Association of Sport Participation and Calcium Intake with Bone Mineral Density in Children and Adolescents: A Cross-Sectional Study

Background: Sport participation has been shown to have a positive impact on bone mineral density (BMD) in children and adolescents. In fact, the type, intensity, and duration of sports activities may influence the magnitude of the effect on BMD. The aim of this study was to examine the effect of different sports on BMD in children and adolescents. Methods: We studied 90 children and adolescents (age 10.21 ± 2.96 years): 43 soccer players, 27 vocational dancers, and 20 active controls. In all subjects, bone mineral density at the lumbar spine (BMD-LS), at the femoral neck (BMD-FN), and at the total femur (BMD-TH) was measured. Moreover, their daily dietary calcium intake was assessed, and the presence of prior fractures was reported. Results: The values of the BMD-LS Z-score adjusted for height did not differ between the three groups: controls (BMD-LS Z-score values were 0.41 ± 1.26, 0.16 ± 0.94, and −0.14 ± 0.96 for soccer players, vocational dancers, and active controls, respectively). On the contrary, BMD-FN and BMD-TH were significantly higher in the soccer players group compared to the vocational dancers and active controls groups (BMD-FN Z-score values, adjusted for height, were 0.49 ± 1.35, −0.04 ± 0.84, and −0.63 ± 1.25 for soccer players, vocational dancers, and active controls, respectively). Soccer players with a history of fractures showed no reduced BMD values compared to those without previous fractures, whereas vocational dancers and active controls with fracture history had reduced BMD values. Conclusions: Consistent athletic involvement during the pre-pubertal and pubertal years significantly enhances bone mineral acquisition. Specifically, youth soccer players demonstrate superior BMD at the proximal femur compared to less active peers, underscoring the site-specific osteogenic effect of sport-related mechanical strain.