title: Body mass index and age-related cataract: the Shihpai Eye Study.
abstract: OBJECTIVE
  To investigate the association between body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) and cataract in a metropolitan Asian elderly population.
  
  
  METHODS
  Population-based cross-sectional study. Age-related cataract was defined as any type of lens opacity (ie, nuclear, cortical, and posterior subcapsular opacity) with a Lens Opacities Classification System III grade of more than 2 in one or both eyes. Weight and height were measured by intensively trained interviewers.
  
  
  RESULTS
  A total of 2045 subjects 65 years and older in Shihpai, Taipei, were invited to participate, and 1361 (66.6%) completed the survey. Of the subjects, 806 were diagnosed as having age-related cataracts. With a BMI of less than 21.3 as a reference point (odds ratio [OR], 1.00), a U-shaped relationship between BMI and nuclear opacity was demonstrated. A reverse U-shaped relationship was shown for cortical opacity. In the final multiple logistic regression models, BMI and BMI(2) were significantly related to nuclear opacity (BMI data: OR, 0.73 [95% confidence interval {CI}, 0.54-0.98]; and BMI(2) data: OR, 1.01 [95% CI, 1.00-1.01]) and cortical opacity (BMI data: OR, 1.52 [95% CI, 1.04-2.34]; and BMI(2) data: OR, 0.99 [95% CI, 0.98-0.99]). Neither BMI nor BMI(2) was related to posterior subcapsular opacity.
  
  
  CONCLUSIONS
  Body mass index is an independent risk factor for nuclear and cortical opacities, but in reverse direction to each other.
authors.affiliation: Community Medicine Research Center and Institute of Public Health and Department of Ophthalmology, National Yang-Ming University, Shihpai, Taipei 211, Taiwan.
authors.forename: Tung-Mei
authors.initials: TM
authors.lastname: Kuang
authors.forename: Su-Ying
authors.initials: SY
authors.lastname: Tsai
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Hsu
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Cheng
authors.forename: Jorn-Hon
authors.initials: JH
authors.lastname: Liu
authors.forename: Pesus
authors.initials: P
authors.lastname: Chou
mesh_terms: D000368:Aged; D000375:Aging; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002386:Cataract / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology