title: Increased longevity in older users of postmenopausal estrogen therapy: the Leisure World Cohort Study.
abstract: OBJECTIVE
  To examine the effect of postmenopausal estrogen therapy (ET), including duration and recency of use, on all-cause mortality in older women.
  
  
  METHODS
  As part of a prospective cohort study of residents of a California retirement community begun in the early 1980s, Leisure World Cohort women (median age, 73 y) completed a postal health survey including details on ET use and were followed up for 22 years (1981-2003). Age- and multivariate-adjusted risk ratios (RR) and 95% CIs were calculated using proportional hazard regression.
  
  
  RESULTS
  Of the 8,801 women, 6,626 died during follow-up (median age, 88 y). ET users had an age-adjusted mortality rate of 52.9 per 1,000 person-years compared with 56.5 among lifetime nonusers (RR = 0.91; 95% CI, 0.87-0.96). Risk of death decreased with both increasing duration of ET and decreasing years since last use (P for trend <0.001). The risk was lowest among long-term (> or =15 y) users (RR = 0.83; 95% CI, 0.74-0.93 for 15-19 y and RR = 0.87; 95% CI, 0.80-0.94 for 20+ y). For long-term users, the age-adjusted mortality rate was 50.4 per 1,000 person-years. Lower-dose users (< or =0.625 mg) had a slightly better survival rate than higher-dose users (RR = 0.84; 95% CI, 0.78-0.91 vs RR = 0.91; 95% CI, 0.83-0.97). Risk did not differ by route of administration (P = 0.56). Further adjustment for potential confounders had little effect on the observed RRs for ET.
  
  
  CONCLUSIONS
  Long-term ET is associated with lower all-cause mortality in older women.
authors.affiliation: Department of Preventive Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, USA. annliahi@usc.edu
authors.forename: Annlia
authors.initials: A
authors.lastname: Paganini-Hill
authors.forename: Maria M
authors.initials: MM
authors.lastname: Corrada
authors.forename: Claudia H
authors.initials: CH
authors.lastname: Kawas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008136:Longevity / Q000187:drug effects*; D008875:Middle Aged; D009026:Mortality; D017698:Postmenopause; D011372:Progestins / Q000008:administration & dosage; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D011372:Progestins