Thanks to the widespread availability of potent combination anti-HIV therapy (commonly called ART or HAART), many HIV-positive people are living longer and researchers increasingly expect that some of these people will reach old age. As HIV-positive people age, their risk for type 2 diabetes and other complications related to aging will likely increase. The precursor to type 2 diabetes is insulin resistance and we discuss this next.

The hormone insulin helps to move sugar (glucose) from the blood to cells. Inside cells, this sugar is converted into energy. Relatively steady levels of blood sugar are needed to help the body’s organs perform at their best. In some people, cells become less sensitive to insulin—a development called insulin resistance. To compensate, the pancreas gland produces more insulin, and this works for a while, in some cases for years. But, over time,unless steps are taken to reverse insulin resistance with the guidance of a physician, the problem can grow worse. Eventually, despite increased insulin production, resistance to the effects of this hormone becomes overwhelming and type 2 diabetes develops.

As part of a study (called ANRS HEPAVIH CO-13) researchers in Marseilles and elsewhere in France have been monitoring the health of HIV-positive adults co-infected with hepatitis C virus. Researchers collected information from participants by means of questionnaires, blood samples and several assessments. Some of the questions posed to participants dealt with the use of substances, including marijuana.

Researchers found a statistical relationship between the use of marijuana and a possibly decreased risk for insulin resistance.

Study details

The total number of participants in the study was 1,324 people. However, researchers excluded those who had diabetes or insufficient data for the final analysis. This left 703 participants, who were the focus of this analysis. The profile of these 703 participants upon entering the study was as follows:

• 68% men, 32% women
• average age – 44 years
• most participants (69%) had a CD4+ count greater than 350 cells/mm³
• most participants (72%) had a viral load less than 50 copies/ml

Results

The questionnaire asked participants if they used marijuana and how often.

The researchers found that at their first study visit, 46% of participants disclosed that they had used marijuana in the previous four weeks, distributed as follows:

• occasional use – 21%
• regular use – 12%
• daily use – 13%

Taking many factors into account, researchers found that participants who used marijuana were less likely to have insulin resistance.

Also, the researchers found that drinking coffee was associated with a decreased risk for having insulin resistance.

Bear in mind

The present study was observational in design. Such studies cannot draw firm conclusions between cause and effect. In other words, this study cannot prove that marijuana use did indeed reduce the risk of having insulin resistance. Observational studies can never rule out the possibility of some other unmeasured factor being present that might have skewed conclusions when interpreting the data. The findings from this study therefore need to be taken cautiously. However, the study is a good first step to establish a possible link between marijuana use and a decreased risk of insulin resistance in HIV-positive people. Such a study was necessary because some observational data from HIV-negative people in the U.S. also suggest an association between marijuana exposure and a reduced risk for insulin resistance. Doctors in Quebec working with Inuit people have also found, in an observational study, that marijuana may help reduce the risk of insulin resistance. Despite these findings, other observational studies in HIV-negative people have not found a beneficial association between marijuana and insulin resistance.

The need for good data

Doctors who treat people with insulin resistance need firm data from which to make recommendations about the safety and potential of marijuana for managing this condition. There are many questions that require answers that are relevant to the issue of insulin resistance, such as the following:

• What does marijuana do to human metabolism to reduce the risk of insulin resistance?
• What compounds in marijuana may be responsible for reducing the risk of insulin resistance?
• How often should marijuana be used to help reduce the risk of insulin resistance?
• Which is more effective at reducing the risk for insulin resistance—coffee or marijuana?
• Is marijuana as effective as the widely used and relatively cheap insulin sensitizer metformin? (Note that metformin itself is based on an extract from a plant—French lilac.)
• In what form should marijuana be taken (smoked or eaten) to have the best effect against insulin resistance?
• Will marijuana help everyone with insulin resistance?
• Does marijuana interact with other medicines used to treat insulin resistance?
• How safe is marijuana for people with insulin resistance and other co-existing illnesses such as cardiovascular disease, lung disease and so on?

The present French study was not designed to answer these important questions. However, robustly designed clinical trials could be developed to provide firm answers to these and other questions around insulin resistance and the potential medical use of marijuana. Such trials will likely be costly and it will take time to implement and eventually interpret the data captured. In the meantime, by working with a doctor, making changes to the diet, exercising regularly and taking prescribed medication, it is possible to control and decrease insulin resistance and reduce the risk for type 2 diabetes.

Resources

• The Diabetes Drill – Positive Side
• Canadian survey compares marijuana use across different conditions – CATIE News
• About Diabetes – Canadian Diabetes Association
• Diabetes – Health Canada

—Sean R. Hosein

REFERENCES:

1. Witters LA. The blooming of the French lilac. Journal of Clinical Investigation. 2001 Oct;108(8):1105-7.
2. Carrieri MP, Serfaty L, Vilotitch A, et al. Cannabis use and reduced risk of insulin-resistance in HIV-HCV infected patients: a longitudinal analysis (ANRS HEPAVIH CO-13). Clinical Infectious Diseases. 2015; in press.
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