Intensive Weight Loss Intervention and Cancer Risk in Adults with Type 2 Diabetes: Analysis of the Look AHEAD Randomized Clinical Trial.

OBJECTIVE: This study was designed to determine whether intensive lifestyle intervention (ILI) aimed at weight loss lowers cancer incidence and mortality. METHODS: Data from the Look AHEAD trial were examined to investigate whether participants randomized to ILI designed for weight loss would have reduced overall cancer incidence, obesity-related cancer incidence, and cancer mortality, as compared with the diabetes support and education (DSE) comparison group. This analysis included 4,859 participants without a cancer diagnosis at baseline except for nonmelanoma skin cancer. RESULTS: After a median follow-up of 11 years, 684 participants (332 in ILI and 352 in DSE) were diagnosed with cancer. The incidence rates of obesity-related cancers were 6.1 and 7.3 per 1,000 person-years in ILI and DSE, respectively, with a hazard ratio (HR) of 0.84 (95% CI: 0.68-1.04). There was no significant difference between the two groups in total cancer incidence (HR, 0.93; 95% CI: 0.80-1.08), incidence of nonobesity-related cancers (HR, 1.02; 95% CI: 0.83-1.27), or total cancer mortality (HR, 0.92; 95% CI: 0.68-1.25). CONCLUSIONS: An ILI aimed at weight loss lowered incidence of obesity-related cancers by 16% in adults with overweight or obesity and type 2 diabetes. The study sample size likely lacked power to determine effect sizes of this magnitude and smaller.

The relationship of social support with treatment adherence and weight loss in Latinos with type 2 diabetes.

OBJECTIVE: Little is known about the effects of social support on weight loss in Latinos. This study determined whether sex moderated and treatment adherence mediated the association between social support and weight loss. METHODS: Data from 278 Latino males and females with type 2 diabetes in the Intensive Lifestyle Intervention of the Look AHEAD trial were analyzed. Multivariable modeling tested for moderation and parallel multiple mediator modeling simultaneously tested the mediating effects of adherence to physical activity, diet, and session attendance on the relationship between baseline social support and percent weight loss at 1 year. RESULTS: Social support for physical activity (having family and friends join in physical activity) was related to weight loss. Adherence to physical activity was related to both social support for physical activity and weight loss. Sex did not moderate these relationships. Adherence to physical activity completely mediated the relationship between social support for physical activity and weight loss. CONCLUSIONS: Increasing companionship for physical activity may be an effective intervention strategy to promote behaviors important for weight loss among Latinos.