Group-based lifestyle intervention reduced risk of type 2 diabetes

Participants in the Norfolk Diabetes Prevention Study who underwent multiple educational group sessions that included 50-minute sessions of supervised physical activity had significantly lower odds of type 2 diabetes during a mean follow-up of two years compared to those who received usual care.

A group-based lifestyle intervention may help reduce the risk of type 2 diabetes in the primary care setting, a randomized trial found.

In the Norfolk Diabetes Prevention Study, researchers randomized participants to one of three intervention arms: a control arm receiving usual care, a theory-based lifestyle intervention arm of six core and up to 15 maintenance sessions, or the same intervention with support from diabetes prevention mentors (i.e., trained volunteers with type 2 diabetes). The core intervention included two-hour educational group sessions of varying content, and maintenance sessions were discussion based and followed the same format, including a 50-minute supervised physical activity/muscle-strengthening exercise session. Sessions contained no more than 15 participants. The trial had up to 46 months of follow-up from August 2011 to January 2019 at 135 primary care practices and eight intervention sites in the East of England.

The researchers identified 141,973 people at increased risk for type 2 diabetes, screened 12,778 (9%), and randomized those found to be high risk: elevation in fasting plasma glucose level alone (≥110 to <126 mg/dL [≥6.1 to <7.0 mmol/L]) or HbA1c level (≥6.0% to <6.5%; nondiabetic hyperglycemia) plus elevated fasting plasma glucose level (≥100 to <110 mg/dL [≥5.5 to <6.1 mmol/L]). The primary outcome was the development of type 2 diabetes. Results were published online on Nov. 2 by JAMA Internal Medicine.

A total of 1,028 participants were randomized (178 to control, 424 to intervention, and 426 to intervention with mentor support) from Jan. 1, 2011, through Feb. 24, 2017. Mean age was 65.3 years, mean body mass index was 31.2 kg/m2, and mean follow-up was 24.7 months. Overall, 156 participants progressed to type 2 diabetes: 39 of 171 (22.8%) in the control group, 55 of 403 (13.7%) in the intervention group, and 62 of 414 (15.0%) in the intervention with support group. While there was no significant difference between the intervention arms for the primary outcome (odds ratio [OR], 1.14 [95% CI, 0.77 to 1.70]; P=0.51), participants in each intervention arm had significantly lower odds of type 2 diabetes compared to those in the control group (ORs, 0.54 [95% CI, 0.34 to 0.85] [P=0.01] for the intervention group; 0.61 [95% CI, 0.39 to 0.96] [P=0.33] for the intervention with support group; and 0.57 [95% CI, 0.38 to 0.87] [P=0.01] for combined). The effect size was similar in all glycemic, age, and social deprivation subgroups. Mean intervention costs per participant were estimated as $153 in the intervention arm and $301 in the intervention with support arm.

Limitations of the study include that most participants were White and older; therefore, the results may not be generalizable to more ethnically diverse populations or to adolescent and young adults, the authors noted. They concluded, “Our intervention materials and model are translatable and available to clinicians in practice, and suggest that a pragmatic group-based lifestyle intervention reduces the risk of type 2 diabetes in these large populations currently being detected in primary care.”