Cannabis use disorder in women linked to 48% higher cardiovascular risk, especially stroke | Research

The takeaway

In a cohort of over 1.2 million pregnant women followed for up to 30 years, cannabis use disorder was associated with 48% higher risk of cardiovascular hospitalization, with a particularly strong link to hemorrhagic stroke.

Women who use cannabis, cardiologists, and women's health researchers.

2.08x hemorrhagic stroke risk with cannabis use disorder

What the researchers found

Women with cannabis use disorders had 1.48 times the risk of cardiovascular hospitalization (95% CI 1.27-1.72). Cannabis with other substances had stronger association (HR 1.84) than cannabis alone (HR 1.30, borderline significant). Cannabis use disorder was strongly associated with hemorrhagic stroke even after adjusting for other substance use (HR 2.08, CI 1.07-4.05). Cardiovascular hospitalization incidence was 58.4 vs 33.6 per 10,000 person-years.

Why it matters

This is one of the largest and longest studies examining cannabis and cardiovascular risk in women, providing evidence that cannabis use disorder may have lasting cardiovascular consequences.

The numbers in context

1,247,035 women. 18,998,986 person-years. Overall CVD: HR 1.48 (95% CI 1.27-1.72). Cannabis alone: HR 1.30. Cannabis + other substances: HR 1.84. Hemorrhagic stroke: HR 2.08 (95% CI 1.07-4.05).

How the study worked

Longitudinal cohort of 1,247,035 pregnant women in Quebec, Canada (1989-2019). 18,998,986 person-years of follow-up. Cox regression adjusted for patient characteristics.

What this study cannot tell us

Cannabis use disorder identified by diagnostic codes (may miss non-disordered use). Confounding by other substance use partially addressed but not eliminated. Healthy user bias possible.

How to read the evidence

Very large longitudinal cohort with long follow-up, though subject to diagnostic code limitations and residual confounding.

When this study was published

2020 study using 1989-2019 data.

The bigger picture

The hemorrhagic stroke finding is particularly concerning for young women, as stroke in this population is relatively rare but has devastating consequences.

Questions still open

Is the cardiovascular risk from cannabis itself or from lifestyle factors associated with cannabis use disorder? Does the hemorrhagic stroke risk apply to recreational users without a diagnosed disorder?

Common questions

Does cannabis increase heart disease risk in women?

In this study of 1.2 million women, cannabis use disorder was associated with 48% higher cardiovascular hospitalization risk over up to 30 years, with hemorrhagic stroke risk roughly doubled.

Is the cannabis cardiovascular risk independent of other drug use?

Cannabis alone showed a borderline significant 30% increase in risk, while cannabis with other substances showed 84% higher risk. Hemorrhagic stroke remained significant even after adjusting for other substances.

Read the original research

Cannabis use disorder and the future risk of cardiovascular disease in parous women: a longitudinal cohort study.

BMC medicine, 18(1), 328

View on PubMed ↗Publisher’s paper ↗

Citation

Auger, Nathalie; Paradis, Gilles; Low, Nancy; Ayoub, Aimina; He, Siyi; Potter, Brian J. (2020). Cannabis use disorder and the future risk of cardiovascular disease in parous women: a longitudinal cohort study.. BMC medicine, 18(1), 328. https://doi.org/10.1186/s12916-020-01804-6