Bone Abstracts

Objective: To evaluate the bone mineral density (BMD) of the axial and appendicular skeleton in a group of collegiate dance students undergoing intensive training between a 24 months interval and to correlate these changes to the presence or absence of apparent athlete triad syndrome (ATS).

Methods: Forty full time collegiate dance students were recruited from a tertiary Performing Arts Institute. All subjects had basic anthropometric measurements, a full hormonal profile, pelvic ultrasound, bio-impedance estimation of body fat, and dual energy X-ray absorptiometry (DXA) and quantitative peripheral CT scans (pQCT) to determine bone density. The measurements were then repeated 22–24 months after the initial assessment, Those who had persistent oligo/amenorrhoea and were underweight with a BMI <18.5 kg/cm² were categorized as having apparent ATS. The measurements were compared to a group of non-exercising eumenorrheic adolescents recruited from the a general gynaecology clinic undergoing similar interval measurements.

Results: A total of 40 dance students and 21 control subjects were analysed. The mean age of the exercising (n=40) and non-excising subjects (n=21) were similar (18.4 vs 18.7 years). Comparing the interval changes at the 24-month reassessment, the exercising group showed a larger interval increment in lumbar spine BMD (0.068 vs 0.016 g/cm², P=0.001) as well hip BMD values (neck of femur 0.0439 vs 0.008 g/cm²; trochanter 0.023 vs 0.016 g/cm² and Ward’s triangle 0.035 vs 0.010 g/cm²; P≤0.001). Volumetric BMD also showed similar trends (distal radius core BMD 21.2 vs 13.1 g/cm³ and distal tibia core 20.5 vs 14 g/cm³, P=0.001). When dance students with (n=13) or without apparent ATS (n=27) were compared, no significant differences were seen in axial BMD values, marginally lower radial core BMD (16.3 vs 23.5 g/cm³, P=0.029) and tibial core BMD (16.8 vs 22.2 g/cm³, P=0.048) increments were seen in the ATS group.

Conclusion: Young women undergoing regular intensive weight-bearing exercises as in the collegiate dancers here studied have higher BMD increments as compared to non-exercising women. Even in the presence of apparent ATS, BMD increments, though somewhat attenuated, were significantly higher than non-exercising controls.