Zapata B · International journal of environmental research and public health 2021 · cross-sectional study · n=84

Omega-3 Index and Clinical Outcomes of Severe COVID-19: Preliminary Results of a Cross-Sectional Study.

Cited 30 times in the scientific literature.

Level 4 - case-series / case-control

Cross-sectional observational study with a small healthy control comparator

PubMed 34360016 · doi:10.3390/ijerph18157722 · record verified 2026-08-30

What was done

Researchers measured the Omega-3 Index (O3I), clinical variables, biometric indices, and nutritional information in 74 patients with severe COVID-19 and 10 healthy quality-control subjects. Associations between O3I levels and the requirements for mechanical ventilation or mortality were evaluated, adjusting for age, sex, and established risk factors.

What was found

Patients with severe COVID-19 had a mean O3I of 4.15% (range: 3.06–6.14%), lower than healthy controls (mean: 7.84%; range: 4.65–10.71%). After adjustment for sex, age, and risk factors, higher O3I was inversely associated with mechanical ventilation (OR = 0.459; 95% CI: 0.211–0.997) and death (OR = 0.28; 95% CI: 0.08–0.985).

Why it matters

These preliminary findings suggest circulating omega-3 fatty acid levels may be linked to adverse clinical trajectories in severe respiratory viral infections like COVID-19.

Limits

The study is limited by a small sample size (74 patients and 10 controls), a cross-sectional design that cannot determine causality, wide confidence intervals close to 1.0, and unmeasured confounding.

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