Sin S, Lee CH, Choi SM, et al. - Researchers investigated how the incidence of lung cancer is influenced by metabolic syndrome. For this purpose, participants in a health screening program offered by the Korean National Health Insurance Service between January 2009 and December 2012 were enrolled. Until December 2016, lung cancer incidence was evaluated. The presence of metabolic syndrome, metabolic syndrome components, and number of metabolic syndrome components were evaluated with regard to lung cancer risk. There were 9,586,753 participants in total. Among these, 45,635 new cases of lung cancer were documented during the study. According to the findings, an increased risk of lung cancer in men was observed in relation to the presence of metabolic syndrome. Lung cancer risk rose with the number of components present. Relative to other participants, underweight male ever smokers possibly were more susceptible to the effect of metabolic syndrome on the increasing risk of lung cancer.