Genetic risk for cannabis use disorder overlapped with genetic risk for severe COVID-19 | Research

The takeaway

Genetic vulnerability to cannabis use disorder was significantly correlated with genetic vulnerability to COVID-19 hospitalization, even after accounting for tobacco, alcohol, BMI, and respiratory conditions.

Genetics researchers, public health officials studying COVID-19 risk factors, and addiction researchers.

Genetic correlation of 0.42 between CUD and COVID-19 hospitalization

What the researchers found

The genetic correlation between CUD and COVID-19 hospitalization was 0.423 (p = 1.33 x 10^-6). This association remained significant after controlling for genetic liability to tobacco use, alcohol misuse, BMI, lung function, education, COPD, hypertension, diabetes, and other factors (b = 0.381-0.539). However, causal inference models found no evidence that CUD directly causes severe COVID.

Why it matters

Finding shared genetic architecture between CUD and COVID-19 severity suggests overlapping biological pathways, potentially involving immune function or inflammation. This goes beyond behavioral risk factors like smoking to point toward deeper biological connections.

The numbers in context

CUD GWAS: 14,080 cases, 343,726 controls. COVID-19 hospitalization GWAS: 9,373 cases, 1,197,256 controls. Genetic correlation: r_G = 0.423. Association persisted after adjusting for 13 covariates (b = 0.381-0.539). No significant causal effect detected.

How the study worked

Genomic analysis using summary statistics from genome-wide association studies of CUD (14,080 cases, 343,726 controls) and COVID-19 hospitalization (9,373 cases, 1,197,256 controls). Genetic correlation was estimated and adjusted for covariates using genomic structural equation modeling. Latent causal variable models tested for putative causation.

What this study cannot tell us

Genetic correlation analyses cannot establish causation. GWAS data were from pre-pandemic CUD studies and early pandemic COVID-19 data. Cannot determine specific shared biological pathways. Results apply at population level, not individual prediction.

How to read the evidence

Large-scale genomic data with rigorous covariate adjustment. Novel finding but genetic correlation studies have inherent limitations in identifying mechanisms.

When this study was published

2021 study using pre-pandemic CUD genetics and early pandemic COVID-19 data.

The bigger picture

Shared genetic architecture does not mean one condition causes the other. The overlapping genetics between CUD vulnerability and COVID-19 severity may point to common biological mechanisms involving immune regulation or inflammatory response that future research could target.

Questions still open

What specific biological pathways are shared between CUD vulnerability and COVID-19 severity? Does active cannabis use (not just genetic liability) affect COVID-19 outcomes? Would these genetic overlaps hold for other respiratory infections?

Common questions

Does cannabis use cause worse COVID-19 outcomes?

This study found shared genetics but no evidence of direct causation. People genetically predisposed to CUD were also genetically predisposed to COVID-19 hospitalization, but the causal models did not support one causing the other.

Could the connection just be about smoking?

The genetic overlap persisted even after accounting for tobacco use, COPD, lung function, and other respiratory factors, suggesting the connection goes beyond combustible substance use.

Read the original research

Genetic Liability to Cannabis Use Disorder and COVID-19 Hospitalization.

Biological psychiatry global open science, 1(4), 317-323

View on PubMed ↗Publisher’s paper ↗

Citation

Hatoum, Alexander S; Morrison, Claire L; Colbert, Sarah M C; Winiger, Evan A; Johnson, Emma C; Agrawal, Arpana; Bogdan, Ryan. (2021). Genetic Liability to Cannabis Use Disorder and COVID-19 Hospitalization.. Biological psychiatry global open science, 1(4), 317-323. https://doi.org/10.1016/j.bpsgos.2021.06.005