Table 4.

Stratified analyses of NAT1 polymorphisms on cancer risk by source of control

Variables	N	OR	95% CIs	Tau-squared	I2 (%)	P for Heterogeneity
Total	76	0.978	0.927-1.030	0.0215	45.5	< 0.001
PB
Lung cancer	1	0.695	0.474-1.020	0.1279	_	_
Colorectal cancer	10	1.063	0.929-1.217	0.0225	65.0	0.002
Non-Hodgkin’s lymph	4	1.020	0.899-1.157		0	0.846
Bladder cancer	2	1.022	0.792-1.318	0.0265	0	0.587
Prostate cancer	6	1.035	0.923-1.161	0	0	0.818
Gastric cancer	1	1.385	0.853-2.249	0.2425	_	_
Breast cancer	3	0.896	0.717-1.118	0	0	0.832
other cancers	1	0.834	0.476-1.459	_	_	_
HB
Lung cancer	4	0.911	0.564-1.471	0.0074	76.7	0.005
Colorectal cancer	13	0.882	0.798- 0.974	0.0334	22.9	0.212
Head and neck cancer	5	0.826	0.595-1.146	0.0836	63.5	0.027
Pancreatic cancer	3	0.856	0.733-0.999	0	0	0.509
Non-Hodgkin’s lymph	1	0.874	0.575-1.328	0	_	_
Bladder cancer	10	1.075	0.911-1.269	0.0152	55.9	0.015
Prostate cancer	2	0.784	0.483-1.272	0	76.4	0.040
Gastric cancer	3	0.786	0.379-1.629		85.9	0.001
Breast cancer	2	1.044	0.835-1.306		0	0.517
other cancers	5	1.146	0.930-1.411		0	0.641

N: involved studies’ number; OR, odds ratio; PB: population-based case control study; HB: hospital-based case control. Random model was chosen for data pooling when P-value < 0.10 and /or I² > 50%; otherwise fixed model was used; The numbers in bold indicated statistically significant values.