Calcium, vitamin D and dairy intake in relation to type 2 diabetes risk in a Japanese cohort.
OBJECTIVE
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
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.
Kirii
K
K
Department of Epidemiology and International Health, Research Institute, International Medical Center of Japan, Tokyo, Japan.
Mizoue
T
T
Iso
H
H
Takahashi
Y
Y
Kato
M
M
Inoue
M
M
Noda
M
M
Tsugane
S
S
D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015331:Cohort Studies; D003611:Dairy Products; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control; D005247:Feeding Behavior; D005260:Female; D006306:Health Surveys; D006801:Humans; D007328:Insulin / Q000502:physiology; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000502:physiology; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000378:metabolism* / Q000494:pharmacology
D007328:Insulin; D014807:Vitamin D; D002118:Calcium