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Asthma in boys linked to maternal prenatal stress, air pollution

Male infants who were exposed to ambient fine particulate matter and maternal psychosocial stress in utero were more likely to develop asthma by 6 years of age, according to research presented at the 2017 American Thoracic Society International Conference.

“We know from prior research that air pollution affects childhood lung health starting in early development, even in pregnancy,” Alison Lee, MD, MS, from the Icahn School of Medicine at Mount Sinai, told Infectious Diseases in Children. “Our study suggests that children, especially boys, born to women experiencing increased levels of stress during pregnancy may be even more sensitive to the negative effects of air pollution.”

Alison Lee

To evaluate the connection between ambient fine particulate matter (PM_2.5) and asthma in early childhood regarding potential additional effects of maternal stress and the sex of the infant, the researchers conducted an analysis of 736 mothers and their full-term infants. Each infant was born at least 37 weeks gestational age and were followed until they reached 6 years of age to observe if a physician had provided an asthma diagnosis.

Using a validated satellite-based spatiotemporal resolved model, the researchers estimated daily maternal PM_2.5 over the length of gestation. Additionally, negative life events scores were collected, with mothers acquiring a score of three or more considered to have high stress. The researchers also used Bayesian distributed lag interaction models to adjust for maternal age, race and ethnicity, education, obesity and tobacco smoke exposure.

Researchers found that mothers included in this study tended to be minorities (54% Hispanic; 30% black) who had not completed schooling (66% had less than 12 years of education), yet the majority were nonsmokers (86%).

According to study results, exposure to higher PM_2.5 levels between 13 and 20 weeks gestation increased the odds of developing asthma among male infants. Compounding this association, males born to mothers who reported higher levels of prenatal stress in addition to higher PM_2.5 exposure were particularly affected.

As determined by Bayesian distributed lag interaction models, PM_2.5 exposure was a significant risk factor for asthma development among males born to mothers with high prenatal stress (OR=1.20, 95% CI=1.10-1.34; per IQR increase in PM_2.5) and marginally significant among males born to mothers with low prenatal stress (OR=1.06, 95% CI=0.94-1.20). However, no significant associations were found among girls, regardless of prenatal stress level.

“Just as clinicians counsel all women about the hazards of smoking in pregnancy, the overwhelming evidence linking stress to asthma risk in children should prompt the same universal counseling in the health care provider’s office,” Lee said. “Importantly, the goal need not to be to eliminate all stress, but rather to remove stress when possible and enhance coping mechanisms with the goal of reducing stress to more manageable levels.” —by Katherine Bortz.

Reference:

Lee A, et al. Abstract 8941. Presented at: The 2017 American Thoracic Society International Conference; May 19-24, 2017; Washington, D.C.

Disclosure: The researchers report no relevant financial disclosures.