Genetic variations in the SMAD4 gene and gastric cancer susceptibility

Table 2 Frequency distributions of selected variables between gastric cancer cases and cancer-free controls n (%)

Variables	Cases (n = 322)	Controls (n = 351)	P1
Age (yr)
< 60	129 (40.1)	153 (43.6)	0.354
≥ 60	193 (59.9)	198 (56.4)
Sex
Male	215 (66.8)	226 (64.4)	0.516
Female	107 (33.2)	125 (35.6)
Smoking status
Never	181 (56.2)	228 (65.0)	0.020
Regular	141 (43.8)	123 (35.0)
Drinking status
Never	217 (67.4)	239 (68.1)	0.846
Regular	105 (32.6)	112 (31.9)
Tumor site2
Cardia	149 (48.1)
Non-cardia	161 (51.9)
Histological types2
Intestinal	162 (52.3)
Diffuse	148 (47.7)
Depth of tumor infiltration2
T1	80 (25.8)
T2	68 (22.0)
T3	112 (36.1)
T4	50 (16.1)
Lymph node metastasis2
Negative	166 (52.9)
Positive	148 (47.1)

¹Two-sided χ² test for the frequency distribution of selected variables between gastric cancer cases and cancer-free controls;

²No. of subjects in cases (n = 310 for tumor site, n = 310 for histological types, n = 310 for depth of tumor infiltration, and n = 314 for lymph node metastasis) were less than the total number (n = 322) because some information was not obtained.