Objective: To ascertain the relationship between cannabis use, obesity, and insulin resistance.
Methods: Data on 786 Inuit adults from the Nunavik Inuit Health Survey (2004) were analyzed. Information on cannabis use was obtained from a self-completed, confidential questionnaire. Fasting blood glucose and insulin and homeostasis model assessment of insulin resistance (HOMA-IR) served as surrogate markers of insulin resistance. Analysis of covariance and multivariate logistic regression ascertained relationships between cannabis use and outcomes.
Results: Cannabis use was highly prevalent in the study population (57.4%) and was statistically associated with lower body mass index (BMI) (P < 0.001), lower % fat mass (P < 0.001), lower fasting insulin (P = 0.04), and lower HOMA-IR (P = 0.01), after adjusting for numerous confounding variables. Further adjustment for BMI rendered fasting insulin and HOMA-IR differences statistically nonsignificant between past-year cannabis users and nonusers. Mediation analysis showed that the effect of cannabis use on insulin resistance was indirect, through BMI. In multivariate analysis, past-year cannabis use was associated with 0.56 lower likelihood of obesity (95% confidence interval 0.37-0.84).
Conclusions: Cannabis use was associated with lower BMI, and such an association did not occur through the glucose metabolic process or related inflammatory markers. The association between cannabis use and insulin resistance was mediated through its influence on weight.
© 2014 The Obesity Society.