title: [Risk factors for lens opacification in Icelanders 50 years and older. Reykjavík Eye Study.].
abstract: OBJECTIVE
  To examine risk factors for cortical and nuclear lens opacification in older citizens of Reykjavík.
  
  
  METHODS
  1045 persons, 583 females and 462 males age 50 years and older were randomly sampled and underwent detailed eye examination including slit-lamp and Scheimpflug photography of the lens and answered a questionnaire. The photographs were used for the diagnosis of lens opacification. The data was analysed using a logistic regression model.
  
  
  RESULTS
  An increased risk was found with ageing for developing both nuclear (OR=1.23: 95% CI 1.19-1.26: p<.001) and severe cortical lens opacification (OR=1.19: 95% CI 1.16-1.22: p<.001). Cigarette-smoking for more than 20 pack-years increased risk for nuclear lens opacification (OR=2.52: 95% CI 1.52-4.13: p<.001) as well as pipe- or cigar-smoking (OR=2.48: 95% CI 1.20-5.12: p<.05). Those who spent more than 4 hours/day outside on weekdays in their 20's - 30's and 40's and 50's were found to have increased risk of severe cortical lens opacification (OR=2.80: 95% CI 1.01-7.80: p<.05 and OR=2.91: 95% CI 1.13-9.62: p<.05, respectively). Systemic corticosteroid use was also found to be a significant risk factor for cortical lens opacification (OR=3.70: 95% CI 1.43-9.56: p<.05).
  
  
  CONCLUSIONS
  In our study, ageing is the main risk factor for both cortical and nuclear lens opacification. Important modifiable risk factors are smoking for nuclear lens opacification and systemic corticosteroid use and outdoor exposure for cortical lens opacification.
authors.affiliation: Department of Eye Diseases, Landspitali University Hospital, Hringbraut, 101 Reykjavík, Iceland. fridbert@landspitali.is.
authors.forename: Arsæll
authors.initials: A
authors.lastname: Arnarsson
authors.forename: Friðbert
authors.initials: F
authors.lastname: Jónasson
authors.forename: Nobuyo
authors.initials: N
authors.lastname: Katoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki
authors.forename: Vésteinn
authors.initials: V
authors.lastname: Jónsson
authors.forename: Masami
authors.initials: M
authors.lastname: Kojima
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Sasaki
authors.forename: Masaji
authors.initials: M
authors.lastname: Ono