in later life.

METHODS

Data come from the 2004 to 2012 waves of the Health and Retirement Study, a longitudinal survey of older adults. Analysis was restricted to respondents who were not frail at baseline (n = 10,827). BMI (kg/m(2) ) was calculated from self-reported weight and height. Incident frailty was assessed using the Frailty Index. Longitudinal growth mixture modeling was used to estimate the relationship between BMI trajectories and incident frailty over a 10-year period.

RESULTS

Four trajectory classes were identified: weight gain (n = 162 [1.4%], mean final BMI = 42 kg/m(2) ), weight loss (n = 171 [1.7%], mean final BMI = 25.0 kg/m(2) ), consistent obesity (n = 640 [6.8%], mean final BMI = 34.7 kg/m(2) ), and consistent overweight (n = 9,864 [90.1%] mean final BMI = 26.0 kg/m(2) ). Cumulative incidence of frailty was 19.9%. Relative to the consistent overweight class, the weight gain class had the highest likelihood of incident frailty (odds ratio, OR: 3.61, 95% confidence interval, CI: 2.39-5.46). The consistent obesity (OR: 2.72, 95% CI: 2.06-3.58) and weight loss (OR: 2.81, 95% CI: 1.84-4.30) classes had similarly elevated risk of frailty.

CONCLUSIONS

Weight change and obesity are associated with risk of frailty.