However,
based on other prior research, there is concern that frequent, heavy cannabis
use may promote the development of liver
fibrosis.
At the 57th annual meeting of the
American Association for the Study of Liver Diseases, held last month in Boston,
researchers from the University of California at San Francisco reported on a study
looking at the association between cannabis use and severity of fibrosis in individuals
with chronic hepatitis C virus (HCV) infection.
Between 2001 and 2004,
the researchers interviewed 204 HCV-infected subjects enrolled through university
and community sources, assessing demographics, risk factors for HCV, and use of
cannabis and alcohol. Participants also received virological testing and liver
biopsies, which were scored using the Ishak system (stages F0 to F6, from absent
to severe fibrosis).
Results
A majority of participants (69%) were men, 49% were Caucasian, 21% were coinfected
with HIV, most were low income, the median age was about 47 years, and for 70%
the presumed route of infection was injection drug use.
The median lifetime duration and average daily use of alcohol were 29.1 years
and 1.94 drink equivalents per day.
13.7% of subjects reported daily cannabis use within 12 months prior to enrollment,
while 45.1% reported occasional use and 41.2% said they never used cannabis.
Daily cannabis use (compared with occasional or no use) was strongly associated
with moderate to severe fibrosis by univariate analysis (odds ratio [OR] 3.21;
P = 0.020).
The same held true by multivariate analyses (OR 6.78; P = 0.003).
Other independent predictors of moderate to severe fibrosis were:
- lifetime
duration of moderate to heavy alcohol use (> 2 and > 4 drinks
per day in women and men, respectively; OR 1.72 per 10 years; P = 0.044) -
> 11 portal tracts (compared to < 5; OR 6.92; P = 0.021). - Patient
age was of borderline significance (OR 2.19 per 10 years; P = 0.064).
Daily cannabis use did not appear to be strongly associated with mild fibrosis
(F1-F2) compared to no fibrosis (F0) in univariate or multivariate analysis.
Independent predictors of mild fibrosis were:
- HCV viral load (OR 1.86
per log increase; P = 0.009); - 5-11 or > 11 portal tracts (compared
to < 5) (OR 3.43, P = 0.002 and OR 10.4, P < 0.001, respectively);
Patient sex, race, age, duration of HCV infection, HCV genotype, HIV status, body
weight, tobacco use, and lifetime alcohol use were not significantly associated
with mild fibrosis in this study.
Conclusion
"Current
daily cannabis use independently increased the odds of moderate to severe fibrosis
by nearly 7-fold in persons with chronic HCV infection," the researchers
concluded. "Our results indicate that HCV-infected individuals should be
counseled to reduce or abstain from cannabis use."
11/14/06
References
J
H Ishida, C Jin, P Bacchetti, and others. Influence of Cannabis Use on Severity
of Hepatitis C Disease. 57th AASLD. Boston, MA. October 27-31, 2006. Abstract
211.
D L Sylvestre,
B J Clements, Y Malibu. Cannabis use improves retention and virological outcomes
in patients treated for hepatitis C. European Journal of Gastroenterology and
Hepatology 18(10): 1057-1063. October 2006.
A majority of participants (69%) were men, 49% were Caucasian, 21% were coinfected
with HIV, most were low income, the median age was about 47 years, and for 70%
the presumed route of infection was injection drug use. 
