title: Prevalence of low bone mineral density in female dancers.
abstract: OBJECTIVE
  While some authors report that dancers have reduced bone mineral density (BMD) and increased risk of osteoporosis, others have stressed the positive effects of dance training on developing healthy BMD. Given the existing controversy, the aim of this systematic review was to examine the best evidence-based information available in relation to female dancers.
  
  
  METHODS
  Four databases (Web of Science, PubMed, EBSCO, Scopus) and two dance science journals (Journal of Dance Medicine and Science and Medical Problems of Performing Artists) were searched for relevant material using the keywords "dance", "ballet", "BMD", "bone density", "osteoporosis" and "female athlete triad syndrome". A total of 257 abstracts were screened using selected inclusion (studies involving bone measurements in dancers) and exclusion (editorials, opinion papers, chapters in books, narrative reviews and non-English language papers) criteria according to PRISMA guidelines. Following the above screening, a total of 108 abstracts were identified as potentially relevant. After the exclusion of conference proceedings, review papers, studies focusing only in male dancers and studies in which dancers' information were combined with other athletes, the eligible papers were subsequently assessed using the GRADE system and grouped according to: (1) prevalence of low BMD and associated factors, (2) incidence of low BMD and risk factors, (3) prevention/treatment of low BMD in dancers, and (4) other studies.
  
  
  RESULTS
  Of the 257 abstracts that were initially screened, only 35 studies were finally considered. Only one of these 35 was of high quality, while the remaining 34 were of relatively low quality. Seven studies reported prevalence of low BMD and associated factors, 10 reported associated factors with no prevalence data, while one reported prevalence with no associated factors data. One study cited risk factors, while another one elaborated on the treatment of low BMD in dancers. The remaining 15 studies were classified as "other studies".
  
  
  CONCLUSIONS
  It remains unclear whether low BMD is prevalent in female dancers. The present review highlights the need for high-quality BMD research in this area.
authors.affiliation: Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal, tania_amorim@hotmail.com.
authors.forename: Tânia
authors.initials: T
authors.lastname: Amorim
authors.forename: Matthew
authors.initials: M
authors.lastname: Wyon
authors.forename: José
authors.initials: J
authors.lastname: Maia
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Machado
authors.forename: Franklim
authors.initials: F
authors.lastname: Marques
authors.forename: George S
authors.initials: GS
authors.lastname: Metsios
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Flouris
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
mesh_terms: D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D003615:Dancing / Q000502:physiology*; D005260:Female; D006801:Humans; D015994:Incidence; D010024:Osteoporosis / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors