Gender, sexual orientation identity, and initiation of amphetamine injecting among people who inject drugs: Examination of an expanding drug era in Montreal, Canada, 2011-19

Stine Bordier Høj; Nanor Minoyan; Geng Zang; Sarah Larney; Julie Bruneau

doi:10.1016/j.drugalcdep.2023.110956

Gender, sexual orientation identity, and initiation of amphetamine injecting among people who inject drugs: Examination of an expanding drug era in Montreal, Canada, 2011-19

Drug Alcohol Depend. 2023 Oct 1:251:110956. doi: 10.1016/j.drugalcdep.2023.110956. Epub 2023 Sep 9.

Authors

Stine Bordier Høj¹, Nanor Minoyan², Geng Zang³, Sarah Larney⁴, Julie Bruneau⁵

Affiliations

¹ Research Centre, Centre Hospitalier de l'Université de Montréal, 900 Rue Saint Denis, Montreal H2X 0A9, Canada. Electronic address: stine.hoj.chum@ssss.gouv.qc.ca.
² Research Centre, Centre Hospitalier de l'Université de Montréal, 900 Rue Saint Denis, Montreal H2X 0A9, Canada; Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, 7101 Avenue du Parc, Montreal H3N 1X9, Canada.
³ Research Centre, Centre Hospitalier de l'Université de Montréal, 900 Rue Saint Denis, Montreal H2X 0A9, Canada.
⁴ Research Centre, Centre Hospitalier de l'Université de Montréal, 900 Rue Saint Denis, Montreal H2X 0A9, Canada; Department of Family Medicine and Emergency Medicine, Université de Montréal, 2900 Boulevard Édouard-Montpetit, Montreal H3T 1J4, Canada.
⁵ Research Centre, Centre Hospitalier de l'Université de Montréal, 900 Rue Saint Denis, Montreal H2X 0A9, Canada; Department of Family Medicine and Emergency Medicine, Université de Montréal, 2900 Boulevard Édouard-Montpetit, Montreal H3T 1J4, Canada. Electronic address: julie.bruneau@umontreal.ca.

PMID: 37716286
DOI: 10.1016/j.drugalcdep.2023.110956

Abstract

Background: Amphetamine injection is expanding in North America and has been associated with male homosexuality among people who inject drugs (PWID). Applying subcultural evolution theory, we examined overall and gender-stratified trends in amphetamine injection and assessed sexual orientation as a gender-specific predictor of initiation among PWID in Montreal, Canada.

Methods: Data were from HEPCO, an open prospective cohort of PWID. Gender and sexual orientation were self-identified at enrolment. Interviewer-administered questionnaires at three-monthly (HCV RNA-negative participants) or yearly (RNA-positive) intervals captured past three-month amphetamine injection and covariates. Annual prevalence and linear trends in amphetamine injection were estimated using GEE. Incidence was computed among naïve individuals and hazard ratios for initiation estimated using gender-stratified, time-varying Cox regression models.

Results: 803 participants contributed 8096 observations between March 2011 and December 2019. Annual prevalence of amphetamine injecting increased from 3.25% [95%CI: 2.06-4.43%] to 12.7% [9.50-16.0] (trend p<0.001). Bivariate Cox regression models suggested similar and divergent predictors of initiation by gender. Incidence was 3.27 per 100 person-years [95%CI: 2.51-4.18] among heterosexual men, 7.18 [3.50-13.2] among gay/bisexual men, 1.93 [0.78-4.02] among heterosexual women and 5.30 [1.69-12.8] among gay/bisexual women. Among men, gay/bisexual identity doubled risk of initiation after adjusting for age, ethnicity, calendar year (aHR 2.16 [1.07-4.36]) and additional covariates (2.56 [1.24-5.30]). Among women, evidence for an association with gay/bisexual identity was inconclusive (aHR 2.63 [0.62-11.2]) and sample size precluded further adjustment CONCLUSIONS: Prevalence of amphetamine injection among PWID increased four-fold from 2011 to 2019, with elevated risk of initiation in gay and bisexual men.

Keywords: Injection drug use; LGBT; MSM; Methamphetamine; Psychostimulants; Sexual orientation.