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Associations between the Dietary Inflammatory Index and COVID-19 Outcomes in the UK Biobank Cohort
24 Pages Posted: 14 Dec 2022More...
Background: COVID-19 is characterized by dysfunction in the inflammatory and immune response systems. We hypothesize that diet, the most important modulator of inflammatory and immune response, may affect COVID-19 incidence and disease severity.
Methods: We used data from a population-based prospective cohort study, the UK biobank, in which 196,154 participants had at least one 24-hour dietary Oxford Web Questionnaire recall. COVID-19 outcomes were derived from PCR testing data, hospital admissions data, and death certificates. An adjusted Poisson regression analysis was performed to estimate the risk ratios (RR) and their 95% confidence intervals (CI) for dietary inflammatory index (DII)/energy-adjusted DII (E-DII) scores as continuous variables and as quintiles. Models were adjusted for sociodemographic factors, comorbidities, smoking status, physical activity, and sleep duration.
Findings: Between January 2020 and March 2021, there were 11,288 incident cases of COVID-19, 1270 COVID-19-related hospitalizations, and 315 COVID-19-related deaths. Results from the fully adjusted model showed that participants in the highest (vs. lowest) quintile of DII were at increased risk of COVID-19 (RRQ5vsQ1=1·17, 95%CI 1·10-1·24, Ptrend<0·001 for E-DII vs RRQ5vsQ1=1·10, 95%CI 1·02-1·14, Ptrend=0·001 for DII). Stronger associations were observed for the severity of COVID-19 (DII: RRQ5vsQ1RR=1·40, 95%CI 1·18-1·67, Ptrend<0·001; E-DII: RRQ5vsQ1=1·39, 95%CI 1·16-1·66, Ptrend<0·001). For COVID-19-related death, a positive association was observed for DII (RRQ5vsQ1=1·43, 95%CI 1·01-2·01, Ptrend=0·04), but was not for E-DII (RRQ5vsQ1=1·32, 95%CI 0·92-1·89, Ptrend=0·30). About ¼ of the observed positive associations between DII and COVID-19-related outcomes were mediated by body mass index (25·8% for incidence, 21·6% for severity, and 19·8% for death).
Interpretation: Diet-associated inflammation increased the risk of COVID-19 infection and of severe COVID-19 disease. Future work should include replicating these results in other cohorts and designing and implementing inflammation-lowering dietary intervention trials to reduce the incidence and severity of COVID-19 and other respiratory infections.
Funding Information: This work was conducted without external financial support.
Declaration of Interests: The authors declare that they have no competing interests.
Ethics Approval Statement: NA
Keywords: DII, COVID-19, cohort, nutrition, inflammation
Suggested Citation: Suggested Citation