Does marijuana affect diabetes control?

With the legalization of marijuana in Canada, the effect of marijuana on diabetes control has become of considerable interest. This has historically been a difficult topic to study, given that marijuana wasn’t legal in Canada until just a few years ago (and still isn’t, in most countries in the world).

Diabetes Canada published a position statement on recreational use of marijuana in adults and adolescents with diabetes in 2019, soon after marijuana became legal in Canada. They identified only 6 studies on which to draw recommendations (4 of which were only abstracts from conference presentations).

The very limited data suggests:

significantly worse diabetes control in 1,004 people with type 1 diabetes who used marijuana, compared with those who didn’t (based on A1C)
higher risk of developing diabetes complications (peripheral arterial occlusion, heart attack, and kidney disease)
double the risk of diabetic ketoacidosis (DKA) – it is postulated that this may be related to marijuana altering gut motility, leading to vomiting and thus DKA

Regarding whether marijuana specifically affects insulin sensitivity or insulin production (beta cell function), there is very limited information. The existing data is mostly cross-sectional and observational, and thus packed with potential confounding factors. There may be a possible link between marijuana use and lower fasting glucose, lower fasting insulin and insulin resistance, but one or many confounding factors may be at play here, and I would not draw any conclusions based on the extremely limited data. Marijuana ‘munchies’, alteration in mental state (thereby affecting ability to make decisions about eg insulin dosing) can play a role in worsening diabetes control. Some people feel less stressed with cannabis use – could this reduce levels of hormones that drive sugars up, like adrenaline and cortisol? We don’t know the answer. For those who can feel paranoia as a side effect, could this increase adrenaline and cortisol, thereby increasing sugars? We don’t know.

Based on the existing (and gross lack of) data, Diabetes Canada advises that people with diabetes should not use recreational cannabis. For people with diabetes who choose to use cannabis, health care providers are advised to provide individualized assessment and counseling to keep their patient as safe and well managed as possible.

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