Stratified analyses of population-based association showed association of elevated bladder cancer risk with GSTM1/ GSTT1 double-null in HB studies (OR=1.73, 95%CI=1.45-2.23) and PB studies (OR=2.28, 95%CI=1.22-4.25). The gene discussed is GSTM1; the disease is urinary bladder cancer.