Current and past smokers appear to have a higher risk of developing late age-related macular degeneration than those who have never smoked.
Age-related macular degeneration ( AMD ) is the leading cause of blindness in the Western world.
In addition to smoking, AMD is postulated to share other risk factors with cardiovascular disease, such as elevated cholesterol level and hypertension. Smoking may also interact with AMD gene susceptibility and other environmental risk factors.
Jennifer S. L. Tan, University of Sydney and Westmead Hospital, Sydney, Australia, and colleagues examined 2,454 Australians age 49 and older to study the association between smoking and the 10-year incidence of age-related macular degeneration, as well as the possible links between smoking and other common risk factors.
The participants answered a food frequency questionnaire and had retinal photos taken at five-year and 10-year follow-up exams. An interviewer-administered questionnaire assessed participants smoking status. BMI ( body mass index ) and blood pressure were also measured.
Current smokers were found to be four times more likely to develop age-related macular degeneration and past smokers were three times as likely to have geographic atrophy, an advanced form of the disease, than those who had never smoked.
Joint exposure to current smoking and the lowest level of high-density lipoprotein ( HDL ) cholesterol, the highest total to HDL cholesterol ratio, or low fish consumption was associated with a higher risk of late age-related macular degeneration than the effect of any risk factor alone.
However, interactions between smoking and HDL cholesterol level, ratio of total to HDL cholesterol and fish consumption were not statistically significant, the authors write.
In summary, the findings from this large population-based prospective study add evidence to a possible causal relationship between smoking and the long-term risk of late, but not early, age-related macular degeneration the authors conclude. This supports speculation that age-related macular degeneration is a condition with multiple etiologic factors, and such joint effects contributing to the pathogenesis of AMD could mirror the pathogenesis of cardiovascular disease.
Source: Archives of Ophthalmology, 2007