Dietary glycemic index, glycemic load, and cause-specific mortality: two population-based prospective cohort studies

Background Epidemiological studies on the relationship between dietary glycemic index (GI), glycemic load (GL) and all-cause and cause-specific mortality yielded conflict results. We aimed to assess these associations in Chinese. Methods We conducted this study based on two prospective cohort studies in Shanghai. Dietary information was collected using validated cohort-specific food frequency questionnaires. We used Cox regression model to estimate the hazard ratios (HR) for mortality associated with GI and GL. Results After median follow-up periods of 12.8 years for 59,770 men and 18.2 years for 74,735 women, 8,711 deaths in men and 10,501 deaths in women were documented. After we controlled the potential confounders, dietary GI, GL, and carbohydrate intake were associated with a higher risk of cardiovascular disease (CVD) mortality ( P values for trend = 0.025, 0.001, and 0.001). Dietary GI was associated with lower risk of total and cause-specific mortality in men in the second quartile (Q) (all-cause mortality: HR Q2 vs. Q1 = 0.89, 95%CI: 0.84, 0.95). Dietary GL was associated with lower risk of cancer mortality but higher risk of CVD mortality in men. In women, dietary GI was associated with mortality due to all-cause (HR Max Q4 vs. Q1 = 1.10, 95%CI: 1.04, 1.06), cancer (HR Max Q4 vs. Q1 = 1.12, 95%CI: 1.02, 1.23), and CVD (HR Max Q4 vs. Q1 = 1.10, 95%CI: 1.00, 1.22). Conclusions The present study indicates that diet with higher GI and GL was associated with an increased risk of CVD mortality in Chinese adults. The association may vary for men and women, which need further investigating in other Asian populations.