Dairy intake and risk of type 2 diabetes

The effect of total dairy products, milk, and calcium intake on risk of type 2 diabetes (T2D) is uncertain, particularly in the Chinese population.

The present study was based on a prospective cohort of 63,257 Chinese men and women aged 45-74 years during enrollment (1993-1998) in Singapore. Dietary information was obtained using a validated 165-item semi-quantitative food-frequency questionnaire. Information about newly diagnosed T2D was collected by self-report during two follow-up interviews in 1999-2004 and 2006-2010. Cox proportional hazard regression method was used to estimate hazard ratios (HRs) and their 95% confidence intervals (CIs) in 45,411 eligible participants.

Incidence rate (95% CI) of T2D was 10.5 (10.2-10.8) per 1000 person-years. Intake of dairy food was significantly associated with reduced T2D risk; compared with the lowest quartile, HRs (95% CI) for the second, third and fourth quartiles of dairy intake were 0.98 (0.91-1.06), 0.96 (0.89-1.03) and 0.90 (0.83-0.98), respectively, after adjustment for potential confounders at baseline (P-trend = 0.01). Daily drinkers of milk had a significant 12% reduction in T2D risk compared with non-drinkers. While dairy calcium was associated with a decreased risk of T2D (HR comparing extreme quartiles 0.84; 95% CI 0.76-0.93; P-trend = 0.001), no association was found for non-dairy calcium (HR 1.02; 95% CI 0.92-1.14; P-trend = 0.61).

In this large cohort study of Chinese adults, dairy product intake and daily milk consumption was associated with a statistically significant, although modest, decrease in risk of developing T2D, which may be independent of its calcium content.