LIFE-STYLE INTERVENTION IN OVERWEIGHT INDIVIDUALS WITH A FAMILY HISTORY OF DIABETES

OBJECTIVE- To assess the effect of lifestyle intervention over 2 years on changes in v. fight, coronary heart disease (CHD) risk factors, an d incidence of diabetes in ol overweight individuals with a parental h istory of diabetes. RESEARCH DESIGN AND METHODS- Participants (n = 154 ), who were 30-100% over ideal body weight, had one or both parents wi th diabetes. and were currently nondiabetic, were randomly assigned to 2-year treatments focused on diet (decreasing calories and fat intake ), exercise (goal of 1,500 kcal/week of moderate activity), or the com bination of diet plus exercise or to a no-treatment control group. Sub jects were reassessed at 6 months, 1 year, and 2 years. RESULTS- At 6 months, the groups differed significantly on measures of eating, exerc ise, and fitness; weight losses in the diet and diet-plus-exercise gro ups were significantly greater than in the exercise and control condit ions. Weight losses were associated with positive changes in CHD risk factors. After 6 months, there was gradual deterioration of behavioral and physiological changes, so that at 2 years, almost no between-grou p differences were maintained. Differences between groups in risk of d eveloping diabetes were of borderline significance (P = 0.08). Stronge st predictors were impaired glucose tolerance at baseline, which was p ositively related to risk of developing diabetes, and weight loss from baseline to 2 years, which was negatively related, in all treatment g roups, a modest weight loss of 4.5 kg reduced the risk of type diabete s by similar to 30% compared with no weight loss. CONCLUSIONS- Althoug h initially successful. the interventions studied here were not effect ive in producing long-term changes in behavior, weight, or physiologic al parameters. However n eight loss from 0 to 2 years reduced the risk of developing type 2 diabetes. Since modest weight loss significantly reduced risk of ripe 2 diabetes, further research is needed to determ ine how best to increase the percentage of subjects achieving at if as t a modest weight loss.