Published Online: November 8, 2013
While the spectrum of childhood wheeze phenotypes is complex, an important step in identifying children who are at risk for chronic respiratory problems is to characterize the risk factors that lead to and maintain this early predisposition, likely starting before birth. Recent work suggests that the increased risk of wheezing respiratory illnesses in lower socioeconomic status (SES) urban communities may be related to differential environmental exposures, including social stressors (such as neighborhood violence) and physical toxins (such as traffic-related air pollution), although this had not been studied directly.
Recently in The Journal of Allergy & Clinical Immunology (JACI), Chiu et al. conducted analyses in a lower-SES urban sample of women recruited in pregnancy and followed their children after birth to age 2 years. They found that children born to mothers reporting higher exposure to crime and violence in their communities during pregnancy were about twice as likely to have repeated episodes of wheeze during the follow-up period compared with those born to mothers reporting lowest exposure. Notably, this association was independent of a relationship of similar magnitude seen between prenatal exposure to traffic-related pollutants and repeated wheeze in these children – the odds were twice as likely of having a child with recurrent wheeze among mothers exposed to higher level of air pollution when compared to women with lower exposure. They observed these associations even after accounting for a number of child factors (i.e., gender, season of birth, birth weight) and maternal factors (i.e., race, education, obesity, atopic history), as well as other environmental factors (i.e., cockroach allergen in the home, smoking).
These findings further support the notion that an adverse psychosocial environment is not simply a surrogate marker of an adverse physical environment in the urban setting with respect to children’s respiratory health. Research that considers psychosocial stress, including that experienced in their neighborhoods, together with physical environmental toxins concurrently, may better inform the etiology of respiratory health disparities, especially given that these factors tend to cluster in the most socially disadvantaged communities in the United States. While we need to continue working towards public health solutions to reduce residents' exposure to crime and violence as well as traffic pollution in urban neighborhoods, clinicians should also be talking to pregnant women about ways to reduce their exposure to stress in their lives and communities just as they council them to minimize exposure to physical pollutants that may impact their infants' respiratory health, like tobacco smoke and outdoor air pollution.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.