EFFECT OF CALCIUM SUPPLEMENTATION ON BLOOD-PRESSURE IN CHILDREN

Objective: To evaluate the effect of calcium supplementation on blood pressure in children. Design: Randomized, double-masked, placebo-contr olled trial. Setting and participants: One hundred one fifth-grade stu dents in one inner-city school. Intervention: Each child consumed 480 ml of juice beverages, containing either no calcium or 600 mg calcium (as calcium citrate malate) daily for 12 weeks. Measurements: At basel ine we obtained nutrient data from three sets of 2-day food records on each subject. We measured blood pressure four times on each of three weekly sittings at baseline and at follow-up. Using multiple linear re gression analysis, we compared mean blood pressure change in the inter vention group with that in the placebo group. Results: There were 50 g irls and 51 boys; 61 subjects were black, At baseline, mean age was 11 .0 years, systolic and diastolic blood pressures were 101.7 and 57.7 m m Hg, daily total energy intake was 1966 kcal, and calcium intake was 827 mg. With control for age, height, hours of television watched, and baseline blood pressure, systolic blood pressure increased 1.0 mm Hg in the intervention group and 2.8 mm Hg in the placebo group (effect e stimate = -1.8 mm Hg; 95% confidence interval -4.0, 0.3). In black sub jects the intervention effect estimate was -2.0 mm Hg (95% confidence interval -4.4, 0.4). From lowest to highest quartile of baseline calci um intake (per 1000 kcal), the intervention effect estimates were -3.5 , -2.8, -1.3, and 0.0 mm Hg (p for trend = 0.009), There was little ef fect on diastolic blood pressure. Conclusion: These data suggest a blo od pressure-lowering effect of calcium supplementation in children, es pecially in subjects with low baseline calcium intake.