BONE MINERALIZATION OF SCHOOL AGE CHILDREN ACCORDING TO CALCIUM INTAKE

Abstract

Nutrition is one of the factors that influences bone mineralization (BM). We have shown that the Chilean teenager has a low calcium intake during a period of rapid calcium accretion, which may favor osteoporosis in adult life. Thus, we evaluated the influence of a low calcium intake on BM in school age children. We studied 36 children with calcium intakes below the recommended allowance (RDA) and 28 controls of the same age and sex with an adequate calcium intake. Calcium intake was measured by three 24 hour recollection surveys, the percentage of adequation of weight for height (W/H) according to WHO tables, and puberal development was assessed by the method of Tanner. Bone mineral density (BMD) and total bone mass (TBM) were determined in whde body, spine and hip, with a Norland densitometer (Gd 156). The group with calcium intake below 50% had a lower % of adequation of height for age (97.7 ± 4.0%), TBM (98.9 ± 17.9) and BMD (97.8 ± 11.1%) in whole body compared with the group with intake over 100% (115.9 ± 17.4; 109.7 ± 18.0 and 104.7 ± 11.1%, respectively). In spine and hip there was a clear tendency for a lower TBM and BMD, which did not reach statistical significance. The recollection survey showed a lower protein intake in the group with low calcium intake compared with controls. The influence of isolated calcium deficit or in combination with protein deficit upon skeletal mineralization is discussed.