Injection Drug Use, Unemployment, and Severe Food Insecurity Among HIV-HCV Co-Infected Individuals: A Mediation Analysis
Severe food insecurity (FI), which indicates reduced food intake, is common among HIV-hepatitis C virus (HCV) co-infected individuals. Given the importance of unemployment as a proximal risk factor for FI, this mediation analysis examines a potential mechanism through which injection drug use (IDU) is associated with severe FI. We used biannual data from the Canadian Co-infection Cohort (N = 429 with 3 study visits, 2012–2015). IDU in the past 6 months (exposure) and current unemployment (mediator) were self-reported. Severe FI in the following 6 months (outcome) was measured using the Household Food Security Survey Module. An overall association and a controlled direct effect were estimated using marginal structural models. Among participants, 32% engaged in IDU, 78% were unemployed, and 29% experienced severe FI. After adjustment for confounding and addressing censoring through weighting, the overall association (through all potential pathways) between IDU and severe FI was: risk ratio (RR) = 1.69 (95% confidence interval [CI] = 1.15–2.48). The controlled direct effect (the association through all potential pathways except that of unemployment) was: RR = 1.65 (95% CI = 1.08–2.53). We found evidence of an overall association between IDU and severe FI and estimated a controlled direct effect that is suggestive of pathways from IDU to severe FI that are not mediated by unemployment. Specifically, an overall association and a controlled direct effect that are similar in magnitude suggests that the potential impact of IDU on unemployment is not the primary mechanism through which IDU is associated with severe FI. Therefore, while further research is required to understand the mechanisms linking IDU and severe FI, the strong overall association suggests that reductions in IDU may mitigate severe FI in this vulnerable subset of the HIV-positive population.
KeywordsHIV Hepatitis C virus Injection drug use Unemployment Severe food insecurity
TM is supported by a CANOC Centre Doctoral Scholarship Award, a joint program of CANOC and the CIHR Canadian HIV Trials Network (CTN 242). EEMM is supported by a Chercheur-Boursier (Junior 2) Career Award from the Fonds de recherche du Quebec-Sante (FRQ-S). MBK is supported by a Chercheurs Nationaux Career Award from the FRQ-S. The authors thank Jennifer Kocilowicz and Leo Wong for study coordination. The Canadian Co-infection Cohort investigators (CTN 222) are: Drs. Jeff Cohen (Windsor Regional Hospital Metropolitan Campus, Windsor, ON), Brian Conway (PENDER Downtown Infectious Diseases Clinic, Vancouver, BC), Curtis Cooper (The Ottawa Hospital Research Institute, Ottawa, ON), Pierre Côté (Clinique du Quartier Latin, Montreal, QC), Joseph Cox (McGill University Health Centre, Montreal, QC), John Gill (Southern Alberta HIV Clinic, Calgary, AB), Shariq Haider (McMaster University Medical Centre – SIS Clinic, Hamilton, ON), Aida Sadr (Native BC Health Center, St Paul’s Hospital, Vancouver, BC), Lynn Johnston (QEII Health Science Center for Clinical Research, Halifax, NS), Mark Hull (BC Centre for Excellence in HIV/AIDS, Vancouver, BC), Julio Montaner (St Paul’s Hospital, Vancouver, BC), Erica Moodie (McGill University, Montreal, QC), Neora Pick (Oak Tree Clinic, Children’s and Women’s Health Centre of British Columbia, University of British Columbia, Vancouver, BC), Anita Rachlis (Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON), Danielle Rouleau (Centre Hospitalier de l’Université de Montreal, Montreal, QC), Roger Sandre (Health Sciences North – The HAVEN/Hemophilia Program, Sudbury, ON), Joseph Mark Tyndall (Department of Medicine, Infectious Diseases Division, University of Ottawa, Ottawa ON), Marie-Louise Vachon (Centre Hospitalier Universitaire de Québec, Québec, QC), Steve Sanche (SHARE University of Saskatchewan, Saskatoon, SK), Stewart Skinner (Royal University Hospital & Westside Community Clinic, University of Saskatchewan, Saskatoon, SK), and David Wong (University Health Network, Toronto, ON).
This study was funded by the Canadian Institutes of Health Research (CIHR, MOP-79529) and the CIHR Canadian HIV Trials Network (CTN 264 & CTN 222).
Compliance with Ethical Standards
Conflicts of interest
JC has received grants for investigator-initiated clinical projects and consulting fees from: Gilead, ViiV Healthcare, and Merck. MBK has received grants for investigator-initiated trials from: ViiV Healthcare and Merck, as well as consulting fees from: Gilead, ViiV Healthcare, Merck, Bristol-Meyers Squibb, and AbbVie. The remaining authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
- 3.Anderson SA. Core indicators of nutritional state for difficult to sample populations. J Nutr. 1990;120(11):1559S–600S.Google Scholar
- 4.Health Canada. Canadian Community Health Survey, Cycle 2.2, Nutrition: Income-Related Household Food Security in Canada, 2004. http://www.hc-sc.gc.ca/fn-an/surveill/nutrition/commun/income_food_sec-sec_alim-eng.php (2004). Accessed 25 May 2017.
- 5.Tarasuk V, Mitchell A, Dachner N. Household food insecurity in Canada, 2014. http://proof.utoronto.ca (2014). Accessed 25 May 2017.
- 13.Remis RS. Modelling the incidence and prevalence of hepatitis C infection and its sequelae in Canada. Ottawa: Public Health Agency of Canada; 2007.Google Scholar
- 15.Anema A, Mehra D, Weiser SD, Grede N, Vogenthaler N, Kerr T. Drivers and consequences of food insecurity among illicit drug users (chapter 20). New York: Elsevier; 2015.Google Scholar
- 19.Kohlenberg B, Watts MW. Considering work for people living with HIV/AIDS: evaluation of a Group Employment Counseling Program. J Rehabil. 2003;69(1):22–9.Google Scholar
- 25.VanderWeele TJ. Explanation in causal inference: methods for mediation and interaction. Oxford: Oxford University Press; 2015.Google Scholar
- 36.Tarasuk V. Discussion paper on household and individual food insecurity. Ottawa: Health Canada; 2001.Google Scholar