title: Assessment of the bone quality of black female athletes using quantitative ultrasound.
abstract: OBJECTIVE
  The mean daily calcium intake of adult Nigerians is reportedly low, and animal studies have shown that exercise-induced changes in the bones of growing mice are gender specific. We therefore sought to describe calcaneal broadband ultrasound attenuation (BUA), speed of sound (SOS), stiffness index (SI) and SI-based T-scores in a cohort of Nigerian female athletes; to assess the correlation of SI with energy expenditure; and to compare mean SI values between sports.
  
  
  METHODS
  We recruited 52 female athletes in 10 sporting categories, and recorded their anthropometric data. Activity levels were estimated using a questionnaire. Bone density was assessed using calcaneal ultrasound.
  
  
  RESULTS
  The mean age of athletes was 21+/-4 years (range 15-39 years). The mean body mass index (BMI) was 22.0+/-3.5 kg/m2, and was not different between the sub-group of footballers/runners (21.3+/-1.7 kg/m2) and other athletes (23.1+/-4.8 kg/m2, P=0.06). The mean energy expenditure was 32.2+/-9.5 kcal/kg/ day, and was not different between the sub-group of footballers/runners (30.8+/-9.2 kcal/kg/day) and other athletes (34.3+/-9.7 kcal/kg/day, P=0.19). The mean BUA of the athletes was 135+/-14 dB/MHz, the mean SOS was 1597+/-13 m/s, the mean SI was 118+/-15, and the median SI-based T-score was +1.1 (-1.6 to +3.53). The means of all ultrasound parameters were not significantly different between footballers/runners and other sportswomen.
  
  
  CONCLUSIONS
  Consistent physical training may improve calcaneal SI of black females by one, and potentially by as much as three T-score units. Training intensity, rather than the qualitative aspects of a sport, appears to be a major determinant of SI in female Nigerian athletes.
authors.affiliation: Department of Family Medicine, Jos University Teaching Hospital, Jos, Nigeria.
authors.forename: E P
authors.initials: EP
authors.lastname: Laabes
authors.forename: D J
authors.initials: DJ
authors.lastname: Vanderjagt
authors.forename: M O
authors.initials: MO
authors.lastname: Obadofin
authors.forename: A J
authors.initials: AJ
authors.lastname: Sendeht
authors.forename: R H
authors.initials: RH
authors.lastname: Glew
mesh_terms: D000293:Adolescent; D000328:Adult; D044383:Black People; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D002111:Calcaneus / Q000000981:diagnostic imaging* / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009549:Nigeria; D012189:Retrospective Studies; D013177:Sports / Q000502:physiology*; D011795:Surveys and Questionnaires; D014463:Ultrasonography; D055815:Young Adult