Introduction:
Although weight loss has favorable effects on intermediate outcomes, such as blood pressure and insulin resistance, few studies have examined its effects on long-term outcomes including total mortality.
Methods:
In the Trials of Hypertension Prevention (TOHP) individuals aged 30-54 years with high normal BP were randomized to a weight loss intervention, to one of several other lifestyle or dietary supplement interventions, or to usual care. All participants from Phase 1 (1987-90) and Phase 2 (1990-5) were followed for mortality through 2013. The association of weight change during any of the interventions with long-term mortality up to 18-24 years after the trial periods was examined among 3828 participants who fell into a high baseline weight stratum, defined as body mass index at least 26 kg/m2 in men and 24 kg/m2 in women.
Results and Conclusions:
There were 1477 high-weight participants in Phase 1 and 2351 in Phase 2, of whom 21% and 50%, respectively, were assigned to a weight loss intervention. Overall, mean weight change during the trial period was -1.8 lbs (-0.8% of baseline body weight) over 1.5 years in Phase 1 and 1.6 lbs (0.8%) over 3-4 years in Phase 2. A total of 556 (15%) lost > 5%, 1,101 (29%) lost <=5%, 1,567 (41%) gained less than 5%, and 604 (16%) gained > 5% in body weight. Corresponding hazard ratios (HRs) for total mortality were 0.82 (95% confidence interval (CI)=0.57-1.18), 0.94 (95% CI=0.72-1.23), 1.00 (reference), and 1.29 (95% CI=0.92-1.80) (p-trend = 0.046). There was a direct linear relationship with percent change in weight during the trial period and later mortality (HR=1.14 per 5% change, 95% CI=1.02-1.28, p=0.019). This association persisted throughout the course of mortality follow-up (Figure). In these healthy individuals taking part in lifestyle and nutrition supplement trials , short-term weight change was directly associated with mortality about two decades later. These results are consistent with a long-term beneficial effect of presumed intentional weight loss on total mortality.
Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial