Prenatal Smoke Exposure Linked to Asthma in Children and Their Poor Response to Asthmatic Treatment
In utero smoke exposure is already known to cause serious developmental deficiencies for the unborn child that can lead to lifelong disability. Smoking during pregnancy increases the risks of several obstetric complications, including sudden infant death syndrome (SIDS), and can lead to poor physical and mental health in the child such as psychiatric disorders, behavioral problems, academic performance, and cognitive development. A new study has not only affirmed that prenatal smoking leads to respiratory problems in the child, such as asthma, but now researchers have found that it can also diminish the child’s response to asthmatic therapy.
Lead researcher Dr. Robyn Cohen, of Philadelphia’s Drexel University College of Medicine, Department of Pediatrics, and her colleagues sought to discover the possible impacts of in utero smoke exposure on respiratory function in asthmatic children since little research has previously explored these children’s response to traditional asthma therapy. Using data from the Childhood Asthma Management Program (CAMP), the researchers evaluated 1,041 children between the ages of 5 to 12 who had histories of mild to moderate asthma and had participated in a 4-year clinical trial of inhaled asthma medications. Researchers assessed the possible impacts of parents' self-reported prenatal smoke exposure on the asthmatic children’s response to inhaled corticosteroid budesonide medication (known under the brand name Pulmicort) used in pediatric asthma therapy.
Airway responsiveness is a key indicator for asthma severity, and inhaled steroids are the standard treatment for persistent asthma. Although both unexposed and exposed children showed improvement with the inhaled corticosteroid asthma treatment, the asthmatic children who had been exposed to smoke in the womb had 26% less improvement in airway responsiveness over time. In fact, the children with prenatal smoke exposure had less improvement after starting treatment, and some even showed no improvement. Furthermore, unexposed children showed considerably greater improvement than untreated children. Overall, prenatal smoke exposure significantly decreased the effectiveness of the inhaled corticosteroid budesonide in asthmatic children.
The study’s findings may help explain why children with prenatal smoke exposure respond poorly to asthmatic therapy. Prenatal smoke exposure was found to affect the development of the child’s lung structure or smooth muscles that control their airways—both of which influence the child’s response to asthma treatment. The researchers suggest that these children may require a second medication for asthmatic therapy in addiction to inhaled steroids, such as oral medications like leukotriene modifiers.
The asthma study adds further evidence of the negative impact of in utero smoke exposure. In July, a similar study released by the American Psychiatric Association had found that adolescents with asthma are twice as likely to make suicide attempts as those without asthma. Following their latest study, the researchers explain that more investigation would be needed to determine the physiological and respiratory mechanisms that are affected by prenatal smoke.
The researchers insist that smoking cessation counseling with pregnant women is highly important in an effort to thwart the multiple consequences to their unborn children. The study was published this month in the Journal of Allergy and Clinical Immunology and is available online at www.jacionline.org.
Sources: American Psychiatric Association, Large Studies Link Asthma and Air Pollution to Suicide Risk, July 15, 2010
Reuters. Amy Norton, Prenatal smoke tied to poorer asthma-drug response, August 10, 2010
