Risk Behaviors for Eating Disorders in Brazilian Dancers

Body Composition, Eating Habits, and Disordered Eating Behaviors among Adolescent Classical Ballet Dancers and Controls

Adolescent classical ballet dancers are nutritionally vulnerable, as they try to retain a lean body shape during a life period of high nutritional requirements due to rapid growth. Studies conducted on adult dancers have indicated a high risk for the development of disordered eating behaviors (DEBs), but research on adolescent dancers remains scarce. The aim of the present case-control study was to compare the body composition, dietary habits, and DEBs of female adolescent classical ballet dancers and their non-dancer same-sex peers. Self-reported questionnaires, namely the Eating Attitudes Test-26 (EAT-26) and a 19-item Food Frequency Questionnaire (FFQ), were used for the assessment of habitual diet and DEBs. The assessment of body composition included the measurements of body weight, height, body circumference, and skinfolds and bioelectrical impedance analysis (BIA). The results indicate that the dancers were leaner than the controls, with lower weight, BMIs, and hip and arm circumferences, leaner skinfolds, and less fat mass. No differences were observed between the two groups regarding eating habits and the EAT-26 scores, but almost 1 out of 4 (23.3%) participants scored ≥ 20, indicative of DEBs. Participants with an EAT-26 score ≥ 20 had significantly higher body weight, BMIs, body circumferences, fat mass, and fat-free mass than those with a score < 20. Adolescents must be educated on nutrition and healthy methods to control body weight through evidence-based information and programs, and whenever appropriate, also through individual counseling by the appropriate health professionals.

Cross-validation of prediction equations for estimating body composition in ballet dancers

Introduction

In sports related to low body weight, such as classical ballet, the assessment of body composition is important for monitoring performance and health status. This study aimed to cross-validate anthropometry and bioelectrical impedance (BIA) predictive equations for estimating body composition of non-professional classical ballet dancers, using dual-energy-X-ray absorptiometry (DXA) as a reference method.

Materials and methods

Thirty-seven female non-professional classical dancers (median age of 19 years), at intermediate/advanced level, were evaluated in a cross-sectional study. Body composition was evaluated by DXA, anthropometry and tetrapolar BIA. Twenty different predictive equations of anthropometry (n = 8) and BIA (n = 12) were used to estimate Body Fat (BF) and Fat-Free Mass (FFM), testing their validity against DXA using the Bland-Altman statistics.

Results

For BF estimated by anthropometry equations, just one equation showed agreement with DXA (r = 0.852, p < 0.0005; p = 0.600 for one sample T-test). According to the Bland-Altman analysis, this equation also showed validity, with the absence of proportional bias. Regarding the predictive BIA equations tested, none were valid for our study group.

Conclusion

Only one of the anthropometric equations, the one proposed by Durnin and Womerley (1974), but none of the BIA equations analyzed, was valid for the evaluation of body composition of the studied classical dancers. Our results emphasize the importance of previous cross-validation of existing equations or the development of specific equations for body composition assessment in specific populations.

Low RMRratio as a Surrogate Marker for Energy Deficiency, the Choice of Predictive Equation Vital for Correctly Identifying Male and Female Ballet Dancers at Risk

Ballet dancers are reported to have an increased risk for energy deficiency with or without disordered eating behavior. A low ratio between measured (m) and predicted (p) resting metabolic rate (RMRratio < 0.90) is a recognized surrogate marker for energy deficiency. We aimed to evaluate the prevalence of suppressed RMR using different methods to calculate pRMR and to explore associations with additional markers of energy deficiency. Female (n = 20) and male (n = 20) professional ballet dancers, 19–35 years of age, were enrolled. mRMR was assessed by respiratory calorimetry (ventilated open hood). pRMR was determined using the Cunningham and Harris–Benedict equations, and different tissue compartments derived from whole-body dual-energy X-ray absorptiometry assessment. The protocol further included assessment of body composition and bone mineral density, blood pressure, disordered eating (Eating Disorder Inventory-3), and for females, the Low Energy Availability in Females Questionnaire. The prevalence of suppressed RMR was generally high but also clearly dependent on the method used to calculate pRMR, ranging from 25% to 80% in males and 35% to 100% in females. Five percent had low bone mineral density, whereas 10% had disordered eating and 25% had hypotension. Forty percent of females had elevated Low Energy Availability in Females Questionnaire score and 50% were underweight. Suppressed RMR was associated with elevated Low Energy Availability in Females Questionnaire score in females and with higher training volume in males. In conclusion, professional ballet dancers are at risk for energy deficiency. The number of identified dancers at risk varies greatly depending on the method used to predict RMR when using RMRratio as a marker for energy deficiency.

Factors Dancers Associate with their Body Dissatisfaction

Body dissatisfaction constitutes an important factor in the development of eating pathologies, particularly among dancers. The aim of this research was to test the factors that dancers identified as relevant to their body dissatisfaction using an exploratory mixed method design. Participants were 369 dancers from two Spanish dance conservatories. Questionnaires assessed body dissatisfaction, abnormal eating attitudes and behaviors, and risk factors to eating disorders in the dance domain. Nine factors were found; the "teacher", the "uniform", and the "mirrors" were the most common. Individuals with a greater likelihood of developing an eating disorder identified teacherś influence as a key factor in their body dissatisfaction. Specifically, ballet dancers were more likely to indicate that teachers were a negative influence compared to students in other dance genres (contemporary, flamenco, and Spanish dance). Programs to reduce negative body image and improve positive body image in dance conservatories are needed, specifically focusing on teachers.

Assessment of DNA damage in a group of professional dancers during a 10-month dancing season

Despite the numerous health benefits of physical activity, some studies reported that increased intensity and duration may induce oxidative stress in several cellular components including DNA. The aim of this study was to assess the level of basal DNA damage as well as oxidative DNA damage in a group of professional dancers before and after a 10-month dancing season. A group of individuals from general population was also assessed as a control. The alkaline version of the comet assay was the method selected to measure both basal DNA damage and oxidative stress, since this method quantifies both endpoints. In order to measure oxidative stress, the comet assay was coupled with a lesion-specific endonuclease (formamidopyrimidine glycosylase) to detect oxidized purines. The levels of oxidative DNA damage in dancers were significantly increased after the dancing season. Pre-season levels of oxidative DNA damage were lower in dancers than those obtained from the general population, suggesting an adaptation of antioxidant system in dancers. Results of the present biomonitoring study indicate the need for more effective measures to protect ballet dancers from potentially occupational health risks related to regular intensive physical exercise.

Comparison of nutritional intake, body composition, bone mineral density, and isokinetic strength in collegiate female dancers

This study compared nutritional intake, body composition, bone mineral density, and isokinetic strength by dance type in collegiate female dancers. The study subjects included Korean dancers (n=12), ballet dancers (n=13), contemporary dancers (n=8), and controls (n=12). Nutritional intake was estimated using the Computer Aided Nutritional Analysis Program. Body composition and bone mineral density were measured using dual-energy X-ray absorptiometry. Isokinetic knee joint strength was measured by Cybex 770-NORM. All statistical analyses were performed by SAS 9.2. Means and standard deviations were calculated using descriptive statistics. One-way analysis of variance was applied to evaluate nutritional intake, body composition, bone mineral density, and isokinetic strength differences. Duncan multiple range test was used for post hoc testing. A level of significance was set at P<0.05. The study results indicated no significant differences in nutritional in-take among dancer types. Despite no significant differences in body composition among dancer types, contemporary and ballet dancers had lower body fat percentages than controls (P<0.05). No significant differences were seen in bone mineral density and bone mineral contents among dancer types. No significant differences were found in isokinetic strength in right or left knee flexion and extension at 60°/sec (P<0.05). There were significant differences in body composition and isokinetic strength between dancer groups and the control group. Further studies of different professional dance type and more scientific methods of dance training are needed.

Prevalence of eating disorders amongst dancers: a systemic review and meta-analysis

Eating disorders in dancers are thought to be common, but the exact rates remain to be clarified. The aim of this study is to systematically compile and analyse the rates of eating disorders in dancers. A literature search, appraisal and meta-analysis were conducted. Thirty-three relevant studies were published between 1966 and 2013 with sufficient data for extraction. Primary data were extracted as raw numbers or confidence intervals. Risk ratios and 95% confidence intervals were calculated for controlled studies. The overall prevalence of eating disorders was 12.0% (16.4% for ballet dancers), 2.0% (4% for ballet dancers) for anorexia, 4.4% (2% for ballet dancers) for bulimia and 9.5% (14.9% for ballet dancers) for eating disorders not otherwise specified (EDNOS). The dancer group had higher mean scores on the EAT-26 and the Eating Disorder Inventory subscales. Dancers, in general, had a higher risk of suffering from eating disorders in general, anorexia nervosa and EDNOS, but no higher risk of suffering from bulimia nervosa. The study concluded that as dancers had a three times higher risk of suffering from eating disorders, particularly anorexia nervosa and EDNOS, specifically designed services for this population should be considered.

Comparative validity of the chinese versions of the bulimic inventory test edinburgh and eating attitudes test for DSM-IV eating disorders among high school dance and nondance students in Taiwan

OBJECTIVES

To compare the validity of the Eating Attitudes Test (EAT) and the Bulimic Investigatory Test Edinburgh (BITE) as screening tools for eating disorders (EDs), and to identify a new threshold for each questionnaire to detect ED cases among dance and nondance students.

METHOD

Dance students enrolled in high schools with gifted dance programs and nondance students randomly chosen from the same or nearby schools were invited to participate in a 2-phase ED survey. Participants completed the EAT and BITE questionnaires in the first phase. All participants who screened positive and 10% of the participants who screened negative were interviewed blindly using the Structured Clinical Interview for DSM-IV-TR Axis I Disorders Patient Edition.

RESULTS

The BITE had better accuracy than the EAT in detecting ED in general among both dance and non-dance students. BITE scores of 19 and 16 were the optimal cutoff values for determining ED among dance and nondance students, respectively. The optimal cutoff value for the EAT to diagnose an ED was 19 for dance students and 12 for nondance students. Both questionnaires showed higher sensitivity and lower specificity in dance students than nondance students at the same cutoff points.

DISCUSSION

The BITE had better diagnostic performance than the EAT in this nonclinical population, although its ability to detect restrictive behaviors is likely as limited as that of the EAT. Plausible explanations for these results and limitations of this study are discussed in the text.