Self-reported cannabis use and biomarkers of inflammation among adults in the United States

BACKGROUND: Cannabis is among the most frequently used substance in United States (U.S.). Studies evaluating the association between cannabis use and inflammation in humans have been few and have not explored potential sex-dependent effects. OBJECTIVE: To examine the relationship between self-reported cannabis use and high-sensitivity C-reactive protein (hsCRP), Interleukin 6 (IL-6) and fibrinogen. METHODS: We used Wave 1 of the Population Assessment of Tobacco and Health (PATH) – a nationally representative sample of adults in the U.S. Weighted linear regression models were used to determine associations of self-reported cannabis use with natural log-transformed hs-CRP, IL-6 and fibrinogen, adjusting for sociodemographic and psychosocial factors. RESULTS: Self-reported cannabis use, particularly cannabis use within the past 30 days, was associated with lower levels of each biomarker of systemic inflammation, although findings were imprecise. Specifically, in multivariable models, the associations between respondents who self-reported cannabis use in the past 30 days compared to never use was imprecise for hs-CRP (β ​= ​−0.15, 95% confidence interval (CI): −0.32, 0.00), IL-6 (β ​= ​− 0.02, 95% CI: −0.10, 0.05) and fibrinogen (β ​= ​− 0.01, 95% CI: −0.04, 0.02). We did not find that these associations differed significantly by sex. DISCUSSIONS: Data from this nationally representative study suggest potential anti-inflammatory effects of recent cannabis use. Additional studies that biologically measure the THC and CBD concentrations of the cannabis used and employ prospective and or experimental study designs investigate cannabis and inflammation associations are needed.