Cigarette smoking markedly increases liver inflammation in people infected with hepatitis C, according to a study published in the January 2003 edition of the journal Gut.
Between February 1998 and September 1999 French investigators recruited 244 patients with chronic hepatitis C infection to a study which involved a self- completed questionnaire and a liver biopsy to assess the impact of smoking on the severity of hepatitis C liver damage. The questionnaire included the following items: how old patients were when they started smoking; how long they had been smoking; and number of cigarettes smoked per day in the six months before the study. Patients were also asked about their daily alcohol intake. A liver biopsy was then performed. A total of 152 men and 92 women were recruited with an average age of just under 46 years. Nobody in the study was coinfected with either hepatitis B of HIV.
Liver samples were analysed and graded according to the degree of liver inflammation and fibrosis. Investigators found that the proportion of patients with moderate or marked liver inflammation increased in proportion with daily tobacco intake, with moderate or marked inflammation found in 62% of patients, who smoked between one and fifteen cigarettes a day, but in almost 82% of patients, who smoked more than 15 cigarettes a day. Likewise, the proportion of patients with mild liver inflammation fell as tobacco consumption increased.
Lifetime smoking was also found to be associated with liver inflammation, with 59% of non-smokers having moderate to marked inflammation, compared to 67.4% of light smokers (one to ten packs of cigarettes a year), 75.5% for moderate smokers (eleven to 20 packs per year), and 84.6% for heavy smokers (more than 20 packs per year).
Investigators also found that people who smoked were more likely to drink alcohol. To ensure that their study data were reliable and were not being influenced by alcohol consumption or age (known risk factors for liver inflammation), the investigators performed further analysis. This showed that being aged over 50, drinking more than two 10g units of alcohol a day (equal to a half pint of beer), and smoking fifteen or more cigarettes a day were all independently linked with moderate to marked liver inflammation.
However, investigators could not find a link between smoking and liver fibrosis. Only age over 50, drinking more than 30g of alcohol a day, and duration of hepatitis C infection were found to be significant.
The investigators also noted that smoking had a rapid effect on the liver, probably because of the liver’s role in metabolising nicotine. Although smoking was not associated with increased risk of fibrosis, the investigators speculate that this could “be explained by the fact that the duration of HCV infection was known only in half of the study population and probably did not overlap perfectly with the duration of smoking. They conclude, “cessation or reduction of tobacco consumption should…be recommended in patients with chronic hepatitis C.”
Further information on this website
Hezode C et al Impact of smoking on histological liver lesions in chronic hepatitis C Gut, 52:126-129, 2003.