title: Bone mass assessment in naval crew members by quantitative ultrasound technique.
abstract: OBJECTIVE
  Of necessity, naval crews live in confined spaces when on board warships, which may lead to decreased bone mass and to subsequent bone fractures. Therefore, we investigated the bone mass of crew members and the relationship between bone mass and lifestyle factors.
  
  
  METHODS
  We selected 1510 crew members of the Japan Maritime Self-Defense Force. All were men between 18 and 58 years of age. We measured their bone mass by applying quantitative ultrasound (QUS) to the calcaneus. In addition, we reviewed daily milk consumption, levels of physical exercise, type of on-board job, fracture history, nutritional supplementation habits, and body mass index (BMI).
  
  
  RESULTS
  Bone mass values were lower than the published mean values for Japanese men across the twenties to forties age groups.
  
  
  CONCLUSIONS
  The factors found to be related to bone mass in this study were age, type of on-board job, exercise level, and milk consumption. Lifestyle factors are usually within our control. Our data suggest that moderate levels of regular exercise and milk consumption may maintain bone mass.
authors.affiliation: Department of Orthopaedic Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
authors.forename: Toyokazu
authors.initials: T
authors.lastname: Tsuchihara
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yanagida
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsukazaki
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Okabayashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Nemoto
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000175:diagnosis / Q000209:etiology*; D002111:Calcaneus / Q000000981:diagnostic imaging*; D003611:Dairy Products; D004034:Diet Surveys; D015444:Exercise; D005247:Feeding Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D012767:Ships; D014463:Ultrasonography; D055815:Young Adult