title: Risk factors for nuclear lens opacification: the Reykjavik Eye Study.
abstract: OBJECTIVE
  The purpose of this study is to examine risk factors for nuclear lens opacification in citizens of Reykjavik.
  
  
  METHODS
  1,045 persons, 583 females and 462 males aged 50 years and older, were randomly sampled and underwent a detailed eye examination and answered a questionnaire. In all Scheimpflug photography of the anterior eye segment was done including the lens as well as retroilluminated photography of the lens. These photographs were used for the diagnosis of lens opacification. The data was analyzed using a logistic regression model.
  
  
  RESULTS
  An increased risk for all grades of nuclear opacifications was found with ageing (OR = 1.228, 95% CI = 1.192-1.264, p = 0.000), cigarette smoking for more than 20 pack/years (OR = 2.521, 95% CI = 1.521-4.125, p = 0.000) and pipe or cigar smoking (OR = 2.478, 95% CI = 1.200-5.116, p = 0.014). Outdoor exposure, cortical lens opacification grade II and III and computer usage were not found to be linked to higher risk of nuclear opacification. No correlation was found between nuclear opacification and the consumption of vitamins, herring, sardines and shrimps, cod-liver oil or plant oil, nor were iris color, hyperopia, systemic steroid use, cardiovascular disease, diabetes, glaucoma and pseudoexfoliation found to have a significant effect.
  
  
  CONCLUSIONS
  Ageing is a major risk factor for nuclear lens opacification, and smoking is a major modifiable risk factor. Cortical and nuclear lens opacifications do not share the same modifiable risk factors.
authors.affiliation: Department of Ophthalmology, University Hospital, Reykjavik, Iceland.
authors.forename: Arsaell
authors.initials: A
authors.lastname: Arnarsson
authors.forename: Fridbert
authors.initials: F
authors.lastname: Jonasson
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki
authors.forename: Masaji
authors.initials: M
authors.lastname: Ono
authors.forename: Vesteinn
authors.initials: V
authors.lastname: Jonsson
authors.forename: Masami
authors.initials: M
authors.lastname: Kojima
authors.forename: Nobuyo
authors.initials: N
authors.lastname: Katoh
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Sasaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002386:Cataract / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010781:Photography; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires