Association between Blood N-3 Fatty Acid Levels and Risk for COVID-19 in the UK biobank

Background The role of nutritional status and risk for contracting and/or suffering adverse outcomes from SARS-CoV-2 infection is unclear. Preliminary studies suggest that higher n-3 PUFA intakes may be protective. Objectives The purpose of this study was to compare risk for three COVID-19 outcomes (testing positive for SARS-CoV-2, hospitalization, and death) as a function of baseline plasma DHA levels. Methods DHA levels (% of total fatty acids) were measured by nuclear magnetic resonance. The three outcomes and relevant covariates were available for 110,584 subjects (hospitalization and death) and for 26,595 ever-tested subjects (positive for SARS-CoV-2) in the UK Biobank prospective cohort study. Outcome data between January 1, 2020 and March 23, 2021 were included. Omega-3 Index (red blood cell EPA+DHA%) values across DHA% quintiles were estimated. Multi-variable Cox-proportional hazards models were constructed and linear (per 1-SD) relations with risk for each outcome were computed as hazard ratios (HRs). Results In the fully adjusted models, comparing the fifth to the first DHA% quintiles, the HR for testing positive (95% CI) was 0.79 (0.71, 0.89; p<0.001), for being hospitalized was 0.74 (0.58, 0.94; P<0.05), and for dying with COVID-19 was 1.04 (0.69, 1.57; NS). On a per 1-SD increase in DHA% basis, the HRs were: for testing positive, 0.92 (0.89,0.96; p<0.001); for hospitalization, 0.89 (0.83, 0.97; p<0.01); and for death, 0.95 (0.83,1.09). Estimated Omega-3 Index values across DHA quintiles ranged from 3.5% (quintile 1) to 8% (quintile 5). Conclusions These findings suggest that nutritional strategies to increase circulating n-3 PUFA levels, such as increased consumption of oily fish and/or use of n-3 fatty acid supplements, may reduce risk for adverse COVID-19 outcomes.