Sitting Time and Waist Circumference Are Associated With Glycemia in U.K. South Asians: Data from 1,228 adults screened for the PODOSA trial

OBJECTIVE: To investigate the independent contributions of waist circumference, physical activity, and sedentary behavior on glycemia in South Asians living in Scotland. RESEARCH DESIGN AND METHODS: Participants were 1,228 (523 men and 705 women) adults of Indian or Pakistani origin screened for the Prevention of Type 2 Diabetes and Obesity in South Asians (PODOSA) trial. All undertook an oral glucose tolerance test, had physical activity and sitting time assessed by International Physical Activity Questionnaire, and had waist circumference measured. RESULTS: Mean ± SD age and waist circumference were 49.8 ± 10.1 years and 99.2 ± 10.2 cm, respectively. One hundred ninety-one participants had impaired fasting glycemia or impaired glucose tolerance, and 97 had possible type 2 diabetes. In multivariate regression analysis, age (0.012 mmol ⋅ L(−1) ⋅ year(−1) [95% CI 0.006–0.017]) and waist circumference (0.018 mmol ⋅ L(−1) ⋅ cm(−1) [0.012–0.024]) were significantly independently associated with fasting glucose concentration, and age (0.032 mmol ⋅ L(−1) ⋅ year(−1) [0.016–0.049]), waist (0.057 mmol ⋅ L(−1) ⋅ cm(−1) [0.040–0.074]), and sitting time (0.097 mmol ⋅ L(−1) ⋅ h(−1) ⋅ day(−1) [0.036–0.158]) were significantly independently associated with 2-h glucose concentration. Vigorous activity time had a borderline significant association with 2-h glucose concentration (−0.819 mmol ⋅ L(−1) ⋅ h(−1) ⋅ day(−1) [−1.672 to 0.034]) in the multivariate model. CONCLUSIONS: These data highlight an important relationship between sitting time and 2-h glucose levels in U.K. South Asians, independent of physical activity and waist circumference. Although the data are cross-sectional and thus do not permit firm conclusions about causality to be drawn, the results suggest that further study investigating the effects of sitting time on glycemia and other aspects of metabolic risk in South Asian populations is warranted.