Does Cannabis Use Protect Against Obesity And Diabetes?Friday, September 4, 2015
Anyone even remotely familiar with cannabis use and its potential to cause the “munchies” would immediately assume that regular cannabis use would likely promote weight gain and, in consequence, the risk forf type 2 diabetes.
Thus, readers may well be as intrigued as I am by the work of Gerard Ngueta and colleagues from Québec, Canada, published in OBESITY, showing a rather strong inverse association between cannabis use and BMI in the Inuit.
The researchers analyzed data from 786 Inuit adults from the Nunavik Inuit Health Survey (2004), which included self-reported use of cannabis as well as measured levels of fasting blood glucose and insulin.
Not only was cannabis use highly prevalent in the study population (57%), but even after adjustment for a number of potential confounders, cannabis use was significantly associated with lower body mass index (BMI) (about 2 BMI points, P < 0.001), lower % fat mass (P < 0.001), lower fasting insulin (P = 0.04), and lower HOMA-IR (P = 0.01).
In multivariate analysis, past-year cannabis use was associated with 0.56 lower likelihood of obesity (95% confidence interval 0.37-0.84), and it was this relationship that fully explained the seemingly positive effect of cannabis use on insulin resistance (as a surrogate for diabetes risk).
It may also be worth noting that the association of cannabis use with lower BMI was only seen in past or non-smokers, but not in current tobacco smokers.
Now normally, being highly sceptical of these types of association studies, which are generally hopelessly confounded and can never prove causality, I would have dismissed this as a chance finding of little significance.
Imagine my surprise, however, when the authors go on to mention several previous studies, in a variety of populations, that have reported similar findings.
Unfortunately, the authors have little to offer in terms of a plausible biological mechanism and can only speculate on possible genetic or functional factors involving the cannabinoid system or putative effects on energy expenditure associated with the pulmonary consequences of smoking.
Thus, I can presently make little of this finding – but I will likely stay tuned.