Mar 30 2009
Smoking Can Contribute to Age-Related Macular Degeneration
Long-term heavy smokers have a 2.5 to 3.5 times greater risk of losing vision from age-related macular degeneration, according to medical geneticist John R.W. Yates, Ph.D., of the University of Cambridge.
A study in the British Journal of Ophthalmology shows a strong link between smoking and age-related macular degeneration. The study also shows the risks associated with exposure to second-hand smoke.
Researchers conducted a case-control study in four British counties to determine the relationship between smoking and either of the two forms of end-stage age-related macular degeneration — geographic atrophy and choroidal neovascularization.
Between 2001 and 2003, 435 participants with age-related macular degeneration were compared with 280 controls. Of the 435 cases, 261 had choroidal neovascularization, 106 had geographical atrophy, and 68 had a mixed phenotype. Smoking status was assessed by a questionnaire; smokers were defined as those who smoked at least one cigarette a day for a year.
Scientists found a statistically significant association between age-related macular degeneration and pack-years of smoking. Pack-years were defined as the number of packs smoked a day multiplied by the number of years smoked.
Specifically, for 40 or more pack-years:
- The risk was almost triple, compared with non-smokers, for age-related macular degeneration
- For choroidal neovascularization, the risk was more than double
- For geographic atrophy, the risk was more than triple.
Compared with non-smokers who weren’t exposed to second-hand smoke, the non-smokers who had such exposure had nearly twice the risk of having any form of age-related macular degeneration.
Learn more about macular degeneration including recommended self-help and nutrition to reduce your risk of blindness
Source: “Smoking and age related macular degeneration: the number of pack years of cigarette smoking is a major determinant of risk for both geographic atrophy and choroidal neovascularization,” Khan, et al, Br J Ophthalmol 2006;90:75-80.
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