The association between weight fluctuation and mortality: results from a population-based cohort study.

Previous studies evaluating the association between weight fluctuation and mortality are limited and have conflicting results. This study will further evaluate the association between weight fluctuation and mortality in a nationally representative cohort by performing survival analysis of NHANES I and NHANES I Epidemiologic Follow-up Study (n = 8479; weighted sample = 68,200,905). This cohort was followed from 1971 to 1992 and categorized using weight change over five time points into stable non-obese, stable obese, weight gain, weight loss and weight fluctuation groups. All-cause mortality (ACM) and cardiovascular mortality (CM) were evaluated. Respondents with weight fluctuation had higher ACM (HR: 1.83, 95% CI: 1.25-2.69) and CM hazards ratios (HR: 1.86, 95% CI: 1.10-3.15) than the stable non-obese group, even after controlling for pre-existing disease, initial BMI and excluding those in poor health or incapacitated. Increased mortality was also seen in the weight loss group (ACM HR: 3.36, 95% CI: 2.47-4.55), (CM HR 4.22, 95% CI: 2.60-6.84). The stable obese group did not have increased ACM, but did have increased CM prior to the exclusion of those in poor health or incapacitated. (HR: 2.17, 95% CI: 1.10-4.28). Weight fluctuation is associated with a higher risk of all-cause and cardiovascular disease mortality in the US population, even after adjustment for pre-existing disease, initial BMI and the exclusion of those in poor health or incapacitated. Thus, health care providers should promote a commitment to maintaining weight loss to avoid weight fluctuation and consider patients' weight histories when assessing their risk status.