Accelerometer-Derived Sedentary and Physical Activity Time in Overweight/Obese Adults with Type 2 Diabetes: Cross-Sectional Associations with Cardiometabolic Biomarkers

Objective To examine the associations of sedentary time and physical activity with biomarkers of cardiometabolic health, including the potential collective impact of shifting mean time use from less-to more-active behaviours (cross-sectionally, using isotemporal substitution), in adults with type 2 diabetes. Methods Participants with overweight/obese body mass index (BMI; >= 25 kg/m(2)) (n = 279; 158 men, mean [SD] age = 58.2 [8.6] years) wore Actigraph GT1M accelerometers (waking hours; seven days) to assess moderate-to vigorous-intensity physical activity (MVPA), light-intensity activity, and sedentary time (segregated into non-prolonged [accumulated in bouts <30min] and prolonged [accumulated in bouts >= 30 min]). Cross-sectional associations with waist circumference, BMI, fasting blood (HbA(1c), glucose, triacylglycerols, high-density lipoprotein cholesterol), and blood pressure of these activity variables (30 min/day increments) were examined adjusted for confounders and wear then, if significant, examined using isotemporal substitution modelling. Results Waist circumference and BMI were significantly (p<0.05) associated with more prolonged sedentary time and less light-intensity activity. Light intensity activity was also significantly associated with lower fasting plasma glucose (relative rate: 0.98, 95% CI: 0.97, 1.00; p<0.05). No biomarker was significantly associated with non-prolonged sedentary time or MVPA. Lower mean prolonged sedentary time (-30 min/day) with higher mean light intensity time (+30 min/day) was significantly associated with lower waist circumference (beta = -0.77, 95% CI: -1.33, -0.22 cm). Lower mean prolonged sedentary time (-30 min/day) with either 30 min/day higher mean non-prolonged sedentary time (beta = -0.35, 95% CI: -0.70, -0.01 kg/m(2)) or light-intensity time (beta = -0.36, -0.61, -0.11 kg/m(2)) was associated with significantly lower average BMI. Conclusions Significantly improved mean levels of waist circumference and BMI were observed when shifting time from prolonged sedentary to non-prolonged sedentary or light-intensity activity (cross-sectionally). Lifestyle interventions in overweight/obese adults with type 2 diabetes might consider targeting shifts in these non-MVPA activities to more rigorously evaluate their potential cardiometabolic benefit in this population.