High prevalence of cannabis use among Aka foragers of the Congo Basin and its possible relationship to helminthiasis.
Casey J Roulette, Mirdad Kazanji, Sébastien Breurec, Edward H Hagen
American journal of human biology : the official journal of the Human Biology Council January 1, 2016 Peer reviewed DOI: 10.1002/ajhb.22740 via PubMed
Summary
Among the Aka, a hunter-gatherer population in the Central African Republic, cannabis use is common: 70.9% of men and 6.1% of women, for a total prevalence of 38.6%. Cannabis users were younger and had less material wealth. Urinary levels of a cannabis biomarker were negatively associated with worm burden, and with reinfection one year after anthelmintic treatment. These findings support the hypothesis that cannabis use may be an unconscious form of self-medication against helminths.
Study at a glance
| Design | observational cohort |
|---|---|
| Sample size | 379 |
| Population | adult Aka foragers in the Lobaye district, Central African Republic |
| Key finding | Cannabis use was high among Aka men and negatively associated with helminth infection and reinfection, supporting a self-medication hypothesis. |
Abstract
Little is known about cannabis use in hunter-gatherers. Therefore, we investigated cannabis use in the Aka, a population of foragers of the Congo Basin. Because cannabis contains anthelminthic compounds, and the Aka have a high prevalence of helminthiasis, we also tested the hypothesis that cannabis use might be an unconscious form of self-medication against helminths. We collected self- and peer-reports of cannabis use from all adult Aka in the Lobaye district of the Central African Republic (n = 379). Because female cannabis use was low, we restricted sample collection to men. Using an immunoassay for Δ9-tetrahydrocannabinol-11-oic acid (THCA), a urinary biomarker of recent cannabis consumption, we validated cannabis use in men currently residing in camps near a logging road (n = 62). We also collected stool samples to assay worm burden. A longitudinal reinfection study was conducted among a subsample of the male participants (n = 23) who had been treated with a commercial anthelmintic 1 year ago. The prevalence of self- and peer-reported cannabis use was 70.9% among men and 6.1% among women, for a total prevalence of 38.6%. Using a 50 ng/ml threshold for THCA, 67.7% of men used cannabis. Cannabis users were significantly younger and had less material wealth than the non-cannabis users. There were significant negative associations between THCA levels and worm burden, and reinfection with helminths 1 year after treatment with a commercial anthelmintic. The prevalence of cannabis use among adult Aka men was high when compared to most global populations. THCA levels were negatively correlated with parasite infection and reinfection, supporting the self-medication hypothesis.