Parental smoking: asthma and wheezing illnesses in infants and children.

Parental smoking has an important impact on asthma and wheezing illnesses in infants and children. In utero exposure is associated with impaired lung growth and wheezing illnesses, particularly in preschool children. Exposure to environmental tobacco smoke is associated with increased wheezing illnesses and increased symptoms in asthmatics. There are no consistent data to confirm an effect of in utero or postnatal cigarette smoke exposure on the prevalence of asthma but there is evidence of increased severity of symptoms. The detrimental effects of parental smoking on lung growth will have an impact on respiratory health throughout life.