Genetically Determined Circulating Saturated and Unsaturated Fatty Acids and the Occurrence and Exacerbation of Chronic Obstructive Pulmonary Disease—A Two-Sample Mendelian Randomization Study

Research on dietary fatty acids (FAs) and lung health has reported skeptical findings. This study aims to examine the causal relationship between circulating FAs and Chronic Obstructive Pulmonary Disease (COPD) onset and exacerbation, using a two-sample Mendelian Randomization (MR) analysis. Strong and independent genetic variants of FAs were obtained from the UK Biobank of European ancestry. The exposure traits included saturated FA (SFA), poly- and mono-unsaturated FA (PUFA and MUFA), omega-3 and omega-6 PUFA, docosahexaenoic acid (DHA), and linoleic acid (LA), all expressed as total FA (TFA) percentages. Summary statistics for COPD outcomes were obtained from the FinnGen consortium including COPD, COPD hospitalization, COPD/asthma-related infections, COPD-related respiratory insufficiency, and COPD/asthma/interstitial lung disease (ILD)-related pneumonia. The inverse-variance weighted (IVW) was the primary MR approach. MR-Egger regression and MR-PRESSO were utilized to evaluate heterogeneity and pleiotropy. MR-PRESSO tests suggested no obvious horizontal pleiotropy. MR results by the IVW approach indicated that the genetically high SFA/TFA levels were associated with an increased risk of COPD/asthma/ILD-related pneumonia (OR: 1.275, 95%CI: 1.103–1.474, p for FDR = 0.002). No significant relationship was observed between other types of FAs and COPD outcomes. Our MR analysis suggests that there is weak evidence that the genetically predicted high SFA/TFA was associated with an increased risk of pneumonia.