title: Age-related change in the strength of correlation of lumbar spine bone mineral density with other regions.
abstract: OBJECTIVE
  To investigate whether the strength of correlation of lumbar spine bone mineral density (BMD) with other regions differs with age.
  
  
  METHODS
  Subjects were 336 premenopausal women aged 20-49 years and 218 postmenopausal women aged 50-69 years with right-side dominance. Age, height, weight, and years since menopause (YSM) were recorded. Subjects were classified into five subgroups at 10-year increments. BMD of the arms, lumbar spine (L2-4), pelvis, legs, and total body were measured by dual-energy X-ray absorptiometry (DEXA).
  
  
  RESULTS
  Regional and total body BMD did not differ among women aged in their 20s, 30s, and 40s. However, in women aged over 50, regional and total body BMD gradually decreased with age. The strength of correlation of lumbar spine BMD with the left arm, right arm, left leg, right leg, and total body BMD gradually increased with advancing age (r=0.422-0.715, 0.376-0.714, 0.476-0.721, 0.491-0.734, and 0.642-0.800, respectively). However, the strength of correlation of lumbar spine BMD with pelvis BMD remained unchanged (r=0.512-0.622).
  
  
  CONCLUSIONS
  Correlation of lumbar spine BMD with extremities BMD gradually strengthens with advancing age, while higher correlation of lumbar spine BMD with pelvis BMD remains unchanged. When lumbar spine BMD is predicted using values at sites such as forearm BMD, we should consider the patient's age.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan. tomy@m3.kufm.kagoshima-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Douchi
authors.forename: Riki
authors.initials: R
authors.lastname: Kuwahata
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuo
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kuwahata
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Oki
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakae
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nagata
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology*; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology*; D017697:Premenopause / Q000502:physiology*