The toxicity of E-cigarettes and children's respiratory health.

Electronic cigarettes (E-cig), also referred to as Electronic Nicotine Delivery System (ENDS), were initially developed in 2003 to reduce the harmful effects of tobacco smoking. Since then, E-cig have become widely available in many countries and are used by many young people who would be unlikely to take up cigarette smoking. However, the adverse effects on child health remain largely unknown. E-cigs are available through regulated sale in many countries, but easily accessible by the internet in others. Adverse effects may be ascribed to the nicotine itself, to the accompanying substances in the aerosol (often referred to as vapour) or to temperature modifications of the content. There is a lack of human studies to assess respiratory effects of nicotine exposure to the unborn or young child. Also assessing the effects of the vaping content apart from nicotine is challenging, with the huge variety of exposure by frequency, duration and content, but experimental studies are on the way that may indicate the level of harm by such products. This article will summarize what is currently known about the use of E-cigs in children and in pregnancy, and discuss adverse effects of direct or in utero exposure to E-cig on the respiratory health of children. We thereby hope to provide a background for discussing potential harms to the respiratory system of children by E-cig exposure in pregnancy and early post-natal life, in a setting where an increasing proportion of adolescent and young adults use E-cigs, marketed to be 95% less harmful than conventional cigarettes.