Current Smoking Linked to Age-Related Macular Degeneration

Laurie Barclay
January 16, 2008 — Current smoking was linked with an approximately 45% higher odds of developing age-related macular degeneration (AMD) vs never smoking, according to the results of the Beaver Dam Eye Study reported in the January issue of the Archives of Ophthalmology.
"Smoking affects risk factors hypothesized to be involved in the pathogenesis of AMD, eg, immune activation, depression of antioxidant levels, reduction of choroidal blood flow, decrease in luteal pigments in retina, reduction of drug detoxification by the retinal pigment epithelium (RPE), and nicotine potentiation of angiogenic activities," write Ronald Klein, MD, MPH, from the University of Wisconsin School of Medicine and Public Health in Madison, and colleagues. "The purpose of this article is to describe the association between baseline smoking status, age at initiation, duration, intensity, pack-years, age at quitting, and time from the baseline examination since quitting and the 15-year cumulative incidence and progression of AMD in the population-based Beaver Dam Eye Study."
In this population-based, longitudinal cohort study, 4926 people in Beaver Dam, Wisconsin, who were aged 43 to 84 years in 1987 and 1988, were examined between 1988 and 1990 and again at 5-year intervals for 15 years. Stereoscopic color fundus photographs were graded for AMD status.
After adjustment for age, sex, and baseline severity of AMD, people who were current smokers at baseline were at increased risk for incident early AMD during a 15-year follow-up vs those who never smoked (odds ratio [OR], 1.47; 95% confidence interval [CI], 1.08 - 1.99; P = .01). Current smokers were also at increased risk for progression of AMD (OR, 1.43; 95% CI, 1.05 - 1.94;P = .02).
Characteristics of smoking, such as intensity, pack-years smoked, duration, and age at initiation and quitting were not specifically associated with AMD outcomes. There was no apparent association between smoking status and incident signs of late AMD. Exposure to environmental tobacco smoke in nonsmoking individuals was not associated with the 5-year incidence of early AMD or progression of AMD.
Limitations of the study include small numbers of either exudative AMD or geographic atrophy, causing an inability to rule out the possibility of an association with smoking status; and limited power to observe a relationship between smoking and incidence of late AMD in people aged 65 years or older.
"Smoking appears to be related to the long-term incidence and progression of AMD," the study authors write. "This has important health care implications because early AMD increases the risk of developing late AMD and smoking behavior is modifiable."
The National Eye Institute, the National Institute of Aging, and Research to Prevent Blindness supported this study. The study authors have obtained funding.
Arch Ophthalmol. 2008;126:115-121.