DOUBLE-BLIND, CONTROLLED CALCIUM SUPPLEMENTATION AND BONE-MINERAL ACCRETION IN CHILDREN ACCUSTOMED TO A LOW-CALCIUM DIET

A randomized, double-blind, controlled calcium supplementation trial w as conducted for 18 mo to determine its effects on bone acquisition an d height increment in 162 7-y-old Chinese children (87 boys and 75 gir ls) with habitually low calcium intakes (280 mg/d). Distal one-third r adial bone mineral content (BMC), area bone density (BMC/bone width), and height were evaluated every 6 mo. Baseline dietary intakes, serum 25-hydroxycholecalciferol , and physical activity were determined. The study group received 300 mg Ca/d as calcium carbonate; control subjec ts received placebo tablets. After 18 mo the study group had significa ntly greater gains in BMC (16.5% vs 13.97%; P = 0.02) and BMC/bone wid th (9.45% vs 6.31%; P = 0.0008) than the control subjects. The finding s confirm a positive effect of calcium intake on bone acquisition but no effect on height increment. Whether a higher bone mass attained at age 8-9 y would be maintained and beneficial to future peak bone mass requires longitudinal investigation. Further study is warranted to det ermine calcium requirements for Chinese children.