The association between adherence to unhealthy plant-based diet and risk of COVID-19: a cross-sectional study

Background: The fast spread of the coronavirus disease 2019 (COVID-19) epidemic and its high mortality were quickly considered by the health community. Dietary patterns play an important role in strengthening or weakening the immune system and thus incidence of diseases.

Aim: The present study can provide a comprehensive picture of the association between adherence to unhealthy plant-based diet (uPDI) and COVID-19 incidence.

Methods: This study was undertaken on 8157 adults' participants of the Yazd Health Study (YaHS) and Taghzieh Mardom-e-Yazd (TAMIZ) study aged 20 to 70 years. Data on dietary intakes were obtained using a validated food frequency questionnaire (FFQ). Multivariable logistic regression analysis was used to assess the association between uPDI and COVID-19.

Results: We found a significant association between uPDI and the risk of COVID-19 (OR: 1.36; 95% CI: 1.05-1.75) in the crude model. After adjusting potential confounders, a significant increasing trend in the odds of COVID-19 across increasing quintiles of uPDI (OR: 1.58;95% CI: 1.05-2.37; P-value: 0.027) was observed. Stratified analysis based on sex indicated that uPDI significantly increased the risk of COVID-19 only in males (OR: 1.73;95% CI: 1.12-2.67; P-value: 0.012) and had no effect on females.

Conclusions: Participants in the highest quintiles of the uPDI had 58% higher odds of COVID-19 compared to subjects in the lowest quintile of uPDI. Although our study has promising results, stronger clinical studies are needed.