Sin S, Lee CH, Choi SM, et al. - Metabolic syndrome is known to raise the risk of several cancers, so researchers examined the effect of metabolic syndrome on lung cancer incidence. This research engaged participants from January 2009 to December 2012 in a health screening program supported by the Korean National Health Insurance Service. Lung cancer incidence was observed until December 2016. Out of 9,586,753 participants, there were 45,635 new cases of lung cancer reported during the study. Findings suggested an association of metabolic syndrome with an increased risk of lung cancer in males. In addition, the greater the number of components of metabolic syndrome, the higher the risk of lung cancer. Underweight ever-smoker males may experience a greater effect of metabolic syndrome on the increased risk of lung cancer vs other candidates.