FEI-RAN GUO2021-02-042021-02-0420200146-6615https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084417675&doi=10.1002%2fjmv.25967&partnerID=40&md5=8c06bb69ba22133b1fafb071f14be013https://scholars.lib.ntu.edu.tw/handle/123456789/548427[SDGs]SDG3angiotensin converting enzyme 2; chronic obstructive lung disease; cigarette smoking; coronavirus disease 2019; disease association; disease severity; human; immune response; Letter; meta analysis (topic); odds ratio; receptor upregulation; scientific literature; sensitivity analysis; Severe acute respiratory syndrome coronavirus 2; statistical significance; systematic review (topic); chronic obstructive lung disease; severity of illness index; smoking; COVID-19; Humans; Pulmonary Disease, Chronic Obstructive; SARS-CoV-2; Severity of Illness Index; Smokingletter10.1002/jmv.25967323692032-s2.0-85084417675