Cannabis use and obesity-traits: A Mendelian randomization study

Area of Science:

• Genetics
• Epidemiology
• Metabolic Health

Background:

• Observational studies suggest a link between cannabis use and reduced body fatness.
• Confounding factors in observational studies make causal inference difficult.
• Mendelian randomization (MR) can help establish causality by using genetic variants as instrumental variables.

Purpose of the Study:

• To investigate the potential causal association between cannabis use and obesity-related traits using Mendelian randomization.
• To determine if genetic predisposition to cannabis use influences body mass index (BMI), waist circumference (WC), and waist-hip ratio (WHR).

Main Methods:

• Utilized summary statistics from large-scale genome-wide association studies (GWAS).
• Employed 51 single nucleotide polymorphisms (SNPs) for lifetime cannabis use and 27 SNPs for cannabis use disorder as instrumental variables.
• Analyzed GWAS data for BMI, WC, and WHR from European descent populations.

Main Results:

• Mendelian randomization analysis revealed no statistically significant causal association between lifetime cannabis use or cannabis use disorder and BMI.
• No causal association was found between cannabis use indicators and waist circumference or waist-waist hip ratio.
• Sensitivity analyses, including leave-one-out and pleiotropy-robust methods, did not indicate bias in the estimates.

Conclusions:

• The Mendelian randomization study provides limited evidence for a causal influence of cannabis use on obesity-related traits.
• Findings suggest that genetic factors associated with cannabis use do not appear to causally affect body fatness or obesity indicators.