Sex difference and smoking predisposition in patients with COVID-19

Best Practice Nordic | Maalis 2020 | COVID-19 |

Studies have shown a higher prevalence of severe disease progression with COVID-19 among men - especially Asian men - than in women and in patients of other ethnicities. Furthermore, smokers seem generally more prone to the serious complications of COVID-19 infection, but there is not strong evidence. No firm conclusions can therefore be drawn about association between smoking and prevalence or severity of COVID-19 in Asian men compared with other subgroups. The outbreak of the novel coronavirus disease 2019 (COVID-19) has  quickly turned  into a pandemic. Studies on the biology of viral infection and clinical management of the disease have been published, some of which have demonstrated that differences in COVID-19 disease prevalence and severity are associated with sex, and smoking because of a higher expression of ACE2 (the receptor for severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]). One study,1 using single-cell sequencing, found that expression of ACE2 was more predominant in Asian men, which might be the reason for the higher prevalence of COVID-19 in this subgroup of patients than in women and patients of other ethnicities. One study of 140 patients with COVID-19 in China, found the sex distribution equal, whereas, in a study of critically ill patients,3 more men were affected (67%) than women. In a latest report4 of 1099 patients with COVID-19 from 552 hospitals in 30 provinces in China, 58% of the patients were men. Taken together, these data seem to indicate that there might be a sex predisposition to COVID-19, with men more prone to being affected. This sex predisposition might be associated with the much higher smoking rate in men than in women in China, where 288 million men vs 12.6 million women were smokers in 2018. One study5  found that although ACE2 expression was not significantly different between Asian and white people,...