WEIGHT CHANGE IN OLDER ADULTS: THE ASSOCIATIONS BETWEEN WEIGHT LOSS INTENTION AND BODY COMPOSITION, CVD, CVD RISK FACTORS, AND MORTALITY IN ADULTS 70 YEARS AND OLDER.

Background: Weight loss is a common recommendation for those with overweight and obesity to reduce their risk of developing chronic diseases. Studies of the impact of weight loss on mortality and CVD risk have shown benefits and harm. These conflicting findings may be due to a lack of differentiation between intentional and unintentional weight loss. Older adults are more likely to unintentionally lose weight than younger adults, but few studies have examined the possible differential effects of weight loss intentionality in this population. Methods: We used longitudinal data from the Health, Aging and Body Composition (Health ABC) Study, a cohort of community-dwelling black and Medicare-eligible white men and women aged 70 to 79 years. For aim 1 we examined the associations between annual weight loss intention and 1) 1-year changes in body composition and 2) 1- or 2- year changes in CVD risk factors. Two timeframes were examined: 1) the exposures and outcomes assessed over the same 1-year interval (called simultaneous changes), and 2) exposures and outcomes assessed over two sequential and non-overlapping 1- or 2-year intervals (called lagged changes). For aim 2 we assessed the associations between annual weight loss by weight change group and the 10-year hazard of 1) all-cause mortality and 2) fatal and non-fatal CVD. Results: In the analyses for the simultaneous changes, unintentional weight loss (UWL) and intentional weight loss (IWL), compared to weight maintenance, were strongly associated with reductions in BMI, fat mass index (FMI) and muscle mass index (MMI). Changes in BMI and FMI were larger for IWL than UWL (BMI -1.55, 95% CI: -1.65, -1.46 and -1.35, 95% CI: -1.40, -1.30; FMI -1.39, 95% CI: -1.50, -1.28 and -1.13, 95% CI: -1.18, -1.08). There were no significant differences between the effects of IWL and UWL on the CVD risk factors and body composition measurements. In the overall sample, for every 5 pounds of weight loss, the risk of death increased by 5% (HR: 1.05 95% CI, 1.00 – 1.11;) and the risk of fatal and non-fatal CVD increased by 9% (HR: 1.09, 95% CI, 1.02 – 1.16). In the analyses by weight loss intention, for every 5 pounds of weight loss, the risk of death increased by 21% (HR: 1.21, 95% CI, 1.04 – 1.39) in the UWL group and decreased by 51% (HR: 0.49, 95% CI, 0.26 – 0.93) in the IWL group and the risk of fatal and nonfatal CVD increased by 10% and 6% in the UWL (HR: 1.10, 95% CI 0.90-1.36) group and the IWL (HR: 1.06, 95% CI 0.79- 1.43) group but both 95% confidence intervals included the null value. Conclusion: UWL in older adults is more harmful than all other weight change groups. There were no differences in the associations between IWL and UWL on change in body composition and CVD risk factors but UWL increased the risk of all-cause mortality and fatal and non-fatal CVD events when compared to IWL.