The effect of dietary calcium intake on bone mineral density in healthy adolescent girls and young women in Southern Italy

Background The association between forearm bone mineral areal density (BMD) and dietary calcium, anthropometric characteristics, puberty, and physical activity was studied for the first time in 200 girls (aged 11-15 years) and 100 women (aged 20-23 years) living in Southern Italy. Methods The BMD was assessed by dual energy x-ray absorptiometry at ultradistal (ud) and proximal (pr) radial sites and dietary calcium was evaluated using Food Frequency Questionnaires and detailed 3-day food records. Results For population samples grouped according to low and high calcium intake levels, forearm densities were quite similar among both girls and women. Independently of calcium intake, girls displayed strong correlations between ud/pr-BMD and age, bone age, weight, height and BMI. Furthermore, in girls of similar age and BMT, radial densities were substantially increased following menarche. Positive relationships between weight, BMI and both ud/pr-BMD were only evident in women with high calcium intake. Conclusions This study showed that different calcium intake values do not appear to affect forearm mineral densities at the ages investigated, however puberty represents the major event in radial bone mass acquisition during adolescence.