title: Incidence of age-related cataract over a 15-year interval the Beaver Dam Eye Study.
abstract: OBJECTIVE
  To describe the long-term incidence of nuclear cataract, cortical cataract, and posterior subcapsular cataract (PSC) and to evaluate age and cohort effects on these rates.
  
  
  METHODS
  Population-based study.
  
  
  METHODS
  Members of the Beaver Dam Eye Study cohort.
  
  
  METHODS
  Subjects were seen in study offices for examinations (slit lamp, checking for occludable angles, dilation of pupils, lens photographs, measurement of blood pressures, and study interview).
  
  
  METHODS
  Lens photographs were taken with specially modified cameras that have been maintained over the course of all study examinations. Photographs were graded according to standard protocols that have been continued throughout all the examinations.
  
  
  RESULTS
  Cumulative incidence of nuclear cataract was 29.7% (95% confidence interval [CI], 28.0-31.4); cortical cataract, 22.9% (95% CI, 21.3-24.5); PSC, 8.4% (95% CI, 7.4-9.4); and cataract surgery, 17.7% (95% CI, 16.4-19.0). The cumulative incidence increased with age and was greater for women after accounting for competing events. The relationship between age and incidence of cataracts was quadratic for nuclear cataract, cubic for cortical cataract, and linear for PSC. For persons with similar ages at time of examination, those in more recent birth cohorts were less likely to have any type of prevalent cataract; the effect was significant for nuclear cataract and for cataract surgery, and the effect persisted after controlling for relevant confounders. There were apparent cohort effects on cataract incidence.
  
  
  CONCLUSIONS
  Age-adjusted incidence of all cataract types increased with increasing age, although the age effect was not linear for all 3 types. More recent birth cohorts are relatively protected relative to persons born earlier. Further follow-up is needed to verify the trends we report here and to determine whether cohort effects on 10-year incidence are significant.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA. kleinb@epi.ophth.wisc.edu
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Lee
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gangnon
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002386:Cataract / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D002387:Cataract Extraction / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D007908:Lens, Crystalline / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010781:Photography; D017678:Sex Distribution; D014922:Wisconsin / Q000453:epidemiology