Associations of Daily Steps and Step Intensity With Incident Diabetes in a Prospective Cohort Study of Older Women: The OPACH Study
Research Design and Methods: Women without physician-diagnosed diabetes (n=4,838; mean age=78.9, sd=6.7) were followed up to 6.9 years; 395 developed diabetes. Hip-worn ActiGraph GT3X+ accelerometers worn for one week enabled measures of total, light intensity, and moderate-to-vigorous (MV) intensity steps/day. Cox proportional hazards analysis modeled adjusted change in the hazard rate for incident diabetes associated with total, light, and MV steps/day. We further estimated the proportion of the steps-diabetes association mediated by body mass index (BMI).
Results: On average, participants took 3,729 steps/day (sd=2,114), of which 1,875±791 were light-intensity steps and 1,854±1,762 were MV-intensity. Greater steps/day were associated with a lower hazard rate for incident diabetes. Confounder-adjusted models for a 2000-steps/day increment yielded hazard ratio (HR) (95%CI)=0.88 (0.78-1.00, p=0.046). After further adjustment for BMI, HR=0.90 (95%CI: 0.80-1.02; p=0.11). BMI did not significantly mediate the steps-diabetes association (proportion mediated = 17.7%, 95% CI=-55.0%-142.0%; p=0.09). The relationship between MV steps/day (HR=0.86; 95%CI=0.74-1.00, p=0.04) and incident diabetes was stronger than for light steps/day (HR=0.97; 95%CI=0.73-1.29; p=0.84).
Conclusion: These findings suggest that for older adults, more steps/day are associated with lower incident diabetes and MV-intensity steps are most strongly associated with a lower hazard of diabetes. This evidence supports that regular stepping is an important risk factor for T2D prevention in older adults.