This study found significant differences in frequencies of both genotypes of MnSOD and NQO1 polymorphisms between PD patients and the control subjects only among subjects who had been exposed to pesticide (OR = 2.49, 95% CI [1.18–5.26] for MnSOD C allele; OR = 2.42, 95% CI [1.16–4.76] for NQO1 T allele). Here, NQO1 is linked to Parkinson disease.