The association of intakes of vitamin D and calcium with blood pressure among women.

Blood pressure and its relationship to nutritional factors, particularly intakes of calcium and vitamin D, were evaluated among 86 women, aged 20-35 yr, and 222 women, aged 55-80 yr, who were not using diuretics. Observations were based on a study of bone density among women in two communities which included blood pressure determinations, a food frequency estimate of calcium intake, a 24-h dietary recall and an extensive supplement use history. There was no significant relationship between estimated current dietary calcium consumption and blood pressure in either age group. However, in younger women, there was a significant inverse relationship between estimated dietary intake of vitamin D and systolic blood pressure which remained significant (p = 0.0016) after adjusting for age, Quetelet index, alcohol consumption and calcium intake. Older women whose consumption of both vitamin D and calcium was less than the Recommended Dietary Allowance, 400 IU/day and 800 mg/day respectively, had a significantly higher systolic blood pressure (p = 0.0371) than their counterparts whose estimated intake met the RDA for at least one of the two nutrients. Vitamin D may be related to blood pressure through its regulation of calcium absorption from the gut or its interaction with parathyroid hormone in maintaining plasma calcium homeostasis.