Smoking and hepato-biliary disease.

The effect of cigarette smoking has been assessed in several hepato-biliary diseases, although in only a few was smoking the main focus of the study. Other than in primary sclerosing cholangitis, the relationships found are not strong and it remains unclear whether any are causal in nature - particularly in the absence of clearly demonstrated biological mechanisms. Nevertheless, many studies have found a modest but definite association between smoking and gallstone disease. As smoking is so prevalent in many countries, the public health impact of even a weak causal relationship would be considerable.