ABCA4 and age-related macular degeneration: Univariate analyses showed that severe AMD was related to older age (OR, 1.26; 95% CI, 1.13–1.40; p < 0.0001) and to higher RBP4 levels (OR, 1.12; 95% CI, 1.04–1.20; p = 0.003), whereas the linked ABCA4 variants had no associations.