October 01, 2009
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Nutrition, smoking and genetic factors contribute to etiology of macular degeneration

The complement factor H Y402H polymorphism was strongly associated with neovascular AMD and with early stage 2 age-related maculopathy, study shows.

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PARIS — A French epidemiological study on a large number of cases demonstrated significant correlations between age-related macular degeneration, complement factor H Y402H polymorphism, smoking and high HDL-cholesterol levels.

“The association between the [complement factor H, CFH] gene and the risk for neovascular AMD, particularly in homozygote subjects, was already established by several studies. CFH plays a role in inflammation, which was therefore proven to be an important component of the macular age-related disease,” Marie Bénedicte Renaud Rougier, MD, said at the meeting of the French Society of Ophthalmology here. “Also, advanced AMD was shown to be two to three times more frequent amongst smokers in a number of studies.”

CFH Y402H polymorphism

The French, population-based ALIENOR (Antioxydants, lipides essentiels, nutrition et maladies oculaires) study, carried out at the University of Bordeaux, confirmed these data by analyzing a cohort of 963 subjects aged 65 years or older.

The Y402H polymorphism of CFH was determined in 878 (91.2%) cases. In 796 of these subjects, eye fundus images could be analyzed and classified in five stages according to the international classification of age-related maculopathy (ARM): stage 0 for no sign of macular disease, stage 1 and 2 for ARMs, and stage 3 and 4 for AMD, geographic atrophy and neovascular AMD.

“The CFH Y402H polymorphism was strongly associated with neovascular AMD and with stage 2, early ARM. Adjustment for smoking did not modify the association, and this is important because smoking decreases the plasma concentration of CFH,” Dr. Renaud Rougier said.

Cumulative effect of smoking

Smoking was equally associated with stage 4, neovascular AMD and with early stage 2 ARM.

“There was a relatively low number of smokers (46 subjects) in this age group, and the correlation with the risk of age-related macular pathologies was major,” Dr. Renaud Rougier said. “The risk is cumulative: It increases with the number of packets per year.”

Adjustment for CFH did not modify the association.

The part of the ALIENOR study presented by Dr. Renaud Rougier confirmed the contribution of CFH and smoking to the etiology of ARM. Another part of the study analyzed the correlation between HDL-cholesterol levels and the five stages of ARM in the same cohort of patients. A positive association was found with all stages of ARM, reaching statistical significance for stages 2 and 4. – by Michela Cimberle