Calcium supplementation and bone mineral density in adolescent girls

Abstract

<h3>Objective.</h3> —To evaluate the effect of calcium supplementation on bone acquisition in adolescent white girls. <h3>Design.</h3> —A randomized, double-blind, placebo-controlled trial of the effect of 18 months of calcium supplementation on bone density and bone mass. <h3>Subjects.</h3> —Ninety-four girls with a mean age of 11.9+0.5 years at study entry. <h3>Setting.</h3> —University hospital in a small town. <h3>Interventions.</h3> —Calcium supplementation, 500 mg/d calcium as calcium citrate malate; controls received placebo pills. <h3>Main Outcome Measures.</h3> —Bone mineral density and bone mineral content of the lumbar spine and total body were measured by dual-energy x-ray absorptiometry and calcium excretion from 24-hour urine specimens. <h3>Results.</h3> —Calcium intake from dietary sources averaged 960 mg/d for the entire study group. The supplemented group received, on average, an additional 354 mg/d of calcium. The supplemented group compared with the placebo group had greater increases of lumbar spine bone density (18.7% vs 15.8%;<i>P</i>=.03), lumbar spine bone mineral content (39.4% vs 34.7%;<i>P</i>=.06), total body bone mineral density (9.6% vs 8.3%;<i>P</i>=.05), and 24-hour urinary calcium excretion (90.4 vs 72.9 mg/d;<i>P</i>=.02), respectively. <h3>Conclusions.</h3> —Increasing daily calcium intake from 80% of the recommended daily allowance to 110% via supplementation with calcium citrate malate resulted in significant increases in total body and spinal bone density in adolescent girls. The increase of 24 g of bone gain per year among the supplemented group translates to an additional 1.3% skeletal mass per year during adolescent growth, which may provide protection against future osteoporotic fracture. (<i>JAMA</i>. 1993;270:841-844)