Table 1.

Baseline demographic and lifestyle characteristics of current smokers who developed lung cancer (cases) and those who remained cancer-free (controls) in the Shanghai Cohort Study and the Singapore Chinese Health Study

Shanghai CohortSingapore Cohort
CasesControlsP *CasesControlsP *
Total no. subjects1551529193
Age at interview (y), mean (SD)57.9 (4.8)57.6 (4.7)0.6161.1 (6.5)61.3 (6.4)0.83
Sex, n (%)
    Males155 (100)152 (100)80 (87.9)81 (87.1)0.87
    Females0 (0)0 (0)11 (12.1)12 (12.9)
Body mass index (kg/m2), mean (SD)21.5 (2.8)21.8 (3.0)0.3421.6 (2.8)22.0 (2.6)0.23
Level of education, n (%)
    No formal education18 (11.6)8 (5.3)0.1228 (30.8)24 (25.8)0.61
    Primary school61 (39.4)60 (39.5)53 (58.2)55 (59.1)
    Secondary school76 (49.0)84 (55.2)10 (11.0)14 (15.1)
No. cigarettes per day, mean (SD)20.7 (7.7)15.3 (7.2)<0.000119.5 (12.2)18.2 (14.4)0.50
No. years of smoking, mean (SD)36.7 (8.2)33.6 (9.1)0.00248.2 (10.0)46.6 (10.7)0.29
No. pack-years of smoking, mean (SD)38.4 (16.7)26.0 (14.4)<0.000147.1 (32.0)43.2 (33.8)0.42
Urinary cotinine (ng/mg creatinine), mean (SD)3,033 (2,244)1,972 (1,573)<0.00012,873 (1,758)2,517 (1,825)0.18
Alcohol drinking, n (%)
    Nondrinkers69 (44.5)65 (42.8)0.7650 (55.0)64 (68.8)0.05
    Regular drinkers86 (55.5)87 (57.2)41 (45.0)29 (31.2)
    No. alcoholic drinks per day, mean (SD) 3.7 (3.2)2.4 (1.8)0.0021.4 (2.2)1.0 (1.5)0.32
  • * P values (two-sided) were derived from t test (for means) or χ2 (for frequencies) statistics.

  • Among alcohol drinkers only.