Table 3. Comparisons of the expression levels of Bcl-2, Caspase-3 and Caspase-8 in the exposed group.

Group	Case group	Control group	χ2/t	P
Bcl-2	0.291 ± 0.044	0.211 ± 0.038	17.850	< 0.001
Caspase-3	0.338 ± 0.050	0.267 ± 0.040	14.140	< 0.001
Caspase-8	0.237 ± 0.041	0.219 ± 0.034	3.137	0.002

Note: these results were not influenced following the adjustment for cofounders such as age, smoking history and other baseline factors.