Background: The present epidemiologic study was conducted in Tromso, Northern Norway, in 1994-1995.
Objective: The objective was to evaluate the relation between calcium intake from dairy products and the intake of vitamin D on systolic and diastolic blood pressure.
Design: Subjects who were taking drugs for hypertension or heart disease, those taking calcium tablets, subjects reporting cardiovascular disease, and pregnant women were excluded, leaving 7543 men and 8053 women aged 25-69 y for analysis. Calcium and vitamin D intakes were calculated from a food-frequency questionnaire.
Results: After correction for age, body mass index, alcohol and coffee consumption, physical activity, cigarette smoking, and vitamin D intake, there was a significant linear decrease in systolic and diastolic blood pressure with increasing dairy calcium intake in both sexes (P < 0.05). However, the difference in blood pressure between subjects with the highest and those with the lowest calcium intake was </=1-3 mm Hg. Similarly, with increasing blood pressure there was a significant (P < 0.001) linear decrease in age-adjusted calcium intake from dairy sources; the difference between the highest and the lowest blood pressure groups was 3-10%. Vitamin D intake had no significant effect on blood pressure.
Conclusions: There is a negative association between calcium intake from dairy products and blood pressure. However, although the effect of calcium on blood pressure appears to be small, calcium could have a significant effect on primary prevention of cardiovascular diseases.