Genetic and environmental risk factors for age-related macular degeneration in persons 90 years and older

Purpose: We studied associations of genetic polymorphisms in age-related maculopathy susceptibility 2 (ARMS2) and complement factor H (CFH) in nonagenarians with age-related macular degeneration (AMD).

Methods: This case-control study comprised 2737 persons (1204 controls, 1433 AMD cases), including 166 nonagenarians (52 controls, 114 AMD cases). Single nucleotide polymorphisms (SNPs) in the genes ARMS2 and CFH were determined. Risk scores were computed by multiple logistic regression analysis, including genetic and environmental risk factors (smoking, hypertension, body mass index, diabetes) for different age groups (<70, 70-79, 80-89, ≥ 90 years [nonagenarians]).

Results: In nonagenarians, ARMS2 showed the weakest associations with AMD (odds ratio [OR] = 1.52, P = 0.127) compared to the other groups (OR, 70 years = 2.23, P = 1.03 × 10(-13); OR, 70-79 years = 2.70, P = 1.00 × 10(-13); OR, 80-89 years = 3.11, P = 6.56 × 10(-8)). For CFH, ORs for AMD increased with age (<70 years OR = 1.96, P = 1.80 × 10(-11); 70-79 years OR = 1.89, P = 4.48 × 10(-13); 80-89 years OR = 2.71, P = 1.28 × 10(-7)), but decreased again in the nonagenarians (OR = 2.21, P = 0.005). Compared to the group <70 years, reduced minor allele frequencies (MAFs) for AMD patients were observed in the nonagenarians (CFH 0.54 vs. 0.43, P = 0.009; ARMS2 0.44 vs. 0.29, P = 2.97 × 10(-5)), while the MAFs in controls were not significantly different. The genetic risk score revealed the lowest discriminative power in the nonagenarians with an area-under-curve (AUC) of 0.658 for receiver-operating characteristics (AUC 80-89 years = 0.768, 70-79 years = 0.704, <70 years = 0.682), while no significant difference was seen for the environmental risk score (AUC < 70 years = 0.579, 70-79 years = 0.567, 80-89 years = 0.600, >90 years = 0.608).

Conclusions: Risk alleles in CFH and ARMS2 have a significantly smaller effect on AMD development in nonagenarians, while environmental factors retain a similar effect.