Purpose
Higher adherence to Mediterranean-type diet is linked to lower risk for mortality and chronic disease, but the association with age-related macular degeneration (AMD) is unclear. Although specific foods have been associated with AMD, a global diet approach could also be useful to better understand the relationship between nutritional factors and AMD. We examined the association of adherence to the Mediterranean diet and genetic susceptibility with progression to advanced AMD.
Methods
We included 2552 subjects from the Age-Related Eye Disease Study (AREDS), among whom 1059 eyes progressed to advanced AMD over 13 years. Eyes without advanced AMD at baseline were evaluated for progression to advanced AMD. Data on age, gender, smoking, education, body mass index and supplement use were collected at baseline using questionnaires. Dietary data were collected from food frequency questionnaires at baseline. The alternate Mediterranean diet (A-MedDiet Score, 0-9) was constructed using intake of vegetables, fruits, legumes, whole grains, nuts, fish, red and processed meats, moderate alcohol, and the ratio of monounsaturated to saturated fats. Ten genetic loci in 7 genes (CFH, ARMS2, C2, C3, CFB, COL8A1 and RAD51B) were examined. Cox proportional hazards models using individual eyes as the unit of analysis were used to assess associations between incident AMD and A-MedDiet Score and interaction effects between A-MedDiet Score and genetic variation on risk of AMD.
Results
A higher A-MedDiet Score (6-9) was significantly associated with a reduced risk of progression to advanced AMD after adjusting for demographic and behavioral covariates, AREDS treatment and AMD at baseline, and after the inclusion of 10 genetic variants (HR=0.82, 95%CI: 0.67-1.00, p=0.05, p trend=0.048; HR=0.78, 95%CI: 0.64-0.95, p=0.01, p trend=0.016, respectively).<br /> A-MedDiet Score was significantly associated with a lower risk of incident advanced AMD among subjects with the CFH Y402H non-risk (T) allele (p trend=0.002; p interaction=0.04). A-MedDiet Score was not associated with reduced risk of advanced AMD among subjects homozygous for the risk (C) allele CFH Y402H (p trend=0.66).
Conclusions
Higher adherence to Mediterranean diet was associated with reduced risk of advanced AMD and may modify genetic susceptibility for progression to advanced AMD.