Table 5. HRs and 95% CIs of the incidence of BTC and IHBDC according to smoking and alcohol consumption in women.
| Cases | IR per 100,000 | HRa | 95% CI | ||
| Lower | Upper | ||||
| Smoking | |||||
| IHBDC | |||||
| Never smoker | 57 | 6.0 | 1.00 | ||
| Former/Current smoker | 3 | 4.1 | 0.99 | 0.30 | 3.20 |
| BTC | |||||
| Never smoker | 213 | 22.5 | 1.00 | ||
| Former/Current smoker | 14 | 19.0 | 1.16 | 0.67 | 2.01 |
| Subtypes of BTC | |||||
| GBC | |||||
| Never smoker | 111 | 11.7 | 1.00 | ||
| Former/Current smoker | 8 | 10.9 | 1.30 | 0.62 | 2.70 |
| EHBDC | |||||
| Never smoker | 72 | 7.6 | 1.00 | ||
| Former/Current smoker | 6 | 8.1 | 1.46 | 0.62 | 3.44 |
| Alcohol | |||||
| IHBDC | |||||
| Non/Occasional drinker | 56 | 6.3 | 1.00 | ||
| Regular drinker | 2 | 1.6 | 0.43 | 0.10 | 1.79 |
| BTC | |||||
| Non/Occasional drinker | 206 | 23.2 | 1.00 | ||
| Regular drinker | 20 | 15.8 | 1.02 | 0.63 | 1.63 |
| Subtypes of BTC | |||||
| GBC | |||||
| Non/Occasional drinker | 111 | 12.5 | 1.00 | ||
| Regular drinker | 8 | 6.3 | 0.70 | 0.34 | 1.46 |
| EHBDC | |||||
| Non/Occasional drinker | 69 | 7.8 | 1.00 | ||
| Regular drinker | 9 | 7.1 | 1.34 | 0.65 | 2.76 |
BTC, biliary tract cancer; CI, confidence interval; EHBDC, extrahepatic bile duct cancer; GBC, gallbladder cancer; HR, hazard ratio; IHBDC, intrahepatic bile duct cancer; IR, incidence ratio.
aAdjusted for age, study area, body mass index, history of cholelithiasis, history of diabetes mellitus, history of chronic hepatitis or cirrhosis, Japanese tea consumption, smoking (not applicable to the analysis for smoking) and alcohol consumption (not applicable to the analysis for alcohol).