The effects of calcium supplementation on ambulatory blood pressure in African-American adolescents.

This longitudinal trial investigated the effects of calcium supplementation on the mean 24-hour blood pressure in African-American adolescents. Subjects were self-identified African-American adolescents from a high school in a suburb of Los Angeles, California. The subjects were randomly placed in a placebo or treatment group (placebo versus 1.5 g of calcium/day x 4 weeks). Follow-up mean 24-hour ambulatory blood pressure (ABP) for both the treatment and control groups was lower than the baseline mean 24-hour ABP. In the treatment group, there was a decrease of 2.2 mm Hg in the mean systolic blood pressure and 0.7 mm Hg in the diastolic blood pressure. Relative to the placebo group, the net change in ABP was -1.7 mm Hg for systolic blood pressure and -0.5 mm Hg for the diastolic blood pressure. There was no statistically significant effect of calcium supplementation on the 24-hour mean ABP. The net effect of supplementation on ABP during waking and sleeping hours also was not significant.