Cannabis smoking did not prevent people from quitting cigarettes in a large cancer society study | Research

The takeaway

Among 4,535 cigarette smokers followed for about 3 years, cannabis smoking status had no significant effect on rates of quitting cigarettes, regardless of how frequently cannabis was used.

Smoking cessation counselors, addiction medicine specialists, and public health researchers.

No significant difference in cigarette quit rates regardless of cannabis use status

What the researchers found

Adjusted cigarette quitting rates did not differ by cannabis status: never cannabis users (36.2%), former users (34.1%), and recent users (33.6%). Among recent cannabis smokers, quitting rates were similar across low (31.4%), moderate (36.7%), and high frequency (34.4%) use groups.

Why it matters

As cannabis use increases, clinicians have worried it might make cigarette cessation harder. This large, well-designed study found no evidence supporting that concern.

The numbers in context

Sample: 4,535 smokers. Follow-up: 3.1 years average. Quit rates: never cannabis 36.2%, former 34.1%, recent 33.6%. By frequency: low 31.4%, moderate 36.7%, high 34.4%. Intention to quit in 30 days: no difference (p=0.83).

How the study worked

Longitudinal study of 4,535 adult cigarette smokers from the American Cancer Society Cancer Prevention Study-3, enrolled 2009-2013 with follow-up in 2015-2017 (mean 3.1 years). Cannabis status was retrospectively assessed at baseline. Models adjusted for sociodemographics, smoking behaviors, and health factors.

What this study cannot tell us

Self-reported cannabis and cigarette use. Retrospective cannabis status assessment. Follow-up was about 3 years; longer-term effects are unknown. Participants in a cancer prevention study may not be representative.

How to read the evidence

Large cohort with longitudinal design and appropriate adjustments, though self-reported measures limit precision.

When this study was published

Published in 2021 with follow-up from 2009-2017.

The bigger picture

The lack of association between cannabis use and cigarette cessation suggests clinicians can address each substance independently rather than assuming one prevents quitting the other.

Questions still open

Does the mode of cannabis consumption matter (smoking vs. edibles) for cigarette cessation outcomes? Would results differ in populations with more heavy cannabis use?

Common questions

Does smoking cannabis make it harder to quit cigarettes?

This study of over 4,500 smokers found no evidence of that. Cigarette quit rates were similar whether participants never used cannabis, formerly used it, or currently used it.

Did heavier cannabis use matter?

No. Among recent cannabis smokers, quit rates were similar whether they used cannabis 3 days a month or 20+ days a month.

Read the original research

Association between Smoking Cannabis and Quitting Cigarettes in a Large American Cancer Society Cohort.

Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology, 30(10), 1956-1964

View on PubMed ↗Publisher’s paper ↗

Citation

Westmaas, J Lee; Strollo, Sara E; Newton, Christina C; Carter, Brian D; Diver, W Ryan; Flanders, W Dana; Stevens, Victoria L; Patel, Alpa V; Alcaraz, Kassandra I; Thrul, Johannes; Jacobs, Eric J. (2021). Association between Smoking Cannabis and Quitting Cigarettes in a Large American Cancer Society Cohort.. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology, 30(10), 1956-1964. https://doi.org/10.1158/1055-9965.EPI-20-1810