Calcium intake and bone mineral density in chilean adolescents with complete pubertal development

Abstract

Background: In adolescents, the recommended daily intake (RDI) of calcium is 1,300 mg. In Chile, the latest National Survey of Food Consumption showed that the median total calcium intake was less than half of the RDI. An adequate intake of calcium in adolescence negatively affects BMD. Aim: To determine the association of calcium intake and nutritional status with bone mineral density (BMD) in male and female adolescents with completed pubertal development (Tanner 5). Methods: Cross-sectional study in a random sample of 79 male and female adolescents, ages 17-18. Participants were healthy, Tanner stage 5, and BMI <35 kg/m2. Three 24-hour recall questionnaires determined food intake. Weight, height, and waist circumference were measured, and BMI was estimated. Bone mineral density (BMD) was also measured. Results: Sixty-eight percent of adolescents had less than 50% of the recommended daily intake (RDI) for calcium. Mean calcium intake was 658±328mg/d and 568±299 mg/d in males and females, respectively. In both sexes, the mean standardized BMD was normal or >-1 SD. BMD was higher in obese participants compared to normal-weight adolescents (1.05±0.85 vs 0.33±0.86; P= 0.04), although no differences in nutrients and food intake. Calcium intake was unrelated to total bone mass and unstandardized BMD. Conclusions: In our sample of adolescents with complete pubertal development, there was no relationship between calcium intake and bone mineralization levels. There was a significant relationship between bone mineralization and nutritional status, with BMD being higher in adolescents with obesity.