Risk of death due to hepatocellular carcinoma among smokers and ex-smokers. Univariate analysis of JACC study data.

Hazard ratios (HR) of death due to hepatocellular carcinoma (HCC) were analyzed by gender and age strata (40-59 and 60-79) among smokers and ex-smokers in 65,528 eligible subjects from a large cohort of males and females aged 40-79 years, based on information about several smoking-related characteristics. Both current smokers and ex-smokers among total older males had hazard ratios (HR) for dying from HCC that were 2 to 4 times higher than those who had never smoked at the baseline survey. When subjects were restricted to those without history of liver disease (LD), older male (60-79) ex-smokers presented a statistically significant HR of 5.0. Earlier age at start of smoking (15 to 19) showed a significantly increased HR of 4 to 8 for both current and ex-smokers. Moderate number of cigarettes smoked per day showed an increased HR, and later age at cessation of smoking had a higher HR compared to earlier cessation. Larger cumulative amount of smoking resulted in an elevated HR of 11 times than in those who had never smoked. Cigarette smoking was suggested to be an important risk factor for death from HCC regardless of whether the smoking habit was in the past or was continuing at present. To eliminate confounding effects and interaction with other risk factors of HCC and to clarify the net association between smoking habits and HCC, farther careful analysis using multivariate models is needed.