Increased Prevalence of Scoliosis in Female Professional Ballet Performers

Background: Musculoskeletal abnormalities have been reported among female professional ballet performers due, in part, to intrinsic predispositions related to joint and/or connective tissue laxity and extrinsic effectors such as reduced energy availability, low body mass, and high training volumes that may increase the risk of developing idiopathic scoliosis (IS). The purpose of this investigation was to characterize IS prevalence in this population. We hypothesized that there would be elevated prevalence in female performers and that those with IS would exhibit reduced bone mineral density (BMD), body mass, fat mass, and lean mass. Methods: A retrospective analysis of whole-body anteroposterior radiographs was performed on 98 professional ballet dancers (49 male performers [mean age, 25 ± 6 years] and 49 female performers [mean age, 27 ± 5 years]) from a single company. Body composition and BMD were assessed via dual x-ray absorptiometry. The criterion for IS was defined as a Cobb angle of >10°. The frequency of IS was plotted against general-population norms. A t test was used to compare demographic characteristics, anthropometrics, and BMD between performers with and without IS and to compare the Cobb angles between sexes. A Fisher exact test was used to compare the IS prevalence between sexes. The Type-I error was set at a = 0.05. Results: Compared with male performers, female performers had greater spinal asymmetry (mean Cobb angle, 7.98° [95% confidence interval (CI) width, 1.76°] for men and 4.02° [95% CI width, 1.00°] for women; p = 0.027). The prevalence of IS among male performers (3 [6.12%] of 49) was comparable with the general-population norms (0.31% to 5.60%). Women had an elevated prevalence of IS compared with men (10 [20.41%] of 49; p = 0.037) and with general-population norms (0.65% to 8.90%). Among women, performers with IS were observed to have a reduced percentage of body fat (p = 0.021) and reduced fat mass (p = 0.040) compared with performers without IS. Conclusions: Female professional ballet performers demonstrate a heightened prevalence of IS that, in addition to intrinsic predisposition, is associated with modifiable factors such as reduced fat mass commonly associated with reduced energy availability known to impact musculoskeletal health in athletes. Future investigations should seek to determine the prevalence of IS in other young female athlete populations commonly exposed to high degrees of activity and reduced energy availability.