Nongenetic risk factors for neovascular age-related macular degeneration

To create a risk model for neovascular age-related macular degeneration (nAMD) based on nongenetic factors.

In this case-control study, 1459 individuals were included, 445 patients showed nAMD and 1014 were healthy controls. Participants were randomly assigned into a training set (containing two-thirds of individuals) and a validation set. Stepwise logistic regression analysis was performed for 25 environmental risk factors in the training set. The risk model with the remaining factors was then validated in the validation set using receiver operating characteristics (ROC) curve and Hosmer-Lemeshow-Test. Additionally, a genetic risk model including variants in the complement factor H gene (CFH, rs1061170) and the age-related maculopathy susceptibility 2 gene (ARMS2, rs10490924) was generated.

The environmental risk model with the factors age, alcohol use, allergy, education, sunlight exposure, fish consumption, and physical exercise showed an AUC of 0.80 (95% confidence interval [CI] 0.76-0.84) in the training set. Validation of the model showed adequate calibration (Hosmer-Lemeshow P = 0.81). The AUC for the genetic model was 0.77 (95% CI 0.730-0.808), for the combined environmental and genetic model 0.92 (95% CI 0.887-0.947).

Seven nongenetic factors are able to provide equivalent discrimination between nAMD patients and controls to genetic risk models. Most of them are modifiable and give the opportunity for counseling patients.