title: Low calcium intake is associated with increased bone resorption in postmenopausal Japanese women: Yokogoshi Study.
abstract: OBJECTIVE
  Low Ca intake is common among Japanese women, but its effect on bone metabolism has not been fully elucidated. The aim of the present study was to determine the relationship between Ca intake and serum markers of bone turnover in postmenopausal Japanese women.
  
  
  METHODS
  A cross-sectional study.
  
  
  METHODS
  A community setting.
  
  
  METHODS
  Subjects were 595 home-dwelling postmenopausal Japanese women. Ca intake was assessed by a validated FFQ. Serum type I collagen cross-linked N-telopeptides (NTX) and osteocalcin were measured as markers of bone turnover. The relationships between demographic characteristics, lifestyles, serum Ca, vitamin D and intact serum parathyroid hormone and bone turnover were also assessed.
  
  
  RESULTS
  The average age of the subjects was 64.5 (sd 5.8) years and the mean Ca intake was 527 (sd 160) mg/d. Ca intake was significantly associated with serum NTX (P = 0.0104), but not with serum osteocalcin. Mean serum NTX concentration in the lowest quartile of Ca intake (<417 mg/d) was significantly higher than in the fourth, referent quartile. Among these Japanese postmenopausal women, very low Ca intake (less than approximately 400 mg/d) was associated with increased bone resorption but not bone formation.
  
  
  CONCLUSIONS
  Increased bone resorption may be one mechanism by which this Ca-depleted population normalizes bone metabolism and prevents osteoporosis.
authors.affiliation: Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata City 951-8510, Japan. kazun@med.niigata-u.ac.jp
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Toshiko
authors.initials: T
authors.lastname: Saito
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshihara
authors.forename: Miki
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Rieko
authors.initials: R
authors.lastname: Oshiki
authors.forename: Ryosaku
authors.initials: R
authors.lastname: Kobayashi
authors.forename: Keiko
authors.initials: K
authors.lastname: Maruyama
authors.forename: Keiko
authors.initials: K
authors.lastname: Hyodo
authors.forename: Mitsue
authors.initials: M
authors.lastname: Nashimoto
authors.forename: Naoko
authors.initials: N
authors.lastname: Tsugawa
authors.forename: Toshio
authors.initials: T
authors.lastname: Okano
authors.forename: Mari
authors.initials: M
authors.lastname: Oyama
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D001862:Bone Resorption; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage*; D024042:Collagen Type I / Q000097:blood; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016014:Linear Models; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000097:blood; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D002136:Calcium, Dietary; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D014807:Vitamin D; D002118:Calcium