The effect of calcium and vitamin D supplementation on bone health of male Jockeys

Objectives Engagement in high volumes of physical activity coupled with energy restriction during periods of musculoskeletal development may compromise bone health. Jockeys limit caloric intakes on a weekly basis often from their mid-to-late teens. The aim of this study was to establish whether calcium and vitamin D supplementation would improve bone turnover markers (BTM) and non-weight bearing bone properties of young male jockeys. Design A six-month randomised, double-blinded, placebo-controlled trial with two groups of apprentice male jockeys was conducted. Methods Participants (age 20.18 Â± 3.23 years) were supplemented with 800 mg of calcium and 400 IU of vitamin D (n = 8) or a placebo (n = 9) daily. Bone properties were assessed at the ultra-distal (4%) and proximal (66%) radius using pQCT at baseline and six months. Vitamin D, P1NP and CTX were assessed. Results ANCOVA results for blood-borne markers indicated higher vitamin D levels (18.1%, p = 0.014, partial η2 = 0.38) and lower CTX (ng·L−1) (−24.8%, p = 0.011, partial η2 = 0.40) in the supplemented group with no differences observed in P1NP. Analysis of bone variables indicated no between group differences in either trabecular or cortical bone properties at the 4% and 66% sites post-intervention. Conclusions This trial is the first to examine the efficacy of calcium and vitamin D supplementation in improving non-weight bearing bone properties in a young male athletic population. Results indicate positive alterations to bone metabolism; however, longer duration or higher dosage appears to be required to detect changes in bone material properties at the radius. Further examination of such interventions in weight-restricted athletes is warranted.