Cigarette smoking and primary liver cancer: a population-based case-control study in US men

Using the case-control data from the Selected Cancers Study, the authors assessed whether cigarette smoking increases the risk of primary liver cancer in the US.

Cases were men who were pathologically diagnosed with primary liver cancer during 1984-1988, were 31-59 years old, and lived in the areas covered by eight US cancer registries (n=168). Controls were men without a history of primary liver cancer who were selected by random-digit telephone dialing (n=1910).

Relative to non-smokers, the risks of liver cancer were 1.85 (95% confidence interval (CI), 1.05-3.25) and 1.49 (95% CI, 0.83-2.68) for former and current smokers, respectively. The adjusted odds ratio (OR) estimates were 0.96, 1.43, 1.80, and 1.87 for smoking for less than 15, 15-24, 25-34 and 35 or more years, respectively (p for trend=0.039). The OR estimates were 1.41 (95% CI, 0.74-2.68), 1.67 (95% CI, 0.93-2.98), and 1.83 (95% CI, 0.89-3.76) for less than 1, 1-2, and 2 or more packs smoked per day (p for trend=0.068).

Cigarette smoking may be a factor that contributes somewhat to the occurrence of primary liver cancer among men in the United States, a country with low risk of liver cancer.