ological 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 c timatcd using a validated food frequency questiom1aire. Logistic regression was used to assess the association between intake of these nutrients and self-repot1ed newly diagnosed type 2 diabetes.
Results During a 5 year follow-up, 1,114 ea cs 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'Yo CI 0.56-1.03) in women. Ilowcvcr, among partici pants with a higher vitamin D intake, calcimn intake was inversely associated with diabetes risk; the odds ratio for the highest vs lowest intake categories 'Nas 0.62 (95% Cl
0.41-0.94) in men and 0.59 (95% CI 0.38-0.91) in women.
Dairy food intake was si -,rnificantly 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