APPENDICULAR BONE MASS IN CHILDREN WITH A HIGH PREVALENCE OF LOW DIETARY CALCIUM INTAKES

We have previously documented evidence of dietary calcium deficiency i n black children living in a rural community in the eastern part of So uth Africa, The present study determined the bone mass of the distal o ne-third of the radius in a random sample of children living in the sa me community and compared their bone mass measurements with those of b lack children living in a similar rural community hut without evidence of dietary calcium deficiency, Further, factors (weight, height, seru m corrected total calcium, phosphorus, and alkaline phosphatase [ALP]) that might influence appendicular bone mass were assessed and correla ted with the bone mass measurements. A random sample of 306 boys and 3 45 girls between the ages of 1 and 20 years were included In the study , Hypocalcemia was found in 6.5% of the boys and 5% of the girls, whil e elevated ALP values mere recorded in 20 and 26% of the boys and girl s, respectively, After adjusting for differences in age, weight, and h eight, bone mineral density (BMD) and bone mineral apparent density (B MAD) were significantly lower and bone width (BW) greater in study tha n control children, In a stepwise regression analysis, weight and/or h eight accounted for the majority of the observed variance in BMC, BW, and BMD; however, a significant effect of serum calcium (positively) a nd ALP (negatively) on BMC and BMD was also found. In boys, but not gi rls, serum ALP also had a positive effect on BW, BMAD was negatively c orrelated to ALP and positively correlated to serum calcium in both bo ys and girls, Those children with hypocalcemia or elevated ALP levels had significantly lower RMC, BMD, and BMAD and a trend toward greater BW than children with normal biochemistry. The findings suggest that l ow dietary calcium intake may have a detrimental effect on appendicula r bone density in rural black children,Whether or not these effects ar e disadvantageous in the long-term is not known.