The Impact of Physical Activity (PA) on the Prevention of Type 2 Diabetes; Evidence and Lessons Learned from the Diabetes Prevention Program (DPP), a Long-Standing Clinical Trial Incorporating Subjective and Objective Activity Measures
<b>Objective:</b> Across the DPP follow-up, cumulative diabetes incidence remained lower in the lifestyle compared to placebo and metformin randomized groups and could not be explained by weight. Collection of self-reported PA (yearly) with cross-sectional objective PA (in follow-up) allowed for examination of PA and its long-term impact on diabetes prevention. <p><b>Research Design and Methods:</b> Yearly self-reported PA and diabetes assessment, OGTT, (fasting glucose semi-annually) was collected for 3232 participants with one accelerometry assessment 11-13 years after randomization (n=1,793). Mixed models determined PA differences across treatment groups. The association between PA and diabetes incidence was examined using Cox proportional hazards models. </p> <p><b>Results:</b> There was a 6% decrease (Cox proportional HR 0.94 [0.92, 0.96]; P< 0.001) in diabetes incidence per 6 MET-hrs/week increase in time-dependent PA for the entire cohort over an average 12 years (controlled for age, sex, baseline PA and weight). The effect of PA was greater (12% decrease) among participants less active at baseline (<7.5 MET-hrs/week) (n=1338; HR 0.88 [0.83, 0.93] P<0.0001) with stronger findings for lifestyle participants. Lifestyle had higher cumulative PA compared with metformin or placebo (p<0.0001) and higher accelerometry total minutes/day measured in follow-up (P=0.001 and 0.047). All associations remained significant with weight in the models.</p> <p><b>Conclusions:</b> PA was inversely related to incident diabetes in the entire cohort across the study with cross-sectional accelerometry results supporting these findings. This highlights the importance of PA within lifestyle intervention efforts designed to prevent diabetes and urge health-care providers to consider both PA and weight when counseling high-risk patients.</p>