Abstract
Purpose: :
Most epidemiologic studies of age-related macular degeneration (AMD) and its risk factors have focused on older adult populations. This cross-sectional study measured the prevalence of AMD and evaluated risk factor associations in a younger cohort.
Methods: :
Adult offspring (ages 21-84 yrs) of participants in the population-based Beaver Dam Studies were eligible for the Beaver Dam Offspring Study (BOSS), a cohort study of familial and birth cohort effects on the aging senses (n=3285, participation=66%). Digital fundus images were taken through dilated pupils and graded using standardized protocols (n=2810). AMD was defined as the presence, in either eye, of soft drusen, retinal pigment epithelial (RPE) depigmentation or increased retinal pigment, exudative macular degeneration (RPE detachment and/or increased detachment of the neurosensory retina, hemorrhage or subretinal fibrosis), or geographic atrophy. History of cigarette smoking and other lifestyle factors was obtained by questionnaire. Hearing impairment (HI) was defined as a pure-tone average 0.5,1,2,4 kHz >25 db HL.
Results: :
The prevalence of AMD was 3.4% (mean age= 49 yrs). There were 21 cases among participants less than 45 yrs of age. In a multivariate model, age (Odds Ratio (OR) = 1.24, 95% Confidence Interval (CI) = 1.11,1.39; per 5 yrs), sex (OR=1.74, 95%CI=1.05,2.87; M vs. F), HDL (OR=0.90, 95%CI= 0.82,0.99; per 5 mg/dl), pack-years (OR=1.72, 95%CI=1.04,2.85 12+ vs. 0) and HI (OR= 2.17, 95%CI= 1.32,3.55) were significantly associated with AMD.
Conclusions: :
The prevalence of AMD was low in this young cohort, but the presence in younger adults suggests that the risk for AMD may begin early in adulthood. Male gender, cigarette smoking and lower HDL were associated with AMD. These results support a link between cardiovascular risk factors and AMD. Similarly, the HI association may reflect shared vascular and/or inflammatory pathways.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: prevalence/incidence • clinical (human) or epidemiologic studies: risk factor assessment