title: Epidemiology of lumbar osteoporosis and osteoarthritis and their causal relationship--is osteoarthritis a predictor for osteoporosis or vice versa?: the Miyama study.
abstract: CONCLUSIONS
  In a 10-year follow-up of a population-based cohort of Japanese subjects, incidences of and causal relationships between osteoporosis (OP) and osteoarthritis (OA) at the lumbar spine were clarified. OP might reduce the risk of subsequent OA at the spine in women, but not in men.
  
  
  BACKGROUND
  The aim of this study is to clarify the contribution of osteoarthritis (OA) to osteoporosis (OP) and vice versa.
  
  
  METHODS
  A population-based, epidemiological study was conducted in a Japanese rural community. From 1,543 participants aged 40-79 years, 200 men and 200 women were selected and followed up for 10 years. Bone mineral density measurements were repeated after 3, 7, and 10 years, and X-rays were repeated after 10 years.
  
  
  RESULTS
  The incidence of lumbar OP per 10,000 person-years for persons in their 40s, 50s, 60s, and 70s was 0, 0, 109.5, and 151.1 for men and 124.2, 384.0, 227.3, and 239.5 for women, respectively. The cumulative incidence of lumbar OA over 10 years aged 40-79 years was 25.8% in men and 45.2% in women. Cox's proportional hazards model showed no significant relationship between the presence of lumbar OA at the baseline and incidence of lumbar and femoral neck OP in both genders. A significant relationship was demonstrated between the presence of lumbar OP, not femoral neck OP, at the baseline and cumulative incidence of lumbar OA in women (odds ratio, 0.20; 95% confidence interval, 0.05-0.80; P = 0.02).
  
  
  CONCLUSIONS
  OP in women appears to reduce the future incidence of OA at the lumbar spine.
authors.affiliation: Department of Joint Disease Research, 22nd Century Medical and Research Center, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. YOSHIMURAN-ORT@h.u-tokyo.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Yoshimura
authors.forename: S
authors.initials: S
authors.lastname: Muraki
authors.forename: H
authors.initials: H
authors.lastname: Oka
authors.forename: A
authors.initials: A
authors.lastname: Mabuchi
authors.forename: H
authors.initials: H
authors.lastname: Kinoshita
authors.forename: M
authors.initials: M
authors.lastname: Yosihda
authors.forename: H
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Akune
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D010024:Osteoporosis / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D012307:Risk Factors; D016103:Spinal Fractures / Q000453:epidemiology*; D011795:Surveys and Questionnaires