Characterising the increasing prevalence of crystal methamphetamine use in Vancouver, Canada, from 2006-2017: A gender-based analysis.

INTRODUCTION: Methamphetamine use is increasing in North America and is associated with numerous negative health effects and social harms. As drug-related harms are often gendered, this study sought to examine the differential impacts of gender on the trends, risk factors and health implications of crystal methamphetamine use among a Canadian cohort of people with high rates of injection polysubstance use. METHODS: Data were collected from two prospective cohorts of people who inject drugs in Vancouver, Canada. We examined trends in reported crystal methamphetamine use from 2006-2017 using the Cochrane-Armitage test for trend. We used multivariable generalised estimating equations, stratified by gender, to determine independent risk factors and health outcomes associated with crystal methamphetamine use. RESULTS: In total, 1984 participants were included in the study, including 694 (35%) women. The prevalence of reported crystal methamphetamine use within the previous 6 months rose from 19% in 2006 to 36% in 2017, with a rise seen in both genders (P < 0.001). Reported crystal methamphetamine use was associated with numerous risk behaviours and drug-related harms in both genders, and in women it was associated with an increase in experiences of sexual violence (adjusted odds ratio 1.64, 95% confidence interval 1.18, 2.27). CONCLUSIONS: These findings demonstrate the rising prevalence of reported crystal methamphetamine use in Vancouver in a cohort with high rates of polysubstance use. This work highlights drug and sex-related risk behaviours associated with crystal methamphetamine use for both genders, and underscores the need to develop strategies to address the growing use of crystal methamphetamine.