Background
Trials have demonstrated the efficacy of rigorous diet and physical activity promotion (D&PA) programs for adults at increased risk for type 2 diabetes to reduce diabetes incidence and improve measures of glycemia.
Purpose
To evaluate D&PA programs for individuals at increased risk for type 2 diabetes primarily to lower diabetes risk, lower body weight, and improve glycemia.
Data Sources
MEDLINE, Cochrane Central Register of Controlled Trials, CAB Abstracts, Global Health, and Ovid HealthStar from 1991 through 27 February 2015, with no language restriction.
Study Selection
8 researchers screened articles for single group or comparative studies of combined D&PA programs with at least 2 sessions of at least 3 month duration in participants at increased risk for type 2 diabetes.
Data Extraction
7 researchers extracted data—on study design, participant, intervention, outcome descriptions, and results—and assessed study quality.
Data Synthesis
53 studies (30 D&PA vs. control, 13 more vs. less intensive, 13 in single programs) evaluated 66 programs. Compared with usual care, D&PA reduced type 2 diabetes incidence (RR = 0.59; 95% CI 0.51, 0.66; 16 studies), lowered body weight (net change = −2.2%; 95% CI −2.9, −1.4; 24 studies) and fasting blood glucose (net change = −0.12 mmol/L; 95% CI −0.20, −0.05; 17 studies), and improved other cardiometabolic risk factors. There was limited evidence for clinical events. More intensive programs were more effective.
Limitations
The wide variation in D&PA programs limited identification of features most relevant to effectiveness. Evidence on clinical outcomes and in children was sparse.
Conclusions
Combined D&PA promotion programs are effective to decrease diabetes incidence and improve cardiometabolic risk factors for patients at increased risk. More intensive programs are more effective.
Primary Funding Source
Centers for Disease Control and Prevention Community Preventive Services Task Force.