Evidence of association of APOE with age-related macular degeneration: a pooled analysis of 15 studies.

McKay GJ, Patterson CC, Chakravarthy U, Dasari S, Klaver CC, Vingerling JR, Ho L, de Jong PT, Fletcher AE, Young IS, Seland JH, Rahu M, Soubrane G, Tomazzoli L, Topouzis F, Vioque J, Hingorani AD, Sofat R, Dean M, Sawitzke J, Seddon JM, Peter I, Webster AR, Moore AT, Yates JR, Cipriani V, Fritsche LG, Weber BH, Keilhauer CN, Lotery AJ, Ennis S, Klein ML, Francis PJ, Stambolian D, Orlin A, Gorin MB, Weeks DE, Kuo CL, Swaroop A, Othman M, Kanda A, Chen W, Abecasis GR, Wright AF, Hayward C, Baird PN, Guymer RH, Attia J, Thakkinstian A and Silvestri G

Hum Mutat (2011) 32:1407-16

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 and APOepsilon4 (odds ratio [OR] = 0.72 per haplotype; confidence interval [CI]: 0.65-0.74; P = 4.41x10(-11) ) and APOepsilon2 (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 between APOE and 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 = 2.8x10(-15) ) and atrophic (OR = 1.38; CI: 1.18-1.61; P = 3.37x10(-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 beyond epsilon2 and epsilon4 haplotypes. Our expanded analysis substantially improves our understanding of the association between the APOE locus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology.