Change in Sedentary Time, Physical Activity, Bodyweight, and Hba1c in High-Risk Adults

PURPOSE: In recent years, there has been a migration towards the use of glycated hemoglobin (HbA1c) in determining glycemic control. This study aimed to quantify the associations between changes in body weight, sedentary time and moderate to vigorous physical activity (MVPA) time with HbA1c levels over a three year period among adults at high risk of type 2 diabetes. METHODS: This study reports baseline and three year follow-up data from the Walking Away from Type 2 Diabetes study. ActiGraph GT3X accelerometers captured sedentary time and MVPA. Linear regression examined the independent associations of changes in sedentary time, MVPA and body weight with HbA1c between baseline and three year follow-up. RESULTS: The sample comprised of 489 participants (mean age 64.2 ± 7.3 years, BMI 31.7 ± 5.1, 63.4% male) with valid baseline and follow-up accelerometer, body weight and HbA1c data. Following adjustment for known confounders, an increase in MVPA time (per 30mins/day) was associated with a decrease in HbA1c percentage(β = -0.11 (-0.18,-0.05), p=0.001) and an increase in body weight (per 6 kg) was associated with an increase in HbA1c percentage (β = 0.08 (0.04,0.12), p<0.001). Presence of dysglycemia at baseline (HbA1c ≥6.0%) strengthened these associations (p<0.001 for interactions). Change in sedentary time was not significantly associated with change in HbA1c after adjustment for change in MVPA time. CONCLUSION: Increases in MVPA and body weight were associated with a reduction and increase in HbA1c respectively, particularly in those with dysglycemia. Quantifying the impact that health behavior changes have on HbA1c can be used to inform prevention programs.