Asthmatic children exposed to second-hand smoke are more likely to be hospitalized

Children with asthma who are exposed to second-hand smoke (SHS) at home are nearly twice as likely to be hospitalized vs children with asthma who are not exposed, according to a study published online September 24, 2015 in the Annals of Allergy, Asthma and Immunology, the scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI).

Exposure to SHS can trigger asthma exacerbations in children. Previous studies have linked increased asthma symptoms, health care use, and deaths in children exposed to SHS, but the risk has not been quantified uniformly across studies.

“Previous studies have linked SHS exposure with increased asthma prevalence, poorer asthma control, and increased symptoms,” said Zhen Wang, PhD, lead author of the study from the Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery at Mayo Clinic in Rochester, Minnesota. “We wanted to quantify the strength of the association, and to show just how much greater the risk is of hospitalization for kids with asthma who are exposed to SHS in the home.”

Dr. Wang and colleagues examined 25 studies investigating cigarette smoking exposure at home. More than 430,000 children were included, with a mean age of 7.6 years of age. The majority (96%) of the studies investigated smoking exposure at home.

Inclusion criteria for the meta-analysis included studies that evaluated children with SHS exposure and reported outcomes of interest with asthma severity including exacerbations. Random effect models were used to combine the outcomes of interest (hospitalization, emergency department or urgent care visits, severe asthma symptoms, wheeze symptoms, and pulmonary function test results) from the studies that were included.

A total of 1,945 studies were identified in the search and 25 studies met the inclusion criteria. Children with asthma and SHS exposure were found to be twice as likely to be hospitalized for asthma than children with asthma but without SHS exposure. SHS exposure also was significantly associated with emergency department or urgent care visits, wheeze symptoms, and lower ratio of forced expiratory volume in 1 second to forced vital capacity.

“The results of this review serve as a reminder to parents of just how dangerous it is to expose their children to SHS,” said allergist Avni Joshi, MD, ACAAI member and senior author of the article. “Allergists are trained to work with both children and adults to get their asthma under control. Controlled asthma means fewer emergency room visits, hospitalizations, and proper use of long-term controller medications. An allergist can also help avoid over-reliance on quick-relief medications and work on modifiable risk factors for poor asthma outcomes like assessing and addressing tobacco exposures. Some allergists have developed family-centered tobacco control programs that address parents’ tobacco use during a clinic visit for a child with asthma.”