Weight-loss attempts and risk of major weight gain: a prospective study inFinnish adults

Background: The effects of weight-loss attempts on long-term weight gain re main unclear. Objective: The objective was to study prospectively how attempts to lose we ight relate to future risk of major weight gain (>10 kg) and whether famili al factors affect this relation. Design: Participants in the Finnish Twin Cohort (3536 men and 4193 women ag ed 18-54 y at baseline) were followed up for 6-15 y. The role of familial f actors was studied in 1705 twin pairs in this cohort who were discordant fo r weight-loss attempts at baseline. Baseline (1975) and follow-up (1981 and 1990) data-including weight, weight-loss attempts (dieting), and selected confounders-were obtained via mailed questionnaires. Results: Average weight gain was at most weakly associated with weight-loss attempts. The risk of major weight gain for subjects attempting to lose we ight at baseline was greatest among initially young (18-29 y) men lover 6 a nd 15 y, respectively-odds ratios: 2.01 and 1.74; 95% CI: 1.13, 3.57 and 1. 11, 2.75) and middle-aged (30-54 y) women lover 6 and 15 y, respectively-2. 43 and 1.52; 1.33, 4.42 and 1.06, 2.22) and persisted after potential confo unders were controlled for. These risks decreased and became nonsignificant in the pairwise twin analysis, suggesting that the relation between dietin g and subsequent major weight gain may also have a familial component. Conclusions: Weight-loss attempts may be associated with subsequent major w eight gain, even when several potential confounders are controlled for. Gen etic and familial factors may contribute to this association.