CAT and cystic fibrosis: CAT activity was significantly lower in all CF subgroups (CFGB− = 24.20 mmol/min/ml, P = .042; CFGB+ = 19.10 mmol/min/ml, P = .010; CFGPa− = 22.68 mmol/min/ml, P = .021; CFGPa+=18.97 mmol/min/ml, P = .019) compared with CG (32.20 mmol/min/ml, Table 1), even after adjusting for confounding variables (Tables 3 and 4).