Table 2.

Cross-sectional differences in plasma total glutathione and total cysteine according to level of cigarette consumption

	1 – 9 cigarettes/day	10 – 19 cigarettes/day	20 – 29 cigarettes/day	≥ 30 cigarettes/day	Non-smoking (quitter)
Baseline
tGSH [μM]		1.40 ± 0.62	1.54 ± 0.75	1.59 ± 1.31		P^a=0.25
Mean ± SD		1.40 ± 0.62	1.54 ± 0.75	1.59 ± 1.31		P^a=0.25
tCys [μM]		262.4 ± 95.4	265.7 ± 84.4	269.4 ± 80.0		P^a=0.82
Mean ± SD		262.4 ± 95.4	265.7 ± 84.4	269.4 ± 80.0		P^a=0.82
Follow-up
tGSH [μM]	1.47 ± 0.62	1.52 ± 0.82	1.44 ± 0.70	1.34 ± 0.42	1.91 ± 2.21	P^a=0.04
Mean ± SD	1.47 ± 0.62	1.52 ± 0.82	1.44 ± 0.70	1.34 ± 0.42	1.91 ± 2.21	P^a=0.04
tCys [μM]	217.0 ± 78.4	207.4 ± 71.9	215.9 ± 75.9	224.9 ± 66.4	221.9 ± 79.6	P^a=0.61
Mean ± SD	217.0 ± 78.4	207.4 ± 71.9	215.9 ± 75.9	224.9 ± 66.4	221.9 ± 79.6	P^a=0.61

P-value refers to differences between categories according to ANOVA