Magnesium intake and risk of type 2 diabetes: meta-analysis of prospective cohort studies.

OBJECTIVE: Emerging epidemiological evidence suggests that higher magnesium intake may reduce diabetes incidence. We aimed to examine the association between magnesium intake and risk of type 2 diabetes by conducting a meta-analysis of prospective cohort studies.

RESEARCH DESIGN AND METHODS: We conducted a PubMed database search through January 2011 to identify prospective cohort studies of magnesium intake and risk of type 2 diabetes. Reference lists of retrieved articles were also reviewed. A random-effects model was used to compute the summary risk estimates.

RESULTS: Meta-analysis of 13 prospective cohort studies involving 536,318 participants and 24,516 cases detected a significant inverse association between magnesium intake and risk of type 2 diabetes (relative risk [RR] 0.78 [95% CI 0.73-0.84]). This association was not substantially modified by geographic region, follow-up length, sex, or family history of type 2 diabetes. A significant inverse association was observed in overweight (BMI ≥25 kg/m(2)) but not in normal-weight individuals (BMI <25 kg/m(2)), although test for interaction was not statistically significant (P(interaction) = 0.13). In the dose-response analysis, the summary RR of type 2 diabetes for every 100 mg/day increment in magnesium intake was 0.86 (95% CI 0.82-0.89). Sensitivity analyses restricted to studies with adjustment for cereal fiber intake yielded similar results. Little evidence of publication bias was observed.

CONCLUSIONS: This meta-analysis provides further evidence supporting that magnesium intake is significantly inversely associated with risk of type 2 diabetes in a dose-response manner.