Dietary calcium and bone density in adolescent girls and young women in Europe

The objective of this study was to investigate the association between diet ary calcium intake and radial bone density among young women, over the whol e range of intake and at different levels of calcium intake, The study desi gn was a cross-sectional, observational multicenter investigation in six Eu ropean countries. One thousand one hundred and sixteen healthy Caucasian gi rls aged 11-15 Sears and 526 women aged 20-23 years participated, after hav ing been selected from larger population samples to represent a large range in calcium intake. Bone mineral density (BMD) was measured with dual-energ y X-ray absorptiometry at the ultradistal and middistal radius. Calcium int ake was assessed with 3-day food records. Other potential determinants of B MD were measured by anthropometry or questionnaires. Mean calcium intake am ong the girls varied between 609 mg/day in Italy and 1267 mg/day in Finland ; intakes for women were in a similar range. After adjustment for height, w eight, and age at menarche for the women, and adjustment for age, height, w eight, Tanner stage, and bone area for the girls, radial BMD at both sites did not significantly vary among quartiles of calcium intakes for both age groups. In multivariate linear regression, calcium was weakly positively as sociated with BMD at both sites in the girls (per 100 mg of calcium: beta = 0.57 mg/cm(2), p = 0.03 for middistal BMD and beta = 0.56 mg/cm(2), p = 0. 01 for ultradistal BMD). For middistal BMD, the association was observed pr edominantly in premenarcheal girls, The associations were no longer statist ically significant after full adjustment for all determinants of BMD, excep t again in pre-menarcheal girls. Radial BMD in the women was not associated with calcium intake, except after full adjustment for determinants of BMD, when ultradistal BMD became inversely associated with calcium intake (per 100 mg beta = -1.02, p = 0.03); this finding was due to results in one of t he countries and not found in other countries. There was no evidence for a different relation between calcium and BMD at different levels of intake; a lthough there was a positive association at calcium intake levels <600 mg/d ay, the interaction was not significant and there was no consistent trend o ver intake categories. These results do not support the hypothesis that die tary calcium is a determinant of peak BMD in European women, for a wide ran ge of intake. This study does not provide evidence that Recommended Dietary Allowances for calcium should be increased.