Internal medicine

Biology

Gene

Genotype

Transferrin saturation

Odds ratio

Ferritin

Sepsis

Mendelian randomization

Genetic variants

Serum ferritin

Confidence interval

Genetics

Medicine

Scientific Reports

Observational studies have indicated an association between iron status and risk of sepsis and COVID-19. We estimated the effect of genetically-predicted iron biomarkers on risk of sepsis and risk of being hospitalized with COVID-19, performing a two-sample Mendelian randomization study. For risk of sepsis, one standard deviation increase in genetically-predicted serum iron was associated with odds ratio (OR) of 1.14 (95% confidence interval [CI] 1.01–1.29, P = 0.031). The findings were supported in the analyses for transferrin saturation and total iron binding capacity, while the estimate for ferritin was inconclusive. We found a tendency of higher risk of hospitalization with COVID-19 for serum iron; OR 1.29 (CI 0.97–1.72, P = 0.08), whereas sex-stratified analyses showed OR 1.63 (CI 0.94–2.86, P = 0.09) for women and OR 1.21 (CI 0.92–1.62, P = 0.17) for men. Sensitivity analyses supported the main findings and did not suggest bias due to pleiotropy. Our findings suggest a causal effect of genetically-predicted higher iron status and risk of hospitalization due to sepsis and indications of an increased risk of being hospitalized with COVID-19. These findings warrant further studies to assess iron status in relation to severe infections, including the potential of improved management.

Iron status and the risk of sepsis and severe COVID-19: a two-sample Mendelian randomization study