Objective: We aimed to investigate the influence of positive family history (FH+) of diabetes and 19 known genetic risk loci on the effectiveness of lifestyle changes and their predictive value on the incidence of type 2 diabetes in the Finnish Diabetes Prevention Study (DPS).
Research design and methods: A total of 522 subjects with impaired glucose tolerance (IGT) were randomized into the control (n = 257) and intervention (n = 265) groups. The mean follow-up was 6.2 years (median 7 years), and the lifestyle intervention, aimed at weight reduction, healthy diet, and increased physical activity, lasted for 4 years (range 1-6 years). An oral glucose tolerance test (OGTT) and assessment of basic clinical variables were performed annually.
Results: The effect of intervention on the incidence of diabetes was almost similar in subjects with FH+ compared with subjects with a negative family history (FH-) of diabetes during the entire follow-up. In the Cox model, including FH, genetic risk SNPs, and randomization group, and adjusted for the effects of age, sex, BMI, and study center, only lifestyle intervention had a significant effect (hazard ratio 0.55, 95% CI 0.41-0.75, P < 0.001) on the incidence of diabetes. Further analyses showed that in addition to the baseline glucose and insulin values, 1-year changes in 2-h glucose and 2-h insulin achieved by lifestyle intervention had a significant effect on the incidence of diabetes.
Conclusions: These results emphasize the effectiveness of lifestyle intervention in reducing the risk of diabetes in high-risk individuals independently of genetic or familial risk of type 2 diabetes.
Trial registration: ClinicalTrials.gov NCT00518167.