Self-reported lifetime marijuana use and interleukin-6 levels in middle-aged African Americans

Background: Research examining the relationship between marijuana and cytokine function has been well developed in the biochemical literature. However, scant literature exists regarding this relationship between inflammatory markers and marijuana use in public health or behavioral studies and is virtually nonexistent in non-neurologically compromised African American samples. Methods: The current study examined the differences in serum interleukin-6 (IL-6), a proinflammatory cytokine, between non-drug users (n = 78), marijuana only users (n =46) and marijuana plus other drugs users (n = 45) in a community-based sample of middle aged African Americans. Participants included 169 African American adults (50.30% female), with a mean age of 45.68 years (SD = 11.72 years) from the Washington, DC metropolitan area. Serum was drawn upon entry into the study and the participants completed a demographic questionnaire, which included questions regarding drug use history. Results: After adjusting for demographic and physiological covariates, analysis of covariance revealed a significant difference between the three groups, F(2, 158) = 3.08, p = 0.04). Post hoc analyses revealed lifetime marijuana only users had significantly lower IL-6 levels (M=2.20 pg/mL, SD = 1.93) than their lifetime nonuser counterparts (M = 3.73 pg/mL, SD = 6.28). No other comparisons among the groups were statistically significantly different. Conclusion: The current findings extend previous cellular and biochemical literature, which identifies an inverse association between IL-6 and marijuana use. Examining this relationship in the psychological and behavioral literature could be informative to the development of clinical interventions for inflammatory diseases. (C) 2014 Elsevier Ireland Ltd. All rights reserved.