Mendelian Randomization Study of Causal Relationship between Omega-3 Fatty Acids and Risk of Lung Cancer

Area of Science:

• Nutritional Epidemiology
• Genetic Epidemiology
• Oncology

Background:

• Omega-3 fatty acid intake is suggested to protect against lung cancer.
• The causal relationship between omega-3 fatty acids and lung cancer risk remains unclear.
• Genome-wide association study (GWAS) data and Mendelian randomization (MR) can investigate causal effects.

Purpose of the Study:

• To clarify the causal effect of omega-3 fatty acids on lung cancer risk.
• To utilize a Mendelian randomization approach with GWAS data.
• To determine if omega-3 fatty acids are protective against lung cancer.

Main Methods:

• Acquired omega-3 fatty acid and lung cancer data from UK Biobank and ILCCO.
• Selected single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for omega-3 fatty acids.
• Employed inverse variance weighted (IVW), MR-Egger, weighted median, and other MR methods to assess causality.
• Assessed heterogeneity and pleiotropy using Cochran's Q test and MR-Egger regression.

Main Results:

• Identified 42 SNPs associated with omega-3 fatty acids as IVs.
• Multiple MR analyses (IVW, MR-Egger, weighted median, weighted mode) indicated a causal association between omega-3 fatty acids and reduced lung cancer risk.
• No significant genetic or horizontal pleiotropy was detected.

Conclusions:

• Omega-3 fatty acids act as causal protective factors for lung cancer.
• The findings provide strong evidence for the role of omega-3s in lung cancer prevention.
• Further research is needed to elucidate the underlying biological mechanisms.