DOI record: { "DOI": "10.3389/fnut.2026.1892752", "ISSN": [ "2296-861X" ], "URL": "http://dx.doi.org/10.3389/fnut.2026.1892752", "abstract": "<jats:sec>\n <jats:title>Background and aims</jats:title>\n <jats:p>Long-chain omega-3 fatty acids (FAs) and vitamin D (VitD) are implicated in the modulation of immune responses and inflammatory processes within the body. The COMED study evaluated levels of DHA, EPA and DPA (expressed as a modified omega-3 index, mO3I, defined as the percentage of these FAs relative to total FAs in whole blood) and VitD in patients with COVID-19 in relation to mortality and severe disease, as well as additional morbidity-related outcomes, including probability of hospitalisation and length of hospital stay (LOS).</jats:p>\n </jats:sec>\n <jats:sec>\n <jats:title>Methods</jats:title>\n <jats:p>A total of 160 patients were enrolled, of whom 28 died during follow-up. Associations between mO3I and VitD levels and clinical outcomes were analysed using logistic and linear regression models adjusted for age, sex, BMI, smoking, diabetes mellitus, and hypertension.</jats:p>\n </jats:sec>\n <jats:sec>\n <jats:title>Results</jats:title>\n <jats:p>Higher mO3I levels (Q4 ≥ 6.39%) were associated with lower odds of death (OR = 0.24, 95% CI: 0.05–0.87) and lower probability of hospitalisation (OR = 0.28, 95% CI: 0.09–0.91) compared with lower mO3I levels (Q1–Q3). Higher VitD levels (Q4 ≥ 71.9 nmol/L) were associated with a shorter LOS by 2.19 days compared with Q1–Q3, while higher levels (Q2–Q4 &amp;gt; 36.7 nmol/L) shortened LOS by 2.96 days compared with Q1. Age was the strongest predictor of mortality, severe disease, and LOS; BMI increased the probability of severe disease; smoking prolonged LOS.</jats:p>\n </jats:sec>\n <jats:sec>\n <jats:title>Conclusion</jats:title>\n <jats:p>Higher mO3I levels were associated with lower odds of death, with similar trends observed for hospitalisation, whereas higher VitD levels were associated with a shorter LOS. Nutritional biomarkers and modifiable lifestyle factors, such as body weight and smoking, were associated with differences in clinical outcomes in COVID-19. 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