Studies for the anti-oxidative marker showed levels of thiols were 1.63 ± 0.45, 1.55 ± 0.47, 1.48 ± 0.45 in the three individual APOE4 groups of the AD cohort, and 1.71 ± 0.40, 1.71 ±0.38, 1.71 ± 0.39 in the individual APOE4 groups of the non-AD cohort. The gene discussed is APOE; the disease is Alzheimer disease.