PURPOSE OF THE STUDY.
Recent evidence indicates that the susceptibility to the adverse effects of air pollution is greater in the lower socioeconomic population. This may be as a result of increased psychosocial stress. This study hypothesized that psychosocial stress modifies the effect of traffic exposure on lung function.
Studied were 1399 children in the Southern California Children’s Health Study who were undergoing lung function testing. The study population came from 8 communities in southern California; these communities were selected to reflect a broad range of regional air pollutant exposures and large gradients in traffic exposure within communities.
All children involved in the study underwent spirometric lung function testing during the 2008–2009 school year. Information regarding respiratory illnesses and environmental exposures was collected via a questionnaire. Sociodemographic characteristics (ie, race, income, insurance, tobacco smoke exposure) were assessed via a questionnaire at time of enrollment into the study in 2002–2003. The perceived stress scale, a 4-item questionnaire, was used to measure parental stress at time of enrollment. Exposure to nitric oxide, nitrogen dioxide, and total oxides of nitrogen (NOx) were estimated by using measurements of these pollutants at 940 locations in the studied communities over a 2-week period.
Among children in high-stress households (perceived stress scale >4), flow in the large airways (forced expiratory volume 1 [FEV1]) decreased by 4.5% and 2.8% for each 21.8 ppb increase in NOx at homes and schools, respectively. Pollutant effects were significantly larger in the high-stress households compared with lower-stress households (P = .007 for residential NOx, P = .05 for school NOx). Similar results were observed for lung function volume (forced vital capacity [FVC]). These associations remained after adjustment for sociodemographic factors and in an analysis restricted to children who do not have asthma.
Results suggest that a high-stress environment in the home, as determined by parental perceived stress, is associated with increased susceptibility to lung function effects of air pollution at home and school.
Evidence has shown an association between exposure to air pollution and an increase in asthma prevalence, exacerbation rate, and lung function deficits. Additionally, psychosocial stress is associated with increased endogenous steroid production, leading to steroid resistance and diminished anti-inflammatory effect of cortisol. This study examined the detrimental effects of both, with results suggesting that children with high psychosocial stress in the home are more susceptible to the known health effects caused by air pollution. Furthermore, this study evaluated patients both with and without asthma, and showed consistent results in all children with traffic-related air pollution exposure. Those whose parents reported a stressful life during the child’s early school age experienced damaging effects in both FVC and FEV1. Further studies with longitudinal measurement of parental stress, personal stress, and lung function measurement are needed to evaluate this possible association.
- Copyright © 2012 by the American Academy of Pediatrics