title: Osteoporosis and fractures in postmenopausal women using estrogen.
abstract: BACKGROUND
  Previous studies demonstrate that postmenopausal women who use estrogen are somewhat protected from bone loss and fractures compared with nonusers, but the extent to which estrogen users remain at risk for osteoporosis and fractures is uncertain.
  
  
  OBJECTIVE
  To determine long-term probabilities for incident fractures among postmenopausal estrogen users.
  
  
  METHODS
  We examined data from the Study of Osteoporotic Fractures, a prospective cohort study with 10 years of follow-up (1986-1999). This cohort includes 8816 women 65 years and older from community settings in 4 areas of the United States.
  
  
  METHODS
  Hip, wrist, vertebral, and nonvertebral fractures.
  
  
  RESULTS
  At baseline, using criteria developed by the World Health Organization, 40% of continuous estrogen users were osteopenic and 13% were osteoporotic at the hip or spine. Although women currently using estrogen lost less bone density than past users or those who never used estrogen, all user groups on average lost bone from the hip and calcaneus. During 10 years of observation, the adjusted probability of nonvertebral fractures was 19.6% for continuous estrogen users, similar to current partial users and lower than past users and those who never used estrogen (P<.05). These comparisons were similar for hip, wrist, and vertebral fractures.
  
  
  CONCLUSIONS
  Although estrogen use is associated with reduced prevalence of low bone density, less bone loss, and lower probabilities for fractures, osteoporosis and fractures are common in older women who used estrogen continuously since menopause. Estrogen users should be considered in strategies designed to detect, prevent, and treat osteoporosis.
authors.affiliation: Department of Medical Informatics and Outcomes Research, Oregon Health and Science University, Mailcode BICC-504, 3181 SW Sam Jackson Park Rd, Portland, OR 97201, USA. nelsonh@ohsu.edu
authors.forename: Heidi D
authors.initials: HD
authors.lastname: Nelson
authors.forename: Joanne
authors.initials: J
authors.lastname: Rizzo
authors.forename: Emily
authors.initials: E
authors.lastname: Harris
authors.forename: Jane
authors.initials: J
authors.lastname: Cauley
authors.forename: Kristine
authors.initials: K
authors.lastname: Ensrud
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Eric
authors.initials: E
authors.lastname: Orwoll
mesh_terms: D000367:Age Factors; D000368:Aged; D015519:Bone Density / Q000187:drug effects; D015331:Cohort Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D005500:Follow-Up Studies; D050723:Fractures, Bone / Q000517:prevention & control*; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control*; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors