Effects of Reducing Sedentary Time on Glucose Metabolism in Immigrant Pakistani Men

PURPOSE This study aimed to examine the association between changes in objectively measured overall physical activity (PA) and changes in fasting and postprandial plasma insulin, C-peptide, and glucose concentrations in type 2 diabetes-prone immigrant Pakistani men living in Norway and to examine whether this association is explained by changes in moderate and vigorous PA (MVPA) or changes in sedentary time. METHODS The current study is a secondary cohort analysis on data collected from the Physical Activity and Minority Health study, a randomized controlled trial aimed at increasing the PA level, and not sedentary time per se, in a group of sedentary immigrant Pakistani men (n = 150). For the present analyses, the two groups were merged and a cohort analysis was performed. Overall PA (counts per minute) and its subcomponents, sedentary time and MVPA, were measured with accelerometry. Outcome variables were measured after a 2-h standardized glucose tolerance test. RESULTS Change in overall PA was significantly associated with postprandial log-transformed plasma insulin (β = -0.002; 95% confidence interval (CI), -0.003 to 0.000; P = 0.008), C-peptide (β = -2.7; 95% CI, -4.9 to -0.5; P = 0.01), and glucose concentration (β = -0.006; 95% CI, -0.01 to -0.002; P = 0.002). Change in sedentary time was significantly and beneficially associated with changes in postprandial log-transformed plasma insulin (β = 0.002; 95% CI, 0.001-0.003; P = 0.001), C-peptide (β = 3.7; 95% CI, 1.5-6.0; P = 0.001), and glucose concentration (β = 0.006; 95% CI, 0.002-0.1; P = 0.002), independent of changes in MVPA, waist circumference, and other confounders. CONCLUSIONS Increasing overall PA by reducing sedentary time seems as important as increasing time spent at MVPA in relation to postprandial plasma insulin and glucose levels in diabetes-prone immigrant men.