Table 3

Adjusted mean changea [(95% confidence interval (CI)] in urinary excretion of 8-hydroxydeoxyguanosine (8-OHdG; ng/mg creatinine) by tea group and glutathione S-transferase genotypes compared with water

Urinary 8-OHdG (ng/mg creatinine)
Black teaGreen tea
Mean change(95% CI)PMean change(95% CI)P
Total population2.0(−4.1; 3.6)0.882−1.8(−8.0;−2.0)0.001
GSTM1 wild2.1(−7.7; 6.8)0.897−2.4(−10.1;−1.9)0.006
GSTM1 null2.8(−5.8; 6.1)0.957−2.6(−10.8; 0.5)0.070
GSTT1 wild3.6(−3.7; 5.2)0.739−1.9(−8.5;−1.7)0.004
GSTT1 null0.2(−9.0; 9.2)0.9831.0(−15.0; 13.6)0.909
  • a Linear regression analysis of urinary 8-OHdG as a function of treatment group, baseline measurement, body mass index, percent body fat, amount of beverage consumed, physical activity, and cohort effect.