Introduction:
The Look AHEAD trial examined cardiovascular disease incidence in adults with type 2 diabetes randomly assigned to an intensive lifestyle intervention compared to those randomly assigned to diabetes support and education (control). In a substudy, physical activity was assessed using accelerometry, which provides an opportunity to examine whether the incidence of cardiovascular disease varied by the measured change in physical activity.
Hypothesis:
There is a beneficial association between the 1- and 4-year change in physical activity and the pre-specified primary and secondary outcomes in participants in the Look AHEAD trial.
Methods:
Adults (N=1,978; 59.1±6.8 kg; 102.8±19.0 kg) with type 2 diabetes at 8 study sites, who completed physical activity was assessment using accelerometry for 1 week at 0, 1, and 4 years. MET-minutes per week of moderate-to-vigorous physical activity (MVPA) performed in bouts of at least 10 minutes was identified from the accelerometry data. The 1- and 4-year change in MVPA was computed as the difference from baseline. The primary outcome was pre-defined as non-fatal myocardial infarction, stroke, hospitalized angina, and cardiovascular disease death. The first secondary outcome was pre-defined as non-fatal myocardial infarction, stroke, hospitalized angina, CABG/PTCA, hospitalized congestive heart failure, carotid endarterectomy, peripheral vascular disease, and total mortality. The relationships between 1- and 4-year change in physical activity and the primary and secondary outcomes were examined using Cox proportional hazards models with data collapses across the two treatment groups. Hazard ratios (HR) were adjusted for age, sex, history of cardiovascular disease, duration of diabetes, diabetes medication use, baseline weight, change in weight, and baseline physical activity.
Results:
MVPA [Median (25
th
, 75
th
percentile)] was 167.6 (0,545.5), 205.4 (0, 700.2), and 91.3 (0, 418.9) MET-minutes per week at 0, 1 and 4 years, respectively. Change in MVPA at 1-year was not significantly associated with the primary outcome [HR per 100 MET-minutes per week = 1.001 (95% CI: 0.985, 1.017)] or secondary outcome [HR per 100 MET-minutes per week = 0.989 (95% CI: 0.966, 1.013)] assessed across 8.8±2.4 years of follow-up. Change in MVPA at 4-years was significantly associated with a reduction in the primary [HR per 100 MET-minutes per week = 0.949 (95% CI: 0.912, 0.987)] and the secondary outcome [HR per 100 MET-minutes per week = 0.897 (95% CI: 0.843, 0.954)] assessed across 9.2±1.8 years of follow-up.
Conclusions:
Change in physical activity at 4-years is associated with a reduction in incidence of cardiovascular disease in adults with type 2 diabetes. These findings suggest improvements in physical activity may need to be sustained for a relatively long period (4 years) to elicit a beneficial effect on incidence of cardiovascular disease.
Association Between Change in Accelerometer-Measured and Self-Reported Physical Activity and Cardiovascular Disease in the Look AHEAD Trial