|| Checking for direct PDF access through Ovid
Age-related macular degeneration (AMD) is the most common cause of incurable visual impairment in high-income countries. Previous studies report inconsistent associations between AMD and apolipoprotein E (APOE), a lipid transport protein involved in low-density cholesterol modulation. Potential interaction between APOE and sex, and smoking status has been reported. We present a pooled analysis (n= 21,160) demonstrating associations between late AMD andAPOε4(odds ratio [OR] = 0.72 per haplotype; confidence interval [CI]: 0.65–0.74;P= 4.41×10−11) andAPOε2(OR = 1.83 for homozygote carriers; CI: 1.04–3.23;P= 0.04), following adjustment for age group and sex within each study and smoking status. No evidence of interaction betweenAPOEand sex or smoking was found. Ever smokers had significant increased risk relative to never smokers for both neovascular (OR = 1.54; CI: 1.38–1.72;P= 2.8×10−15) and atrophic (OR = 1.38; CI: 1.18–1.61;P= 3.37×10−5) AMD but not early AMD (OR = 0.94; CI: 0.86–1.03;P= 0.16), implicating smoking as a major contributing factor to disease progression from early signs to the visually disabling late forms. Extended haplotype analysis incorporating rs405509 did not identify additional risks beyondε2andε4haplotypes. Our expanded analysis substantially improves our understanding of the association between theAPOElocus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology. 32:1407–1416, 2011. ©2011 Wiley Periodicals, Inc.