The effects of second-hand and direct exposure to tobacco smoke on asthma and lung function in adolescence.

Cigarette smoking still is quite common in many parts of the world. In parallel, exposure to second-hand smoke continues to be common despite declines in smoking in developed countries and despite evidence of serious health effects in infants and children. This paper focuses on the effects of second-hand and direct exposure (personal smoking) on the respiratory health of adolescents, in particular effects on the occurrence of asthma and on lung function. Published data indicate that, in addition to whatever effects direct and postnatal second-hand tobacco smoke exposure have on the occurrence of asthma and impaired levels and growth of lung function in adolescents, there is an underlying alteration in the prenatal and early postnatal development of the structural and mechanical characteristics of the lung that contribute substantially to these deficits. These developmental effects may be important contributors to the future risks for impaired pulmonary function.