Cannabis use reduces risk of insulin resistance in people with HIV/HCV co-infection

Cannabis use is associated with a reduced risk of insulin resistance in people with HIV and hepatitis C virus (HCV) co-infection, French investigators report in the online edition of Clinical Infectious Diseases. Cannabis users – irrespective of the frequency of use – were 60% less likely to have insulin resistance (IR) than non-users.

“This is the first longitudinal study documenting the relationship between the reduced risk of IR and cannabis in a population particularly concerned by IR risk,” comment the authors. “The results found were robust as they were confirmed in 3 sensitivity analyses.”

HCV infection is associated with an increased risk of insulin resistance and type 2 diabetes. A health concern in its own right, insulin resistance is also associated with a poorer response to interferon-based anti-HCV therapies.

Many people with HCV are co-infected with HIV, which has also been associated with insulin resistance. The reasons for this could include the inflammatory effects of untreated HIV, lifestyle factors, and disturbances in the lipid metabolism caused by some antiretroviral drugs.

Cannabis use is common among people with HIV and HCV. Consumption of the drug can increase appetite (and weight gain), but its use has also been associated with reduced obesity, and may therefore reduce the risk of insulin resistance.

Little is known about the effect of cannabis use on the risk of insulin resistance and diabetes. The few studies that have been conducted showed that use of the drug was associated with lower fasting insulin, reduced risk of insulin resistance and a lower risk of diabetes.

Investigators from the French ANRS CO13 HEPAVIH study monitored 703 people with HIV and HCV co-infection for 60 months to see if cannabis use reduced the risk of insulin resistance.

Participants in the study were evaluated at baseline and then every twelve months. At each study visit, they completed a questionnaire concerning the frequency of their use of cannabis in the past four weeks – never, sometimes, frequently, daily. Data were also gathered on other variables that have been shown to have an association with insulin resistance, which was defined as HOMA-IR >2.77.

Most (n = 459) of the participants were men and the median age was 45 years. At the first study visit, recent cannabis use was reported by 45% of participants, with 21% saying they used the drug occasionally, 12% reporting regular use and 13% daily cannabis consumption. The median HOMA-IR value at baseline was 2.06.

Overall, 46% of participants had at least one HOMA-IR value above 2.77 during follow-up.

The authors’ first analysis showed that cannabis consumption at any level was associated with a reduced risk of insulin resistance. Other factors associated with a decreased risk of insulin resistance included drinking three or more cups of coffee a day, gender, and detectable HIV viral load. The older antiretroviral staduvine (d4T) was the only anti-HIV drug associated with insulin resistance. Liver cirrhosis increased the risk of insulin resistance by approximately 50%, and the risk was increased four-fold by obesity.

In multivariate analysis, the relationship between cannabis use at any level and reduced risk of insulin resistance (OR = 0.4; 95% CI, 0.2-06) was confirmed after taking into account gender, HIV viral load, use of stavudine and coffee consumption.

Sensitivity analyses also confirmed the association between use of cannabis and reduced risk of insulin resistance.

The investigators note that the association they found between cannabis use, obesity and reduced risk of insulin resistance is consistent with earlier research in the US and also the findings of laboratory studies.

“There are several cannabis-based pharmacotherapies which do not rely on herbal marijuana and are used for specific indications (e.g. symptoms relief of multiple sclerosis),” conclude the authors. “The benefits of these products for patients concerned by increased risk of insulin resistance and diabetes need to be evaluated in clinical research and practice.”