Incidence of type 2 diabetes in the randomized multiple risk factor intervention trial
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Updated: May 6, 2026
A Zebrafish Model of Diabetes Mellitus and Metabolic Memory
Published on: February 28, 2013
George Davey Smith1, Yiscah Bracha, Kenneth H Svendsen
1Department of Social Medicine, University of Bristol, Bristol, United Kingdom. zetkin@bristol.ac.uk
Background:
Weight loss and increased physical exercise reduce the risk for diabetes in people with impaired glucose tolerance. Randomized trial evidence on the effect of these interventions on people without impaired glucose tolerance is lacking.
Objective:
To examine the influence of a comprehensive intervention program on the risk for developing diabetes in men without impaired glucose tolerance and in a post hoc subgroup analysis by baseline cigarette smoking status.
Design:
Randomized, controlled trial.
Setting:
22 clinical centers for the Multiple Risk Factor Intervention Trial (MRFIT).
Participants:
12,866 men age 35 to 57 years at risk for cardiovascular disease were randomly assigned to either a special intervention or usual care group and followed for 6 to 7 years; this report focuses on 11,827 men without diabetes or impaired glucose tolerance at entry for whom follow-up glucose measurements were available.
Measurements:
Cardiovascular disease risk factors, fasting blood glucose levels, and diabetes medication history were assessed before randomization and annually.
Intervention:
Men in the special intervention group were counseled to change diet (reduce saturated fat, cholesterol, and calorie intake), to stop smoking, and to increase physical activity. Blood pressure was treated more intensively in the special intervention group than in the usual care group.
Results:
11.5% of the special intervention group and 10.8% of the usual care group developed diabetes over 6 years of follow-up (hazard ratio, 1.08 [95% CI, 0.96 to 1.20]). The special intervention-usual care hazard ratio for diabetes was 1.26 (CI, 1.10 to 1.45) among smokers (63%) and 0.82 (CI, 0.68 to 0.98) among nonsmokers (37%). These estimates differed significantly (P = 0.0003). Weight gain after smoking cessation and the use of antihypertensive drugs may have counterbalanced the beneficial effect of the lifestyle intervention for the special intervention group smokers, while the lifestyle intervention was beneficial among nonsmokers.
Limitations:
Principal findings are based on a post hoc subgroup analysis.
Conclusions:
In nonsmokers, an intervention program that included nutrition counseling to produce reductions in weight, serum cholesterol, and (along with antihypertensive medication) blood pressure reduced the risk for diabetes.
Insights
A lifestyle intervention reduced diabetes risk in non-smokers without impaired glucose tolerance. However, the intervention did not significantly impact diabetes risk in smokers, possibly due to weight gain post-cessation.
Area of Science:
- Cardiovascular Disease Prevention
- Metabolic Health
- Clinical Trials
Background:
- Lifestyle interventions like weight loss and exercise are known to reduce diabetes risk in individuals with impaired glucose tolerance.
- Evidence regarding the impact of these interventions on individuals without impaired glucose tolerance is limited.
- This study investigates a comprehensive intervention program's effect on diabetes risk in men without pre-existing glucose intolerance.
Purpose of the Study:
- To assess the efficacy of a comprehensive lifestyle intervention in preventing diabetes development among men without impaired glucose tolerance.
- To conduct a subgroup analysis examining the intervention's effect based on baseline cigarette smoking status.
Main Methods:
- A randomized controlled trial involving 11,827 men without diabetes or impaired glucose tolerance.
- Participants were assigned to either a special intervention group or a usual care group.
- Intervention included dietary counseling, smoking cessation support, increased physical activity, and intensive blood pressure management.
Main Results:
- Over 6 years, 11.5% in the intervention group and 10.8% in the usual care group developed diabetes.
- The intervention significantly reduced diabetes risk in non-smokers (hazard ratio 0.82).
- In smokers, the intervention showed no significant benefit (hazard ratio 1.26), with potential counterbalancing factors like weight gain post-smoking cessation.
Conclusions:
- A comprehensive lifestyle intervention program effectively reduced diabetes risk in non-smoking men without impaired glucose tolerance.
- The intervention's benefits were not observed in smokers, suggesting other factors may influence diabetes development in this group.
- Further research is needed to understand the complex interplay of lifestyle, smoking cessation, and diabetes risk.
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