Premature infants: the impact of environmental stimuli on lung development in early life

Abstract

exposure assessment on particulate matter (Han X, 2006), several respiratory outcomes have been associated with air pollution exposure in children. Since lung development continues through adolescence and because of higher minute ventilation and higher levels of physical activity, children are more vulnerable to the adverse effects of air pollution than are adults. The respiratory effects of air pollution can be divided into three major areas: respiratory symptomatology and disease, pulmonary function and airway reactivity. Some contaminants (e.g., benzene, carbon dioxide, carbon monoxide, lead, nitrogen oxide, particulate matter and sulfur dioxide) can cause cancer, birth defects, brain and nerve damage and long term injury to the lungs and airway passages. When certain concentrations and durations are exceeded, these can cause severe injury and even death. Respiratory symptoms associated with air pollution exposure in children include burning eyes and nose, recurrent colds, itchy irritated throat, chronic cough and difficulty breathing. Also noted is increased prevalence of chest wheezing apart from colds or of wheezing most days or nights, of chest tightness, and of cough/phlegm production requiring medical attention. Air pollution is also associated with increased incidence of chest illness and of acute upper and lower respiratory tract infections. Furthermore, increased frequency of symptomatic asthmatic attacks, of exacerbations in persons with chronic cardiopulmonary or other disease, of emergency ward or physician visits, and increased frequency and duration of hospitalization for respiratory conditions have been observed. A meta-analysis showed 1.8 times risk of pneumonia in young children due to exposure to unprocessed solid fuel (Dherani M, 2008). Reductions in pulmonary function such as FEV1 or FVC associated with clinical symptoms have been reported with air pollution. Children may fail to maintain their predicted FEV1 growth curve. Further associations include increase in use of asthma medication and enhanced bronchial reactivity (AAP, 2004; ATS, 2000; Ackermann-Liebrich U, 1992; Braun-Fahrlander C,