Table 1

Distribution of selected host characteristics by case–control status in Chinese
Variables Case (n = 384) Control (n = 384) Pb
Age, y (mean ± SD) 62.4 ± 10.8 61.5 ± 12.1 0.277
Gender, no. (%)
   Male 222 (57.8) 217 (56.5) 0.715
   Female 162 (42.2) 167 (43.5)
Smoking status, no. (%)
   No 228 (59.4) 218 (56.8) 0.465
   Yes 156 (40.6) 166 (43.2)
Pack-years (mean ± SD)a 32.7 ± 25.1 30.3 ± 27.7 0.209
Drinking status, no. (%)
   No 288 (75.0) 273 (71.1) 0.222
   Yes 96 (25.0) 111 (28.9)
WHO grade, no. (%)
   WHO I 41 (10.7)
   WHO II 176 (45.8)
   WHO III 86 (22.4)
   WHO IV 81 (21.1)

aAmong ever smokers.

bP values were derived from the χ2 test for categorical variables (gender, smoking and drinking status) and t test for continuous variables (age and pack-years).

Zhao et al.

Zhao et al. BMC Cancer 2013 13:234   doi:10.1186/1471-2407-13-234

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