Total and differential white blood cell count in cannabis users: results from the cross-sectional National Health and Nutrition Examination Survey, 2005-2016.

BACKGROUND: Elevated white blood cell (WBC) count in tobacco cigarette smokers compared to non-smokers has been well documented, but little is known on circulating WBC counts and cannabis use.
METHODS: The National Health and Nutrition Examination Survey (2005-2016) is designed to be nationally representative of United States non-institutionalized population. The current study includes adult participants 20-59 years of age (n = 16,430) who underwent a detailed examination in the mobile examination center (MEC). Cannabis use was measured using Audio Computer-Assisted Self-Interview. Cannabis use was classified into never, former, occasional (1-7 days of the past 30 days), and heavy (> 7 days of the past 30 days). WBC count was measured using the Coulter Counter method.
RESULTS: Total WBC count was higher among heavy cannabis users when compared to never users (β = 189; 95% confidence interval: 74, 304, p = 0.001). Among circulating WBC types, modest differences were observed for neutrophil count. Neither former nor occasional cannabis use was associated with total or differential WBC counts.
CONCLUSIONS: A modest association between heavy cannabis use and WBC count was detected. Additional research is needed to understand the immune related effects of different modes of cannabis use and to elucidate the role of proinflammatory chemicals generated from smoking cannabis.