Abstract
Purpose:
To determine whether pulmonary function and respiratory disease are associated with the incidence of early and late age-related macular degeneration (AMD).
Methods:
Participants were aged 43-86 years at the Beaver Dam Eye Study (BDES) baseline examination in 1988-1990 and participated in follow-up examinations spaced 5 years apart. Current history of emphysema, asthma and respiratory symptoms was determined from self-report. Respiratory symptoms were defined by winter cough, wheezing, and coughing up phlegm. Peak expiratory flow rate (PEFR) was measured. Current history of emphysema was first measured at the baseline examination (N=2773 and N=3461 at risk for early and late AMD, respectively), current history of asthma was first measured at BDES examination phase 2 (N=2014 and N=2603 at risk for early and late AMD, respectively), and PEFR and history of respiratory symptoms were first measured at BDES examination phase 3 (N=1596 and N=2051 at risk for early and late AMD, respectively). Incidence was defined over each interval conditional upon being free of disease at all previous examinations. Relationships were analyzed using discrete-time hazard models using the complementary log-log link function, and risk factors were updated at each examination phase. AMD severity was assessed by grading of fundus photographs.
Results:
A history of respiratory symptoms was present in 42.9%, emphysema in 3.2% and asthma in 6.6% of the population. The 5-year incidence of early AMD was 8.5% and late AMD was 1.5%. While adjusting for age, sex, smoking status and other factors, a current history of respiratory symptoms was associated with the incidence of late AMD (reported as hazard ratio, 95% confidence interval, P value; mild vs. no symptoms 1.86, 1.07-3.24, P=0.02). Individuals with PEFR in the highest sex-specific quartile had a borderline decreased risk of early AMD (0.69, 0.46-1.04, P=0.07) and late AMD (0.35, 0.11-1.15, P=0.08) compared to those in the lower 3 quartiles. There was a trend of an association between a current history of emphysema and incidence of early AMD (1.30, 0.81-2.10, P=0.28). A current history of asthma was not associated with early or late AMD.
Conclusions:
Our findings suggest that respiratory symptoms and dysfunction that possibly result from smoking remain associated with the incidence of early and late AMD independent of smoking.
Keywords: 412 age-related macular degeneration •
462 clinical (human) or epidemiologic studies: outcomes/complications •
463 clinical (human) or epidemiologic studies: prevalence/incidence