A meta-analysis of bone mineral density in collegiate female athletes.

PURPOSE In a number of small studies focused on one or two sports, exercise and competitive level has been observed to favor attainment of higher bone mineral density (BMD) in otherwise healthy athletes. We analyzed merged data from 10 studies to determine the effects of competitive level on upper extremity BMD in female athletes across multiple sports. METHODS This study is a meta-analysis of 10 articles reporting results of similar case-control and cross-sectional studies of BMD in female athletes and nonathletes reporting an effect of athletic participation level. Upper extremity BMD was modeled as an outcome of the level of athleticism using a categorical weighted least squares model and controlling for upper-body impact, age, and body mass index. RESULTS Upper extremity BMD significantly increased for each level of participation (β = 0.140; 95% CI, 0.047-0.234), Age and body mass index approached significance but the level of upper extremity impact was not significant in the final model. CONCLUSIONS Clinicians may see iteratively greater BMD in female patients who compete at increasingly intense athletic levels, with elite athletes having much higher BMD than other patients who are either active or not. Further research is needed to identify direction and causality of the relationship between competitive level and BMD.