title: Cortical lens opacification in Iceland. Risk factor analysis -- Reykjavik Eye Study.
abstract: OBJECTIVE
  Cortical lens opacification has been associated with outdoor exposure and UV radiation more than other types of lens opacification. We studied risk factors for cortical lens opacification only, the most common as well as the earliest age related change we observe in the lens.
  
  
  METHODS
  1,045 persons, 583 females and 462 males, 50 years and older, underwent a detailed eye examination and answered a questionnaire. Participants with cortical lens opacification grade I, totalling 374 persons, were assigned to case-control study I, and to case-control study II those with cortical lens opacification grades II and III, totalling 82 subjects. 378 age and sex matched persons served as controls.
  
  
  RESULTS
  Those who spent more than 4 hours/day outside on weekdays, in their 20's--30's and 40's--50's respectively, were found to have increased risk of moderate to severe cortical lens opacification. Thus the relative risk for grades II & III, was 2.80 (95% CI 1.01--7.80) and 2.91 (95% CI 1.13--9.62) respectively. Ageing and systemic cortical steroids use were also found to be risk factors.
  
  
  CONCLUSIONS
  Outdoor exposure appears to be associated with increased risk of moderate to severe cortical lens opacification. Ageing is, however, the main risk factor.
authors: Department of Public Health, Juntendo University, School of Medicine, Tokyo, Japan.
authors: N
authors: N
authors: Katoh
authors: F
authors: F
authors: Jonasson
authors: H
authors: H
authors: Sasaki
authors: M
authors: M
authors: Kojima
authors: M
authors: M
authors: Ono
authors: N
authors: N
authors: Takahashi
authors: K
authors: K
authors: Sasaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D016022:Case-Control Studies; D002386:Cataract / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007904:Lens Cortex, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires