Bone mineral density in young active females: the case of dancers

The aim of the study was to evaluate the combined effect of several environmental factors on bone mineral density (BMD) in a group of highly active young women. Body composition, total body and regional (arms, legs and trunk) BMD, dietary intake, menstrual status, training habits, and eating attitudes were assessed in 37 professional dance students, aged 18 to 26 years. Dancers had higher BMD values compared to age- and weight-matched reference population (mean total body BMD: 1.185 g/cm2, 9% higher than reference values). No differences were detected between currently eumenorrheic and noneumenorrheic dancers; subjects who encountered menstrual problems during adolescence had significantly lower BMD values compared to counterparts who did not. Regarding dietary intake, dancers in the highest quartile of calcium intake (1323 +/-113 mg/d) exhibited significantly higher total BMD values than subjects in the other 3 quartiles (p =.04). A moderate inverse relationship was found between protein intake and total BMD, after controlling for energy and calcium intake (r = - 0.37). Fat-free soft mass was the only significant predictor of total BMD, explaining 20% of the variance. High levels of calcium intake were associated with high total BMD values. These results confirm the beneficial role of long-term and intensive physical activity on BMD and further suggest that dancers are not at a greater risk compared to the general population for developing osteoporosis, despite their menstrual and eating problems.