A study, examining gene-environment interactions involving both pesticides and protective factors (cigarette smoking, caffeine, and nonsteroidal anti-inflammatory drugs), found significant interactions between pesticides exposure and the NOS1 SNPs rs12829185, rs1047735, and rs2682826 in determining the risk of PD (range of p = 0.012–0.034). This evidence concerns the gene NOS1 and Parkinson disease.