title: Modifiable lifestyle factors affecting bone health using calcaneus quantitative ultrasound in adolescent girls.
abstract: One hundred and fourteen girls were measured for calcaneus QUS (stiffness index score), calcium intake, weight, and total hours spent in physical activity (moderate to high-impact activities and low to no-impact activities). Multiple regression analysis indicated that hours spent in moderate to high-impact activities, current calcium intake, and weight significantly predicted SI.
  
  
  BACKGROUND
  To determine the influence of modifiable lifestyle factors on adolescent girls' bone health measured by calcaneus quantitative ultrasound (QUS).
  
  
  METHODS
  One hundred and fourteen girls, ages 14-18 (15.97 +/- .7), enrolled in high school physical education classes, were measured for calcaneus QUS (stiffness index score), height, weight, current calcium intake from 2-3 day food records, and estimated total hours spent in physical activity from kindergarten to present. Cumulative physical activity hours were separated into two classifications (according to their estimated strain from ground reaction force): moderate to high-impact activities and low to no-impact activities.
  
  
  RESULTS
  Pearson correlations between stiffness index (SI) and age, height, weight, current calcium intake, and hours spent in moderate to high-impact versus low to no-impact activities indicated a positive relationships between SI and weight (r = .259, p = .005), current calcium intake (r = .286, p = .002), and hours spent in moderate to high-impact activities (r = .451, p < .001). Multiple regression between SI and the above independent variables indicated that collectively, hours spent in moderate to high-impact activities, current calcium intake, and weight (r (2) = .363, p = <.001) significantly predicted SI.
  
  
  CONCLUSIONS
  Our data indicate that moderate to high-impact activities, current calcium intake, and weight positively influence bone properties of the calcaneus in adolescent girls.
authors.affiliation: Division of Nursing and Health Sciences, Lewis-Clark State College, 500 8th Ave, Lewiston, ID 83501, USA. marylou@lcsc.edu
authors.forename: M L
authors.initials: ML
authors.lastname: Robinson
authors.forename: K
authors.initials: K
authors.lastname: Winters-Stone
authors.forename: K
authors.initials: K
authors.lastname: Gabel
authors.forename: D
authors.initials: D
authors.lastname: Dolny
mesh_terms: D000293:Adolescent; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002111:Calcaneus / Q000000981:diagnostic imaging* / Q000502:physiology; D002136:Calcium, Dietary / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007061:Idaho / Q000453:epidemiology; D008019:Life Style / Q000208:ethnology; D014463:Ultrasonography; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D002136:Calcium, Dietary