Secondhand Smoke Exposure Linked to Sleep Problems in Children With Asthma CME

From MedscapeCME Clinical Briefs
News Author: Laurie Barclay, MD
CME Author: Charles P. Vega, MD

January 26, 2010 — Exposure to secondhand smoke (SHS) is associated with increased sleep problems among children with asthma, according to the results of a study reported online January 18 and to be published in the February print issue of Pediatrics.

"Adult and adolescent smokers report difficulties with sleep," write Kimberly Yolton, PhD, from Cincinnati Children's Hospital Medical Center in Cincinnati, Ohio, and colleagues. "Young children who are exposed to tobacco smoke have poorer sleep quality. Children with asthma report more sleep problems and are more sensitive to the respiratory effects of tobacco smoke."

The goal of this study was to analyze the association between exposure to SHS and child sleep patterns among a group of 219 children with asthma who were enrolled in an asthma intervention trial and who had regular exposure to tobacco smoke at home. SHS exposure was measured with serum cotinine levels, and the Children's Sleep Habits Questionnaire was used to evaluate sleep patterns based on parental reports.

Statistical analyses allowed adjustment for covariates of age, sex, race, maternal marital status, education, income, prenatal tobacco exposure, maternal depression, Home Observation for Measurement of the Environment total score, household density, asthma severity, and use of asthma medications.

SHS exposure was associated with longer sleep-onset delay (P = .004), sleep-disordered breathing (P = .02), parasomnias (P = .002), daytime sleepiness (P = .022), and overall sleep disturbance (P = .0002).

"We conclude that exposure to SHS is associated with increased sleep problems among children with asthma," the study authors write. "As SHS exposure increased, parents reported that their children had longer delays in sleep onset, more-frequent parasomnias and sleep-disordered breathing, increased daytime sleepiness, and greater overall sleep disturbance."

Limitations of this study include lack of generalizability to children without asthma; wide variance of the degree of SHS exposure; sleep data based only on parental reports; and lack of information on prematurity, which could be an important contributor to sleep problems.

"We report significant associations between SHS exposure, as measured with a biological marker (serum cotinine levels), and sleep problems in children with asthma," the study authors conclude. "Reduction in SHS exposure is an area with the potential for significant impact in the pediatric population."

The National Institutes of Health supported this study. The study authors have disclosed no relevant financial relationships.

Pediatrics. Published online January 18, 2010. Abstract

Clinical Context

Sleep problems are very common during childhood, with a prevalence exceeding 25%. Children with asthma experience an even higher prevalence of sleep problems during childhood, with up to 60% of these children reporting sleep problems. Fortunately, appropriate treatment of asthma can improve sleep efficiency.

Sleep problems in childhood are more than just an annoyance. Inadequate sleep in this population is associated with poor school performance, somatic complaints, and behavioral problems. Children with sleep problems are also at higher risk for obesity.

Smoking has been associated with sleep problems, and there is some suggestion that SHS can negatively affect sleep in children. The current study tests this hypothesis among children with asthma.


Study Highlights

•Study participants were between the ages of 6 and 12 years and had received treatment of physician-diagnosed asthma in the past year. All participants were exposed to at least 5 cigarettes' worth of SHS per day at home.
•Children with other respiratory tract diseases and heart disease were excluded from study participation.
•Researchers collected detailed information regarding the volume and location of SHS exposure. Children provided baseline serum cotinine levels to corroborate SHS exposure.
•Sleep patterns were measured with the Children's Sleep Habits Questionnaire, which measures sleep quality within the previous 2 weeks.
•The main outcome of the study was the interaction between SHS and sleep quality. This result was adjusted to account for asthma severity, demographic data, and social factors.
•219 children with a mean age of 9.4 years provided data for study analysis. 61% of participants were boys, and 56% were black.
•The median amount of daily cigarette exposure at home was 13 cigarettes.
•The mean sleep time was 9.6 hours per night, and 93% of children had a sleep disturbance score that was considered clinically relevant.
•On multivariate analysis, higher levels of SHS exposure were associated with increased rates of sleep-onset delay, parasomnias, daytime sleepiness, sleep-disordered breathing, and total sleep disturbance scales.
•SHS had no significant overall effect on sleep duration, sleep anxiety, or night wakings.
•Boys were particularly sensitive to the effects of SHS in increasing sleep anxiety, whereas SHS promoted higher levels of sleep-onset delay among girls.

Clinical Implications

•More than one quarter of all children have sleep problems, and the prevalence of sleep problems can increase to 60% among children with asthma. The treatment of asthma can reduce sleep problems. Inadequate sleep in children is associated with poor school performance, somatic complaints, obesity, and behavioral problems.
•The current study demonstrates that SHS can promote increased rates of sleep-onset delay, parasomnias, daytime sleepiness, sleep-disordered breathing, and total sleep disturbance among children with asthma. SHS had no significant overall effect on sleep duration, sleep anxiety, or night wakings.