BEHAVIORAL ECOLOGY OF TOBACCO AND CANNABIS USE AMONG AKA FORAGERS OF THE ...

187 Pages·2015·7.73 MB·English

BEHAVIORAL ECOLOGY OF TOBACCO AND CANNABIS USE AMONG AKA FORAGERS OF THE
CONGO BASIN

By
CASEY JORDAN ROULETTE

A dissertation submitted in partial fulfillment of
the requirements for the degree of

DOCTOR OF PHILOSOPHY

WASHINGTON STATE UNIVERSITY
Department of Anthropology

MAY 2015

© Copyright by CASEY JORDAN ROULETTE, 2015
All Rights Reserved
© Copyright by CASEY JORDAN ROULETTE, 2015
All Rights Reserved
To the Faculty of Washington State University:

The members of the Committee appointed to examine the dissertation of CASEY JORDAN
ROULETTE find it satisfactory and recommend that it be accepted.

___________________________________
Edward H. Hagen, Ph.D., Chair

___________________________________
Barry S. Hewlett, Ph.D.

___________________________________
Robert J. Quinlan, Ph.D.

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ACKNOWLEDGEMENT

I would like to thank my committee for their guidance, expertise, patience, and trust.
These are: Edward Hagen, my PhD chair, who introduced me to evolutionary approaches to substance
use and provided countless hours of mentoring and advice; Barry Hewlett, who opened my mind to
anthropology and who introduced me to the Aka; Rob Quinlan, who introduced me to field work and urged
me to apply to the evolutionary anthropology program.

None of this would have been possible without the Aka, who graciously agreed to participate, who found
humor in the questions and tasks asked of them, and who provided assistance in the field. It has truly
been a great experience working and spending time with them. I would also like to thank the people of the
villages of Bagandou, Kenga, and Moboma, CAR, for their hospitality, especially my research assistants,
Mesmin Dopeningue, the late Nicaise Molende, Alaine Guy Kolet, Aubin Mongosso, and Eduard Mboula,
without who’s help the project never would have been completed.

There are several professors, colleagues, and associates who helped along the way.
These include Dr’s Marsha Quinlan, Bonnie Hewlett, Nicole Hess, Brian Kemp, Colin Grier, Courtney
Meehan, Cara Monroe, and Roger Sullivan, who provided additional support and guidance. Also, Haley
Mann, Jennifer Roulette, Mark Remiker, Mirdad Kazanji and the rest of the staff at Institute Pasteur in
Bangui, all of whom helped in data collection and/or analyses. Thanks also to Elsevier and John Wiley
and Sons for permission to reprint, as well as to the anonymous reviewers for their comments and
suggestions.

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Finally, I would like to thank my family. These include my parents--Marie and Fred Snaza, Scott and
Debora Roulette, and Steve and Ellen Wilcox—as well as my sister, Saidi Roulette, for believing in and
never giving up on me, and for all of their support. My wonderful daughter, Emma, who provided me with
a new focus and perspective that helped propel me through the finish line. And most importantly, my
amazing wife and colleague, Jennifer Ellen Wilcox Roulette, with whom I shared this journey and whose
love and support made it all possible.

Thank you all!

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BEHAVIORAL ECOLOGY OF TOBACCO AND CANNABIS USE AMONG AKA FORAGERS OF THE
CONGO BASIN
Abstract

by Casey Jordan Roulette, Ph.D.
Washington State University
May 2015

Chair: Edward H.Hagen

Little is known about substance use among extant hunting-gathering populations. I therefore
conducted one of the first biocultural, and biomarker validated, studies of tobacco and cannabis among
the Aka foragers of the Congo Basin. Because tobacco and cannabis contain anthelmintic compounds,
and because the Aka suffer from high rates of helminthiasis, I also tested a hypothesis that recreational
use of neurotoxic plants helps defend against parasites.
Self- and peer-reports of tobacco and cannabis were collected from all Aka residing in the study
area (n=379). Detailed questions about substance use were asked among a subset of these. Because
female use was low, I restricted saliva, urine and stool sample collections to men. Saliva samples were
assayed for cotinine, a nicotine metabolite; urine samples were assayed for THCA, a metabolite of THC;
a subsample was genotyped for the CYP2A6 enzyme, which metabolizes nicotine. Stool samples were
assayed for intestinal helminth eggs as an index of worm burden.
Aka men pay more for tobacco, yet have a higher smoking prevalence (95%) than men in most
other populations, whereas Aka women have a low prevalence. Aka thus have one of the largest known
gender differences in smoking. Tobacco is widely shared, and might play a central role in this defining
aspect of Aka culture. Significant negative correlations between cotinine and worm burden and THCA and
worm burden were found. Treating helminths with a commercial anthelmintic reduced cotinine
concentration two weeks later, compared to placebo controls. Significant negative rank correlations were
found between year 1 cotinine concentrations and reinfection by year 2 and between year 2 THCA

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concentrations and reinfection. Finally, younger and older participants with slow nicotine-metabolizing
alleles had lower worm burdens compared to those with extensive metabolizing alleles.
Tobacco advertising cannot easily explain the high prevalence of smoking among Aka men, nor
can socioeconomic disparities, proscriptions, or the addictiveness of nicotine easily explain the low
prevalence among Aka women. Aka smoking might be better explained by internal, rather than external,
cultural and political-economic factors. In addition, these results provide the first support for the
hypothesis that substance use helps defend against parasites.

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TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS ....................................................................................................................... iii
ABSTRACT .............................................................................................................................................v
LIST OF TABLES ..................................................................................................................................ix
LIST OF FIGURES .................................................................................................................................x
1. INTRODUCTION ...............................................................................................................................1
2. PUZZLE OF HIGH MALE TOBACCO USE, AND LOW FEMALE USE, AMONG CONGO
BASIN FORAGERS: IMPLICATIONS FOR ANTHROPOLOGICAL THEORIES OF DRUG USE
AND PUBLIC HEALTH ..........................................................................................................................7
ABSTRACT ...........................................................................................................................................8
INTRODUCTION ....................................................................................................................................9
METHODS ..........................................................................................................................................16
RESULTS ...........................................................................................................................................18
DISCUSSION ......................................................................................................................................32
CONCLUSIONS ...................................................................................................................................40
ACKNOWLEDGEMENTS .......................................................................................................................41
REFERENCES ....................................................................................................................................43
3. TOBACCO USE VS. HELMINTHS IN CONGO BASIN HUNTER-GATHERERS: SELF-
MEDICATION IN HUMANS? Roulette CJ, Mann H, Kemp BM, Remiker M, Roulette JW, Hewlett
BS, et al. (2014). Evolution and Human Behavior, 35(5):397-407.
http://dx.doi.org/10.1016/j.evolhumbehav.2014.05.005........................................................................50
ABSTRACT .........................................................................................................................................51
INTRODUCTION ..................................................................................................................................52
STUDY ..............................................................................................................................................58
MATERIALS AND METHODS .................................................................................................................63

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RESULTS ...........................................................................................................................................68
DISCUSSION AND LIMITATIONS ............................................................................................................74
ACKNOWLEDGEMENTS .......................................................................................................................81
REFERENCES ....................................................................................................................................82
LIST OF TABLES..................................................................................................................................96
FIGURE LEGENDS...............................................................................................................................98
FIGURES .........................................................................................................................................103
4. HIGH PREVALENCE OF CANNABIS USE AMONG AKA FORAGERS OF THE CONGO
BASIN, AND ITS POSSIBLE RELATIONSHIP TO HELMINTHIASIS ...............................................108
ABSTRACT .......................................................................................................................................109
INTRODUCTION ................................................................................................................................110
STUDY AIMS .....................................................................................................................................115
MATERIALS AND METHODS ................................................................................................................117
RESULTS .........................................................................................................................................122
DISCUSSION ....................................................................................................................................128
CONCLUDING REMARKS ...................................................................................................................135
ACKNOWLEDGEMENTS .....................................................................................................................136
REFERENCES ..................................................................................................................................137
LIST OF TABLES ................................................................................................................................143
FIGURE LEGENDS ............................................................................................................................147
FIGURES .........................................................................................................................................152
5. CONCLUSION ...............................................................................................................................157
APPENDIX .........................................................................................................................................162
A. Chapter 2 Supplementary Material ..........................................................................................163
B. Chapter 3 Supplementary Material ...........................................................................................168

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LIST OF TABLES

Chapter 1 Tables
1. Structured Survey Questions ..................................................................................................17
2. Demographic Variables ..........................................................................................................20
3. Epidemiology of tobacco based on self-report data ...............................................................22
4. Logistic regression models of female smoking vs. age and mother’s smoking ......................24
5. Economics of tobacco smoking ..............................................................................................25
6. Cultural attitudes of tobacco ...................................................................................................28
7. Composite salience scores .....................................................................................................30
Chapter 2 Tables
1. Baseline sample characteristics based on interview data and samples s1-s3 .......................96
2. ANCOVA model of follow-up cotinine concentration ..............................................................97
Chapter 3 Tables
1. Descriptive Statistics .............................................................................................................143
2. Logistic regression model of cannabis smoker status (THCA > 50 ng/ml) vs age and
material wealth score ............................................................................................................144
3. Negative binomial GLM models of worm burden score with log link ....................................145
4. OLS models of helminth reinfection score ............................................................................146

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