Background: Birth defects are a leading cause of neonatal mortality. Natural gas development (NGD) emits several potential teratogens and US production is expanding.
Objectives: We examined associations between maternal residential proximity to NGD and birth outcomes in a retrospective cohort study of 124,842 births between 1996 and 2009 in rural Colorado.
Methods: We calculated inverse distance weighted natural gas well counts within a 10-mile radius of maternal residence to estimate maternal exposure to NGD. Logistic regression, adjusted for maternal and infant covariates, was used to estimate associations with exposure tertiles for congenital heart defects (CHDs), neural tube defects (NTDs), oral clefts, preterm birth, and term low birth weight. The Association with term birth weight was investigated using multiple linear regression.
Results: Prevalence of CHDs increased with exposure tertile, with an odds ratio (OR) of 1.3 for the highest tertile (95% CI: 1.2, 1.5) and NTD prevalence was associated with the highest tertile of exposure (OR = 2.0, 95% CI: 1.0, 3.9, based on 59 cases), compared to no gas wells within a 10-mile radius. Exposure was negatively associated with preterm birth and positively associated with fetal growth, though the magnitude of association was small. No association was found between exposure and oral clefts.
Conclusions: In this large cohort, we observed an association between density and proximity of natural gas wells within a 10-mile radius of maternal residence and prevalence of CHDs and possibly NTDs. Greater specificity in exposure estimates are needed to further explore these associations.
PURPOSE OF REVIEW: Studies over the last 2 years have added important new information on the relationship between air pollution and asthma incidence and severity.
RECENT FINDINGS: Outdoor air pollution has been associated with asthma exacerbations, including emergency department visits and hospitalizations, as well as with the onset of asthma. Possible mechanisms mediating both incidence and severity effects include the induction of oxidative stress, and/or allergic sensitization, as well as increased susceptibility to viral infections. Some of these mechanisms may be occurring in utero including epigenetic changes that may increase risk for development of asthma. Factors related to increased susceptibility for air pollution-related asthma severity include age, season and genetic polymorphisms related to antioxidant enzymes.
SUMMARY: Ambient pollution levels may be associated with both asthma incidence and severity. Susceptibility to air pollution may be higher in children with genetic polymorphisms related to the ‘oxidant stress pathways’. Potential interventions for susceptible children at risk for asthma development and/or severity include decreased exposure on high air pollution days, especially in the summer months, and antioxidant supplementation. On the population level, changes in school and home zoning to increase distance from busy roadways may help reduce both asthma incidence and severity.
A 2002 analysis documented $54.9 billion in annual costs of environmentally mediated diseases in US children. However, few important changes in federal policy have been implemented to prevent exposures to toxic chemicals. We therefore updated and expanded the previous analysis and found that the costs of lead poisoning, prenatal methylmercury exposure, childhood cancer, asthma, intellectual disability, autism, and attention deficit hyperactivity disorder were $76.6 billion in 2008. To prevent further increases in these costs, efforts are needed to institute premarket testing of new chemicals; conduct toxicity testing on chemicals already in use; reduce lead-based paint hazards; and curb mercury emissions from coal-fired power plants.