Non-Asthmatic Adolescents Exposed to Secondhand Smoke At More Risk for Respiratory Illness

Ashley L. Merianos, PhD, CHES

Adolescents without asthma exposed to secondhand smoke are at higher risk for both respiratory illness and increased care provider visits, according to a recent study.

Prior to the study, researchers faced a gap in evidence in how tobacco smoke exposure effects the respiratory symptoms, overall health, and health care visits of adolescents without asthma, study author Ashley L. Merianos, PhD, CHES, assistant professor at the University of Cincinnati, told MD Magazine®.

“The majority of literature focuses on younger children, broad age ranges, or those with asthma diagnoses,” Merianos said.

Secondhand smoke contains over 7000 chemicals, hundreds of which are toxic. Close to 70 are proven to be cancer-causing agents, according to the US Centers for Disease Control and Prevention (CDC).

Exposure to secondhand smoke can cause scores of health issues, including more frequent and severe asthma attacks, respiratory infections, ear infections, and sudden infant death syndrome (SIDS).

For this study, researchers conducted a secondary analysis of the Population Assessment of Tobacco and Health (PATH) Study between. This was a longitudinal cohort where tobacco-use behavior and related health outcomes in US adolescents were measured. Subjects totaled 7389 nonsmoking adolescents without asthma.

Adolescents self-reported 3 exposure variables: living with a smoker, secondhand smoke exposure inside the home, including visitors and workers (cigarettes, cigars, cigarillos, or filtered cigars), and greater than 1 hour of secondhand smoke exposure within the previous 7 days (at home, in a car, at school or outdoors).

Symptoms within the last 12 months were also self-reported: shortness of breath, finding it hard to exercise, chest wheeze during or after exercise, wheezing or chest whistling, wheezing that disturbed sleep, limited speech to 1 or 2 words because of wheezing, and dry cough (not associated with a chest infection or cold) that interferes with sleep.

Health indicators included overall health, physical health, and frequency of missing school because of illness. Parents reported the number and reasons for ER (emergency room) or UC (urgent care) visits within the last 12 months.

Results showed that adolescents with all 3 exposure variables were at higher risk of reporting shortness of breath, difficulty exercising, wheezing during or after exercising, and dry cough at night (P < 0.001).

Those that lived with a smoker (P < 0.001) and had home exposure to secondhand smoke (P = 0.02) had higher risk of reporting wheezing or whistling in the chest, but only adolescents with home exposure (P = 0.02) were at increased risk for wheezing that disturbed sleep.

Participants who reported all three exposure variables were less likely to report very good or excellent overall health and physical health status and 1.5 times more likely to report they sometimes, often or very often missed school because of illness (all P< 0.001).

More ER and/or UC visits were associated with reporting all three exposure indicators (both P < 0.001); those with secondhand smoke exposure had a mean of 1.62 - 1.65 visits compared with unexposed subjects, who had a mean of 1.42 - 1.48 visits.

Merianos said she was surprised to see the relatively high rates of secondhand smoke-related respiratory symptoms, such as shortness of breath and wheezing, among adolescents without asthma.

“Our study highlights the potential impact [secondhand smoke] has on related symptomatology and acute healthcare utilization,” Merianos said. “Implementing clinical intervention efforts that follow the clinical practice guidelines for treating tobacco use and dependence would be beneficial in emergency and urgent care settings. The first step would be to screen all adolescents in these settings in order to identify and prevent tobacco smoke exposure.”

Relying on adolescent report of secondhand smoke exposure might have resulted in underreporting or over-reporting. Merianos added that future research should use biochemically validated secondhand smoke exposure and/or medical record review.

The study, “Adolescent Tobacco Smoke Exposure, Respiratory Symptoms, and Emergency Department Use,” was published online in Pediatrics this week.