The threat of vaping in youths.

Electronic cigarettes are driving a new epidemic of nicotine dependence among youths and are now the dominant tobacco product used by adolescents in the United States and other countries. Candy and fruit flavorings have driven their use, and many products contain higher nicotine concentrations, which contributed to their addictive potential. Numerous epidemiologic studies have described increased rates of respiratory symptoms in adolescent electronic cigarette users, and in vitro and in vivo studies showed that electronic cigarette vapors exert extensive biological effects on human airways, different from tobacco smoke, leading to epithelial cell dysregulation, inflammation, mucus hypersecretion, and apoptosis. Severe acute lung injury has been reported in adolescents and young adults, particularly in those using tetrahydrocannabinol (THC)-containing products, underscoring the threats of electronic cigarettes to lung health.