Plasma XOR activity [odds ratios (OR): 6.554, 95% confidence interval (CI): 1.812–23.706, p = 0.004], but not uric acid level [OR: 1.080, 95% CI: 0.718–1.626, p = 0.712], was significantly and positively associated with hypertension. The gene discussed is XDH; the disease is Hypertension.