Table 2

HR and 95% CI for alcohol intake and cigarette smoking at baseline in relation to risk of developing active tuberculosis, the Singapore Chinese Health Study 1993–2014

CasesPerson-yearsHR (95% CI)*
Alcohol intake
 Non-drinkers944824 2651.00
 Monthly to weekly208156 8710.83 (0.71 to 0.97)
 1 drink/day3013 9961.06 (0.73 to 1.53)
 2+ drinks/day6717 5581.45 (1.11 to 1.90)
Smoking status
 Never smokers534741 5381.00
 Former smokers17598 2901.08 (0.89 to 1.30)
 Current smokers540172 8612.07 (1.80 to 2.39)
Years of cigarette smoking among current smokers
 Never smokers534741 5381.00
 ≤19 years1699511.76 (1.06 to 2.90)
 20–39 years252100 3352.02 (1.70 to 2.40)
 40+ years27262 5762.11 (1.77 to 2.51)
 p Value for trend†<0.001
Number of cigarettes/day among current smokers
 Never smokers534741 5381.00
 ≤65527 4511.57 (1.18 to 2.09)
 7–1213244 9311.97 (1.61 to 2.42)
 13–2223670 3872.19 (1.84 to 2.61)
 23–326016 1072.22 (1.67 to 2.95)
 33–423898062.46 (1.75 to 3.48)
 43+1941792.79 (1.74 to 4.48)
 p Value for trend†<0.001
Years of smoking cessation among former smokers
 Never smokers534741 5381.00
 10+ years9353 8511.04 (0.82 to 1.31)
 3–9 years5428 0021.17 (0.88 to 1.56)
 ≤2 years1991401.24 (0.77 to 2.00)
 Current smokers540172 8612.07 (1.80 to 2.38)
 p Value for trend†<0.001
  • *Adjusted for age at recruitment (years), year of baseline interview (1993–1995, 1996–1998), gender, dialect group (Hokkien, Cantonese), level of education (no formal education, primary school, secondary school or higher), body mass index (kg/m2), total energy intake (kcal/day), baseline history of diabetes (yes, no), tea intake (none, monthly, weekly, daily), energy-adjusted daily intake of protein, cholesterol, marine omega-3, omega-6 fatty acids, vitamin A and vitamin C (quartiles), alcohol intake (none, monthly, weekly, daily 1 drink/day, daily 2+ drinks/day) and smoking status (never, former, current).

  • †p for linear trend tested by treating factor as continuous variable.