Surgical removal of tonsils and risk of COVID-19: a nested case–control study using data from UK Biobank and AMORIS Cohort – BMC Medicine
Background To investigate the association between surgical removal of tonsils and risk of COVID-19 with different severity. Methods Through a nested case–control study during January 31st to December 31st 2020, including 58,888 participants of the UK Biobank, we investigated the association of tonsillectomy with the future risk of mild and severe COVID-19, using binomial logistic regression. We further examined the associations of such surgery with blood inflammatory, lipid and metabolic biomarkers to understand potential mechanisms. Finally, we replicated the analysis of severe COVID-19 in the Swedish AMORIS Cohort (n = 451,960). Results Tonsillectomy was associated with a lower risk of mild (odds ratio [95% confidence interval]: 0.80 [0.75–0.86]) and severe (0.87 [0.77–0.98]) COVID-19 in the UK Biobank. The associations did not differ substantially by sex, age, Townsend deprivation index, or polygenic risk score for critically ill COVID-19. Levels of blood inflammatory, lipid and met
