Separate and Joint Effects of Alcohol and Smoking on the Risks of Cirrhosis and Gallbladder Disease in Middle-aged Women
American Journal of Epidemiology Advance Access published online on November 25, 2008


The examined were separate and joint effects of alcohol and smoking on incidences of liver cirrhosis and gallbladder disease in a prospective study of 1,290,413 United Kingdom women (mean age, 56 years) recruited during 1996–2001.

After a mean follow-up of 6.1 years (1996–2005), incidence rates of cirrhosis and gallbladder disease were 1.3 per 1,000 persons (n = 2,105) and 15 per 1,000 persons (n = 23,989), respectively, over 5 years. Cirrhosis risk increased with increasing alcohol consumption, while the risk of gallbladder disease decreased (P_trend < src="http://aje.oxfordjournals.org/math/ge.gif" alt="≥" border="0">15 units/week with those who drank 1–2 units/week, the relative risk was 4.32 (95% confidence interval (CI): 3.71, 5.03)) for cirrhosis and 0.59 (95% CI: 0.55, 0.64) for gallbladder disease.

Increasing numbers of cigarettes smoked daily increased the risk of both conditions (P_trend <> current smokers of 20 cigarettes/day with never smokers, the relative risk was 3.76 (95% CI: 3.25, 4.34) for cirrhosis and 1.29 (95% CI: 1.22, 1.37) for gallbladder disease.

Effects of alcohol and smoking were more than multiplicative for cirrhosis (P_interaction = 0.02) but not for gallbladder disease (P_interaction = 0.4).

Findings indicate that alcohol and smoking affect the risks of the 2 conditions in different ways. For cirrhosis, alcohol and smoking separately increase risk, and their joint effects are particularly hazardous. For gallbladder disease, alcohol reduces risk and smoking results in a small risk increase.

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