Bone mass of female dance students prior to professional dance training: A cross-sectional study

by Tânia Amorim, George S. Metsios, Matthew Wyon, Alan M. Nevill, Andreas D. Flouris, José Maia, Eduardo Teixeira, José Carlos Machado, Franklim Marques, Yiannis Koutedakis

Professional dancers are at risk of developing low bone mineral density (BMD). However, whether low BMD phenotypes already exist in pre-vocational dance students is relatively unknown.

To cross-sectionally assess bone mass parameters in female dance students selected for professional dance training (first year vocational dance students) in relation to aged- and sex-matched controls.

34 female selected for professional dance training (10.9yrs ±0.7) and 30 controls (11.1yrs ±0.5) were examined. Anthropometry, pubertal development (Tanner) and dietary data (3-day food diary) were recorded. BMD and bone mineral content (BMC) at forearm, femur neck (FN) and lumbar spine (LS) were assessed using Dual-Energy X-Ray Absorptiometry. Volumetric densities were estimated by calculating bone mineral apparent density (BMAD).

Dancers were mainly at Tanner pubertal stage I (vs. stage IV in controls, p<0.001), and demonstrated significantly lower body weight (p<0.001) and height (p<0.01) than controls. Calorie intake was not different between groups, but calcium intake was significantly greater in dancers (p<0.05). Dancers revealed a significantly lower BMC and BMD values at all anatomical sites (p<0.001), and significantly lower BMAD values at the LS and FN (p<0.001). When adjusted for covariates (body weight, height, pubertal development and calcium intake), dance students continued to display a significantly lower BMD and BMAD at the FN (p<0.05; p<0.001) at the forearm (p<0.01).

Before undergoing professional dance training, first year vocational dance students demonstrated inferior bone mass compared to controls. Longitudinal models are required to assess how bone health-status changes with time throughout professional training.