Table 2. Non-paramatric model analysis of treatment and time on concentrations of urinary 8-OHdG.

Effect	Test statistic (P-value)
Treatment	5.58 (P = 0.001)
Time	97.92 (P<0.001)
Treatment*Time	17.15 (P<0.001)
TC v.s. Placebo	10.62 (P = 0.001)
GTP v.s. Placebo	3.76 (P = 0.037)
(GTP+TC) v.s. Placebo	4.80 (P = 0.029)
TC*Time (time effect in TC group)	13.38 (P<0.001)
GTP*Time (time effect in GTP group)	67.20 (P<0.001)
(GTP+TC)*Time(time effect in (GTP+TC) group)	3.24 (P = 0.043)

The test statistics and P-values shown here were generated from a non-parametric model designed for repeated measurements using SAS macro F1_LD_F1, the more detailed information on model assumption and hypothesis is referred to reference #30, chapter 8.