GSTM1 and benign prostatic hyperplasia: Also, high risks were found between PCa and GSTM1 null genotype in population-based (OR = 1.2192, 95% CI = 1.0488–1.4172, P = 0.0099, I2 = 68.48%), hospital-based (OR = 1.5431, 95% CI = 1.1417–2.0856, P = 0.0048, I2 = 78.24%) or in BPH-based controls (OR = 1.3522, 95% CI = 1.0067–1.8163, P = 0.045, I2 = 64.6%).