Lee HS, et al. - Via involving 882 patients with ulcerative colitis (UC) and 3091 healthy controls, researchers studied the impacts of smoking on the relationship between human leukocyte antigen (HLA) and UC. Using a case-control approach, smoking-stratified analyses of HLA data were performed. According to findings, an association was limited to never smokers between UC and HLA-DRB1*15:02. The study findings point out that tobacco smoking alters the effects of HLA on UC's risk.