title: Emphysema, airflow limitation, and early age-related macular degeneration.
abstract: OBJECTIVE
  To describe the associations of lung function and emphysema, measured with spirometry and computed tomography (CT), with early age-related macular degeneration (AMD) in a sample of white, black, Hispanic, and Chinese subjects.
  
  
  METHODS
  Three thousand three hundred ninety-nine persons aged 45 to 84 years residing in 6 US communities participated in a period cross-sectional study. Age-related macular degeneration was measured from digital retinal photographs at the second Multi-Ethnic Study of Atherosclerosis (MESA) examination. Forced expiratory volume in 1 second (FEV(1)) and FEV(1) to forced vital capacity (FVC) ratio were measured at the third or fourth MESA examination. Percent emphysema was measured from cardiac CT scans at baseline. Apical and basilar lung segments were defined as the cephalad or caudal regions of the lung on the cardiac CT scan. Logistic regression models were used to examine the association of lung function and structure with AMD, controlling for age, sex, and other factors.
  
  
  RESULTS
  The prevalence of early AMD was 3.7%. Early AMD was not associated with FEV(1) (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.58-1.15; P = .25), FEV(1):FVC ratio (OR, 0.92; 95% CI, 0.76-1.12; P = .43), percent emphysema (OR, 1.13; 95% CI, 0.91-1.40; P = .26), and apical-basilar difference in percent emphysema (OR, 1.14; 95% CI, 0.95-1.37; P = .17). Associations were stronger in smokers. Apical-basilar difference in percent emphysema was significantly associated with early AMD among those who ever smoked (OR, 1.28; 95% CI, 1.02-1.60; P = .03). Associations were not modified by race/ethnicity.
  
  
  CONCLUSIONS
  Lung function and emphysema on CT scan were not cross-sectionally associated with AMD; this might be explained by the relatively low smoking exposure in this cohort.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 610 N Walnut St, 450 WARF, Madison, WI 53726-2397, USA. kleinr@epi.ophth.wisc.edu
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Michael D
authors.initials: MD
authors.lastname: Knudtson
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.forename: Mary Frances
authors.initials: MF
authors.lastname: Cotch
authors.forename: Graham
authors.initials: G
authors.lastname: Barr
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008268:Macular Degeneration / Q000208:ethnology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000208:ethnology / Q000503:physiopathology*; D012307:Risk Factors; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology
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