ADOLESCENT MEDICINE: Impact of tobacco smoke exposure

“Almost 1 in 4 children between 3 and 11 years of age in the United States lives in a household with a smoker, so ongoing efforts are needed to prevent exposure in utero, infancy, and childhood to the detrimental effects of secondhand smoke (SHS) and thirdhand tobacco smoke,” stated Sharon McGrath-Morrow, MD.

In the presentation “Impact of In Utero Secondhand Smoke and Thirdhand Tobacco Smoke Exposure on Children,” McGrath-Morrow cited data that, among the states, Kentucky, West Virginia, and Oklahoma are reported to have the highest prevalence rates of smoking at 25%, with Utah, California, and Washington having the lowest prevalence between 9.8% and 14.9%. There are approximately 1 billion smokers worldwide, with smoking estimated to cause 5.4 million deaths a year.

Initiation of smoking frequently begins in childhood, said McGrath-Morrow. One half of adult smokers in the United States are regular smokers by 18 years of age with 5.2% of middle school children and 17.2 % of high school students reporting current cigarette use.

It also has been reported that 13% to 15% of pregnant women aged between 15 and 24 years are smokers. Women who smoke during pregnancy are at higher risk for delivering infants who are small for gestational age. Maternal smoking during pregnancy can adversely affect lung development and has been shown to increase the likelihood of wheezing and asthma during the preschool years. Also, offspring of smokers have an increased risk of obesity.

According to McGrath-Morrow, the adverse health effects of SHS have been well described in infants and children. It is estimated that there are approximately 430 excess deaths from sudden infant death syndrome, more than 200,000 episodes of childhood asthma, 150,000 to 300,000 cases of lower respiratory tract illnesses, and more than 700,000 middle ear infections. In addition, severe asthmatics exposed to SHS may be less responsive to inhaled corticosteroids.

There is also emerging evidence that children exposed to thirdhand smoke are at increased risk for adverse health effects, she said.

REFERENCES

World Health Organization (WHO). Tobacco fact sheet. www.who.int/mediacentre/factsheets/fs339/en/. Updated July 2013. Accessed October 18, 2013..

American Lung Association. Trends in tobacco use. www.lung.org/finding-cures/our-research/trend-reports/Tobacco-Trend-Report.pdf. Published July 2011. Accessed October 18, 2013.

Cnattingius S. The epidemiology of smoking during pregnancy: smoking prevalence, maternal characteristics, and pregnancy outcomes. Nicotine Tob Res. 2004;(6 Suppl 2):S125-S140.

Durmus B, Kruithof CJ, Gillman MH, et al. Parental smoking during pregnancy, early growth, and risk of obesity in preschool children: the Generation R Study. Am J Clin Nutr. 2011;94(1):164-171.

Neuman A, Hohmann C, Orsini N, et al; ENRIECO Consortium. Maternal smoking in pregnancy and asthma in preschool children: a pooled analysis of eight birth cohorts. Am J Respir Crit Care Med. 2012;186(10):1037-1043.

Duijts L, Jaddoe VW, van der Valk RJ, et al. Fetal exposure to maternal and paternal smoking and the risks of wheezing in preschool children: the Generation R Study. Chest. 2012;141(4):876-885.

US Department of Health and Human Services. Children and Secondhand Smoke Exposure. Excerpts from The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2007. Available at: www.surgeongeneral.gov/library/reports/smokeexposure/fullreport.pdf. Accessed October 18, 2013.

Stoloff SW, Kelly HW. Updates on the use of inhaled corticosteroids in asthma. Curr Opin Allergy Clin Immunol. 2011;11(4):337-344.

Matt GE, Quintana PJ, Destaillats H, et al. Thirdhand tobacco smoke: emerging evidence and arguments for a multidisciplinary research agenda. Environ Health Perspect. 2011;119(9):1218-1226.

Sharon McGrath-Morrow, MD, MBA, a pediatric pulmonologist, is associate professor, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore Maryland, with a joint appointment in the Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health. She is also director of the Pediatric Pulmonary Fellowship Program.

While the smoking rate among adults has fallen, more than half of children are still exposed to secondhand smoke. Secondhand smoke increases the severity of respiratory illnesses, such as bronchiolitis and influenza, and can cause asthma and worsen exacerbations. Secondhand smoke also increases the risk of ear infections. Even very low levels of exposure are associated with worse scores on cognitive testing and decreased blood antioxidant levels. Smoke exposure in utero has similar effects, and we are learning more about the negative effects of thirdhand smoke as well.

Parents want and expect to be asked about their smoking behaviors, and pediatricians can make a difference by asking parents about their child’s exposure to SHS, advising them to quit smoking or eliminate their child’s exposure, and referring the parent to the local Quitline (1-800-QUIT-NOW). Parents often have a stronger relationship with their child’s pediatrician than with their own providers, allowing pediatricians to play an important role in helping parents quit smoking for the health of their children, and for themselves.

Karen M. Wilson, MD, MPH, is associate professor of pediatrics, University of Colorado Anschutz Medical Campus, Aurora, and section head, Pediatric Hospital Medicine, Children’s Hospital Colorado, Aurora.