Corrigendum: Circulating polyunsaturated fatty acids and COVID-19: a prospective cohort study and Mendelian randomization analysis

[This corrects the article DOI: 10.3389/fmed.2022.923746.].

Circulating Polyunsaturated Fatty Acids and COVID-19: A Prospective Cohort Study and Mendelian Randomization Analysis

Higher circulating polyunsaturated fatty acids (PUFAs), especially omega-3 fatty acids, have been linked to a better prognosis in patients of coronavirus disease 2019 (COVID-19). However, the effects and causality of pre-infection PUFA levels remain unclear. This study aimed to investigate the observational and causal associations of circulating PUFAs with COVID-19 susceptibility and severity. We first performed a prospective cohort study in UK Biobank, with 20,626 controls who were tested negative and 4,101 COVID-19 patients, including 970 hospitalized ones. Plasma PUFAs at baseline (blood samples collected from 2007 to 2010) were measured by nuclear magnetic resonance, including total PUFAs, omega-3 PUFAs, omega-6 PUFAs, docosahexaenoic acid (DHA), linoleic acid (LA), and the omega-6/omega-3 ratio. Moreover, going beyond UK Biobank, we leveraged summary statistics from existing genome-wide association studies to perform bidirectional two-sample Mendelian randomization (MR) analyses to examine the causal associations of eight individual PUFAs, measured in either plasma or red blood cells, with COVID-19 susceptibility and severity. In the observational association analysis of each PUFA measure separately, total, omega-3, and omega-6 PUFAs, DHA, and LA were associated with a lower risk of severe COVID-19. Omega-3 PUFAs and DHA were also associated with a lower risk of testing positive for COVID-19. The omega-6/omega-3 ratio was positively associated with risks of both susceptibility and severity. When omega-6, omega-3, and their ratio are jointly analyzed, only omega-3 PUFAs remained significantly and inversely associated with both susceptibility and severity. The forward MR analysis indicated that docosapentaenoic acid (DPA-n3) and arachidonic acid (AA) might be causally associated with a lower risk of severe COVID-19, with OR (95% CI) per one SD increase in the plasma level as 0.89 (0.81, 0.99) and 0.96 (0.94, 0.99), respectively. The reverse MR analysis did not support any causal effect of COVID-19 on PUFAs. Our observational analysis supported that higher circulating omega-3 PUFAs, especially DHA, may lower the susceptibility to and alleviate the severity of COVID-19. Our MR analysis further supported causal associations of DPA-n3 and AA with a lower risk of severe COVID-19.

Circulating polyunsaturated fatty acids and COVID-19: a prospective cohort study and Mendelian randomization analysis

Background:

Higher circulating polyunsaturated fatty acids (PUFAs), especially omega-3 ones, have been linked to a better prognosis in patients of coronavirus disease 2019 (COVID-19). However, the effects and causality of pre-infection PUFA levels remain unclear.

Objective:

To investigate the observational and causal associations of circulating PUFAs with COVID-19 susceptibility and severity.

Design:

We first performed a prospective cohort study in UK Biobank, with 20,626 controls who were tested negative and 4,101 COVID-19 patients, including 970 hospitalized ones. Plasma PUFAs at baseline were measured by nuclear magnetic resonance, including total PUFAs, omega-3 PUFAs, omega-6 PUFAs, docosahexaenoic acid (DHA), linoleic acid (LA), and the omega-6/omega-3 ratio. Moreover, bidirectional two-sample Mendelian randomization (MR) analyses were performed to examine the causal associations of eight individual PUFAs, measured in either plasma or red blood cells, with COVID-19 susceptibility and severity using summary statistics from existing genome-wide association studies.

Results:

In the observational association analysis, total PUFAs, omega-3 PUFAs, omega-6 PUFAs, DHA, and LA were associated with a lower risk of severe COVID-19. Omega-3 PUFAs and DHA were also associated with a lower risk of testing positive for COVID-19. The omega-6/omega-3 ratio was positively associated with risks of both susceptibility and severity. The forward MR analysis indicated that arachidonic acid (AA) and docosapentaenoic acid (DPA-n3) might be causally associated with a lower risk of severe COVID-19, with OR (95% CI) per one SD increase in the plasma level as 0.96 (0.94, 0.99) and 0.89 (0.81, 0.99), respectively. The reverse MR analysis did not support any causal effect of COVID-19 on PUFAs.

Conclusions:

Our observational analysis supported that higher circulating PUFAs, either omega-3 or omega-6, are protective against severe COVID-19, while omega-3 PUFAs, especially DHA, were also associated with reducing COVID-19 susceptibility. Our MR analysis further supported causal associations of AA and DPA-n3 with a lower risk of severe COVID-19.

Red Blood Cell Polyunsaturated Fatty Acids and Vascular Diseases: A Mendelian Randomization Study

Objectives

To evaluate the causal association of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs), as measured in red blood cells (RBC), with cardiovascular disease (CVD), cerebrovascular disease (CBVD), and peripheral vascular disease (PVD).

Methods

Applying a two-sample Mendelian Randomization approach, we first developed genetic instruments for RBC-PUFAs by utilizing summary statistics from previous genome-wide association study in the Framingham Heart Study. We then evaluated the association of these instrumental variables with CVD, CBVD, PVD, and their subtypes in the UK Biobank cohort.

Results

Strong evidence of causal association with at least one RBC-PUFAs was observed for the overall risk of PVD and three of its subtypes (aortic aneurysm and dissection, arterial embolism and thrombosis, and other PVDs), but only for two CVD subtypes (hypertensive heart disease, and chronic ischemic heart disease) and for two CBVD subtypes (stroke, and cerebral infarction). Based on their effects on all examined diseases, RBC-PUFAs clustered into two groups: a protective group with alpha-Linolenic acid (ALA), linoleic acid (LA), eicosadienoic acid (EDA), and dihomo-gamma-linolenic acid (DGLA); and the other risk group with docosapentaenoic acid (DPA), gamma-linolenic acid (GLA), arachidonic acid (AA), and adrenic acid (AdrA). PUFAs in the protective group are protective, while those in the risk group are risk-increasing, for all diseases with significant associations except for hypertensive heart diseases. In the metabolic pathway converting short-chain PUFAs into long-chain ones, the protective group is mapped to precursors of desaturases, while the risk group corresponds to their products.

Conclusions

Genetically regulated RBC-PUFAs are associated with the risk of PVD, and subtypes of PVD, CVD, and CBVD.

Funding Sources

University of Georgia Research Foundation.