Table 5. The effect of cumulative exposure dose (CED) and metabolic enzymes genes in a multiplicative model among benzene-exposed workers.

SNPs	5.02≤CEDa≤19.90			19.90<CEDa≤31.81			31.81<CEDa≤59.00			59.00<CEDa≤364.11
	n	WBC±SD	Pb	n	WBC±SD	Pb	n	WBC±SD	Pb	n	WBC±SD	Pb
GSTM1
Present	57	6.14±1.68		56	5.75±1.58		60	5.58±1.90		42	5.46±1.31
Null	39	6.19±1.44	0.868	40	5.45±1.47	0.277	36	5.24±1.64	0.280	55	5.00±1.08	0.070
GSTT1
Present	46	6.46±1.45		53	5.78±1.71		44	5.76±2.02		45	5.24±1.32
Null	50	5.89±1.65	0.084	43	5.44±1.29	0.431	52	5.20±1.58	0.218	52	5.17±1.01	0.793
rs1695
AA	49	6.51±1.68		58	5.59±1.42		48	5.34±1.83		52	5.28±1.19
GG+AG	47	5.81±1.39	0.019	38	5.62±1.69	0.266	48	5.57±1.80	0.632	45	5.10±1.22	0.853
rs3813867
GG	70	6.31±1.71		64	5.71±1.56		62	5.55±2.02		66	5.32±1.26
CC+GC	26	5.78±1.09	0.122	32	5.46±1.49	0.620	34	5.28±1.35	0.398	31	4.93±1.04	0.093
rs2031920
CC	73	6.22±1.56		65	5.70±1.52		55	5.71±2.09		65	5.32±1.24
TT+ CT	23	6.00±1.66	0.688	31	5.48±1.57	0.608	41	5.11±1.29	0.091	32	4.94±1.10	0.070
rs6413432
TT	62	6.12±1.61		55	5.45±1.22		61	5.58±1.92		64	5.32±1.28
TA+AA	34	6.26±1.53	0.888	41	5.87±1.86	0.179	35	5.24±1.61	0.386	33	4.96±	0.335
rs1051740
TT	22	6.42±1.41		18	5.04±1.34		26	5.39±1.90		26	5.29±1.09
TC+CC	65	6.04±1.64	0.311	69	5.78±1.55	0.038	66	5.57±1.79	0.155	66	5.57±1.79	0.923
rs2234922
AA	77	5.99±1.41		71	5.61±1.49		75	5.49±1.77		68	5.29±1.12
AG+GG	19	6.87±2.01	0.055	25	5.68±1.68	0.887	21	5.37±2.00	0.932	29	4.98±1.37	0.388

SNP, single nucleotide polymorphism.

^a The exposed workers were divided into four groups with quarter cumulative exposure dose (CED).

^b P value derived from linear-regression analysis after adjusting gender, smoking, drinking, and age.