Passive smoking in children and allergic risk

Exposure to second-hand tobacco smoke (SHS) and nicotine during the prenatal and post-natal periods can impair lung development and immune response, and can increase the prevalence of wheezing during childhood. Exposed neonates are at greater risk for diminished lung function and increased asthma symptoms throughout childhood. Recently, genomic and epigenetic risk factors, such as impaired DNA methylation, have been identified that may affect the risk of long-term disease. In addition, this review examines the role of SHS during the prenatal and post-natal periods and its association with increased risk of infection, skewing of the immune response toward a T-helper type 2 bias, and increasing the risk of developing an allergic phenotype and asthma-like symptoms during childhood. Passive smoking may also contribute to the development of food hypersensitivity via progression of the atopic march since SHS is a known risk factor for asthma and eczema. Smoking during pregnancy is the most common preventable cause of infant morbidity and mortality. There is an increasing body of evidence showing that children also reap health benefits following the introduction of legislation to restrict smoking in public places. (C) 2020 Elsevier Masson SAS. All rights reserved.