Diet quality and risk and severity of COVID-19: a prospective cohort study

Merino, J.; Joshi, A. D.; Nguyen, L.; Leeming, E.; Drew, D. A.; Gibson, R.; Graham, M. S.; Mazidi, M.; Lo, C.-H.; Capdevila, J.; Murray, B.; hu, c.; Selvachandran, S.; Kwon, S.; MA, W.; Menni, C.; Hammers, A.; Bhupathiraju, S.; Sharma, S.; Sudre, C.; Astley, C. M.; Willett, W.; Chavarro, J.; Ourselin, S.; Steves, C.; Wolf, J.; Franks, P. W.; Spector, T.; Berry, S.; Chan, A. T.

Objective: Poor metabolic health and certain lifestyle factors have been associated with risk and severity of coronavirus disease 2019 (COVID-19), but data for diet are lacking. We aimed to investigate the association of diet quality with risk and severity of COVID-19 and its intersection with socioeconomic deprivation. Design: We used data from 592,571 participants of the smartphone-based COVID Symptom Study. Diet quality was assessed using a healthful plant-based diet score, which emphasizes healthy plant foods such as fruits or vegetables. Multivariable Cox models were fitted to calculate hazard ratios (HR) and 95% confidence intervals (95% CI) for COVID-19 risk and severity defined using a validated symptom-based algorithm or hospitalization with oxygen support, respectively. Results: Over 3,886,274 person-months of follow-up, 31,815 COVID-19 cases were documented. Compared with individuals in the lowest quartile of the diet score, high diet quality was associated with lower risk of COVID-19 (HR, 0.91; 95% CI, 0.88-0.94) and severe COVID-19 (HR, 0.59; 95% CI, 0.47-0.74). The joint association of low diet quality and increased deprivation on COVID-19 risk was higher than the sum of the risk associated with each factor alone (Pinteraction=0.005). The corresponding absolute excess rate for lowest vs highest quartile of diet score was 22.5 (95% CI, 18.8-26.3) and 40.8 (95% CI, 31.7-49.8; 10,000 person-months) among persons living in areas with low and high deprivation, respectively. Conclusions: A dietary pattern characterized by healthy plant-based foods was associated with lower risk and severity of COVID-19. These association may be particularly evident among individuals living in areas with higher socioeconomic deprivation.