Magnesium intake and type II diabetes in Japanese men and women: the Japan Public Health Center-based Prospective Study.

This study examined the association between magnesium intake and type II diabetes risk among Japanese adults. Participants were 25 872 men and 33 919 women aged 45-75 years who had no history of diabetes. Magnesium intake was ascertained using a 147-item food frequency questionnaire. Odds ratio of self-reported physician-diagnosed type II diabetes over 5 years was estimated using logistic regression analysis. A total of 1114 new cases of type II diabetes were self-reported. Magnesium intake was not significantly associated with type II diabetes in either men or women. The multivariable-adjusted odds ratios (95% confidence intervals) of type II diabetes for the highest versus lowest quintile of magnesium intake were 0.86 (0.63-1.16) and 0.92 (0.66-1.28) for men and women, respectively. Although a small effect cannot be excluded in men, magnesium intake may not be appreciably associated with risk of type II diabetes for Japanese adults.

Calcium, vitamin D and dairy intake in relation to type 2 diabetes risk in a Japanese cohort.

AIMS/HYPOTHESIS: Calcium and vitamin D have been implicated in the development of type 2 diabetes, but epidemiological evidence is limited. We examined prospectively the relation of calcium and vitamin D intake to type 2 diabetes risk in a Japanese cohort. METHODS: Participants were 59,796 middle-aged and older men and women, who participated in the Japan Public Health Center-based Prospective Study and had no history of type 2 diabetes or other serious diseases. Dietary intake of calcium and vitamin D were estimated using a validated food frequency questionnaire. Logistic regression was used to assess the association between intake of these nutrients and self-reported newly diagnosed type 2 diabetes. RESULTS: During a 5 year follow-up, 1,114 cases of type 2 diabetes were documented. Overall, calcium intake was not associated with a significantly lower risk of type 2 diabetes; the multivariable odds ratio for the highest vs lowest quartiles was 0.93 (95% CI 0.71-1.22) in men and 0.76 (95% CI 0.56-1.03) in women. However, among participants with a higher vitamin D intake, calcium intake was inversely associated with diabetes risk; the odds ratio for the highest vs lowest intake categories was 0.62 (95% CI 0.41-0.94) in men and 0.59 (95% CI 0.38-0.91) in women. Dairy food intake was significantly associated with a lower risk of type 2 diabetes in women only. CONCLUSIONS/INTERPRETATION: Calcium and vitamin D may not be independently associated with type 2 diabetes risk. Our finding suggesting a joint action of these nutrients against type 2 diabetes warrants further investigation.