Dietary carbohydrates, glycaemic load, food groups and newly detected type 2 diabetes among urban Asian Indian population in Chennai, India (Chennai Urban Rural Epidemiology Study 59)

Abstract

The aim of the study was to examine the association of dietary carbohydrates and glycaemic load with the risk of type 2 diabetes among an urban adult Asian Indian population. Adult subjects aged >20 years (n 1843) were randomly selected from the Chennai Urban Rural Epidemiology Study, in Chennai city in southern India. Dietary carbohydrates, glycaemic load and food groups were assessed using FFQ. Oral glucose tolerance tests were performed using 75 g glucose in all subjects. Diagnosis of diabetes was based on WHO Consulting Group criteria. OR for newly detected diabetes were calculated for carbohydrates, glycaemic load and specific food groups comparing subjects in the highest with those in the lowest quartiles, after adjustment for potential confounders such as age, sex, BMI, family history of diabetes, physical activity, current smoking, alcohol consumption and relevant dietary factors. We identified 156 (8·5 %) newly diagnosed cases of type 2 diabetes. Refined grain intake was positively associated with the risk of type 2 diabetes (OR 5·31 (95 % CI 2·98, 9·45); P < 0·001). In the multivariate model, after adjustment for potential confounders, total carbohydrate (OR 4·98 (95 % CI 2·69, 9·19), P < 0·001), glycaemic load (OR 4·25 (95 % CI 2·33, 7·77); P < 0·001) and glycaemic index (OR 2·51 (95 % CI 1·42, 4·43); P = 0·006) were associated with type 2 diabetes. Dietary fibre intake was inversely associated with diabetes (OR 0·31 (95 % CI 0·15, 0·62); P < 0·001). In urban south Indians, total dietary carbohydrate and glycaemic load are associated with increased, and dietary fibre with decreased, risk of type 2 diabetes.