Bone mineral density and body composition of collegiate modern dancers

This study investigates body composition (BC), bone mineral density (BMD), eating behaviors, and menstrual dysfunction in collegiate modern dancers. Thirty-one female collegiate modern dance majors (D), 18 to 25 years of age, and 30 age-matched controls (C) participated in the study. BC and BMD were measured using dual energy x-ray absorptiometry (DXA). Upper and lower body strength was assessed by chest and leg press one-repetition maximum tests. Participants completed three-day food records, and the diet was analyzed using nutritional software. Menstrual dysfunction (MD) and history of eating disorder (ED) data were collected via questionnaires. BC and BMD variables were analyzed using MANCOVA and frequency of ED and MD by Chi-Square analysis. BMD was greater in D than C at the spine (1.302 ± 0.135 g/cm(2) vs. 1.245 ± 0.098 g/cm(2)), and both the right hip (1.163 ± 0.111 g/cm(2) vs. 1.099 ± 0.106 g/cm(2)) and left hip (1.160 ± 0.114 g/cm(2) vs. 1.101 ± 0.104 g/cm(2); p ≤ 0.05). Total body fat percentage was lower in D than C (25.9 ± 4.2% vs. 32.0 ± 5.9%; p ≤ 0.05), and percent of fat distributed in the android region was also lower in D than C (28.0 ± 6.2% vs. 37.6 ± 8.6%; p ≤ 0.05). With regard to diet composition, only percent fat intake was lower in D than C (27.54 ± 6.8% vs. 31.5 ± 7.4%, p ≤ 0.05). A greater incidence of ED was reported by D than C (12.9% vs. 0%; p ≤ 0.05), as well as a greater incidence of secondary amenorrhea (41.9% vs 13.3%; p ≤ 0.05). No differences were found for incidence of primary amenorrhea, oligomenorrhea, or use of birth control. Strength values were higher in D than C for both chest press (30.1 ± 0.9 kg vs. 28.4 ± 1.0 kg; p ≤ 0.05) and leg press (170.7 ± 4.2 kg vs.163.1 ± 3.9 kg; p ≤ 0.05). It is concluded that the dancers in our study had a healthy body weight, yet reported a higher incidence of eating disorders and menstrual dysfunction, than non-dancers. These dancers' higher BMD may be attributable to the mechanical loading and increased strength associated with practicing modern dance. Further, modern dancers had lower centrally located body fat, which decreases the risk for cardiovascular and metabolic diseases.