Cannabis Smoking and Diabetes Mellitus: Results from Meta-analysis with Eight Independent Replication Samples.

BACKGROUND

In preclinical animal studies, evidence links cannabis with hyperphagia, obesity, and insulin resistance. Epidemiologic data, however, suggest an inverse cannabis smoking-diabetes mellitus association. Here, we offer epidemiologic estimates from eight independent replications from (1) the National Health and Nutrition Examination Surveys, and (2) the National Surveys on Drug Use and Health (2005-2012).

METHODS

For each national survey participant, computer-assisted self-interviews assess cannabis smoking and physician-diagnosed diabetes mellitus; the National Health and Nutrition Examination Surveys provide additional biomarker values and a composite diabetes diagnosis. Regression analyses produce estimates of cannabis smoking-diabetes associations. Meta-analyses summarize the replication estimates.

RESULTS

Recently active cannabis smoking and diabetes mellitus are inversely associated. The meta-analytic summary odds ratio is 0.7 (95% confidence interval = 0.6, 0.8).

CONCLUSIONS

Current evidence is too weak for causal inference, but there now is a more stable evidence base for new lines of clinical translational research on a possibly protective (or spurious) cannabis smoking-diabetes mellitus association suggested in prior research.