Bone mineral acquisition in low calcium intake children following the withdrawal of calcium supplement.
Our recent 18-month calcium supplementation trial demonstrated a significant increase in radial bone mineral mass in 7-year-old children with calcium intake approximately 300 mg/day (Am J Clin Nutr 1994; 60: 744-50). The persistence of higher bone mass after cessation of calcium supplementation is unknown. This is a follow-up study to investigate the lasting effect of calcium supplementation on bone acquisition. Subjects were 159 Chinese children aged 8.7 years. Distal one-third radial bone mineral content (BMC) and bone width (BW) were measured by single-photon absorptiometry. After 12 months, the significant difference in mean +/- SD percentage radial BMC disappeared between the study and control groups (7.34 +/- 6.77% vs 8.67 +/- 6.46%, p > 0.05). Dietary calcium intakes were similar between the groups. During the supplementation phase, the study group had 17.9% greater BMC gain than that of controls. In the follow-up phase, however, the study group had 16.1% less BMC gain than that of controls. It appears that an increased acquisition rate during the supplementation phase was almost balanced by a reduced acquisition rate during follow-up phase. Moreover, throughout the entire 30-month period, the overall BMC acquisition rates of the study and control groups were 25% and 23.8%, respectively. Hence, the overall acquisition rate of the study group was only 5% higher than that of controls. Therefore, the effect of calcium supplementation on bone mineral gain appears to reflect a transient reduction in bone turnover rate. Longer-term calcium trials are necessary to confirm whether a sustainable higher calcium intake throughout childhood will enhance peak bone mass.
Lee
W T
WT
Department of Paediatrics, Faculty of Medicine, Chinese University of Hong Kong, Shatin, Hong Kong.
Leung
S S
SS
Leung
D M
DM
Wang
S H
SH
Xu
Y C
YC
Zeng
W P
WP
Cheng
J C
JC
D001827:Body Height; D001835:Body Weight; D015519:Bone Density; D002113:Calcification, Physiologic; D002118:Calcium / Q000008:administration & dosage* / Q000172:deficiency*; D002648:Child; D002657:Child Development; D002664:Child Nutritional Physiological Phenomena; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male
D002118:Calcium