Table 1.

Essential information and laboratory parameters among 500 occupational workers

Variables a	low 8-OHdG (≤ 204.05 mmol/mol Cr)	high 8-OHdG (>  204.05 mmol/mol Cr)	P b
Sex
Male	217 (86.8)	228 (91.2)	0.116
Female	33 (13.2)	22 (8.8)
Age (years)	39 (32–45)	41 (37–46)	0.009
Years of working	20 (14–27)	22 (17–28)	0.007
Education (years)
< 9	53 (21.1)	66 (26.4)	0.273
9–12	92 (36.8)	94 (37.6)
> 12	105 (42.0)	90 (36.0)
Occupation
Coke oven worker	191 (76.4)	198 (79.2)	0.451
Water treatment worker	59 (23.6)	52 (20..8)
Central heating
yes	237 (94.8)	233 (93.2)	0.451
no	13 (5.2)	17 (6.8)
Smoking status
yes	94 (37.9)	132 (53.2)	0.001
no	154 (62.1)	116 (46.8)
Drinking status
yes	142 (56.8)	178 (71.2)	0.001
no	108 (43.2)	72 (28.8)
1-OHP (μg/mmol Cr)	0.05 (0.03–0.09)	0.06 (0.04–0.10)	0.144
2-NAP (μg/mmol Cr)	0.65 (0.36–1.07)	0.79 (0.44–1.25)	0.007
2-FLU (μg/mmol Cr)	0.26 (0.17–0.46)	0.28 (0.19–0.43)	0.395
9-PHE (μg/mmol Cr)	0.08 (0.06–0.14)	0.09 (0.06–0.17)	0.856
ΣPAH (μg/mmol Cr)	0.27 (0.18–0.46)	0.34 (0.23–0.48)	0.014
CYP1A1 methylation
pos.1	2.95 (0.00–4.36)	2.43 (0.00–4.07)	0.129
pos.2	2.19 (0.00–3.47)	1.83 (0.00–3.49)	0.913
pos.3	4.83 (2.24–6.17)	3.92 (0.00–6.00)	0.055
pos.4	2.40 (0.00–3.94)	2.09 (0.00–3.51)	0.477
pos.5	2.52 (0.00–4.53)	1.43 (0.00–3.99)	0.060
average	3.10 (1.63–4.20)	2.42 (1.29–3.85)	0.031

Drinking status missing 4 values

^a Data were presented as n (%) or Median (25th - 75th)

^b P-values were calculated from Chi-square test for categorical variables and Mann-Whitney U test for numerical variables