Daily marijuana use was linked to increased HIV risk behavior in transgender women, but only among those with higher overall use | Research

The takeaway

A 60-day timeline follow-back study of 214 transgender women found that marijuana use on a given day was associated with greater odds of HIV transmission risk behavior during sex, but only among those with higher overall rates of marijuana use.

HIV prevention researchers; clinicians serving transgender populations; substance use counselors working with populations at high HIV risk.

Only marijuana (not alcohol or stimulants) was linked to HIV transmission risk behavior during sex

What the researchers found

Researchers collected 60-day timeline follow-back data from 214 transgender women in New York City to examine day-level links between substance use and sexual risk behavior.

All three substance types studied (heavy drinking, marijuana, stimulants) were associated with greater odds of any sexual activity on days when used.

Critically, only marijuana use was associated with increased odds of HIV transmission risk behavior (TRB) on days when sex occurred. This association was moderated by overall use frequency: the link between daily marijuana use and TRB was significant only among women with higher overall rates of marijuana use.

Heavy drinking showed a different pattern, with stronger effects on sexual activity among those with higher overall drinking rates. Stimulant use effects were stronger among those with lower overall stimulant use rates.

Why it matters

Transgender women face disproportionately high HIV rates. This study identifies marijuana use as specifically linked to sexual risk behavior (not just sexual activity), distinguishing it from alcohol and stimulants. This has implications for targeted HIV prevention interventions.

The numbers in context

214 transgender women. 60-day follow-back. All three substances linked to any sexual activity. Only marijuana linked to TRB on sex days. Marijuana-TRB link significant only among those with higher overall marijuana use rates.

How the study worked

Intensive longitudinal design using 60-day timeline follow-back interviews. 214 transgender women in NYC. Multilevel models testing day-level substance use as predictor of any sex and TRB, adjusting for overall use levels.

What this study cannot tell us

Observational design cannot prove marijuana causes risk behavior. NYC sample may not generalize. Timeline follow-back relies on retrospective recall. Specific sexual contexts and partner types were not fully characterized.

How to read the evidence

Moderate. Strong intensive longitudinal design with day-level data, but observational and limited to a single city.

When this study was published

Published in 2018. HIV prevention research among transgender women continues to address substance use as a key modifiable risk factor.

The bigger picture

Day-level studies capture what happens in real time rather than relying on general associations. The finding that marijuana specifically (not alcohol or stimulants) predicts risk behavior during sex points to something unique about how marijuana affects sexual decision-making in this population.

Questions still open

What is it about marijuana specifically that increases sexual risk behavior? Would marijuana reduction interventions decrease HIV acquisition among transgender women? Does this finding replicate in other high-risk populations?

Common questions

Why does marijuana affect sexual risk behavior differently than alcohol?

The study did not determine the mechanism, but marijuana may uniquely affect risk perception, partner negotiation, or willingness to use condoms in ways that differ from alcohol intoxication. The effect was dose-dependent (stronger in heavier users), suggesting a threshold effect.

What is HIV transmission risk behavior?

In this study, TRB refers to sexual acts that carry risk of HIV transmission, such as condomless receptive anal intercourse. The study distinguished between any sexual activity (which all substances increased) and specifically risky sexual activity (which only marijuana increased).

Read the original research

Day-Level Associations Between Substance Use and HIV Risk Behavior Among a Diverse Sample of Transgender Women.

Transgender health, 3(1), 210-219

View on PubMed ↗Publisher’s paper ↗

Citation

Millar, Brett M; English, Devin; Moody, Raymond L; Rendina, H Jonathon; Cain, Demetria; Antebi-Gruszka, Nadav; Carter, Joseph A; Parsons, Jeffrey T. (2018). Day-Level Associations Between Substance Use and HIV Risk Behavior Among a Diverse Sample of Transgender Women.. Transgender health, 3(1), 210-219. https://doi.org/10.1089/trgh.2018.0032