Childhood Exposure to Secondhand Smoke Increases Death From COPD in Adulthood

Long-term exposure to secondhand smoke (SHS) during childhood increases the risk of chronic obstructive pulmonary disease (COPD) death in adulthood, according to a new study, which also suggests secondhand smoke exposure in adulthood increases the risk of death not only from COPD but also from ischemic heart disease and stroke.

This is the first study to identify an association between childhood SHS and later COPD death in adulthood, according to the researchers. The study was published in the American Journal of Preventive Medicine.

Secondhand smoke is harmful to the respiratory and vascular systems in both children and adults. The harmful effects of exposure to secondhand smoke from cigarettes has been documented by CDC for decades, and was suspected shortly after the seminal 1964 report, “Smoking and Health.”

Subsequent reports outlined how secondhand smoke causes sudden infant death syndrome, respiratory infections, ear infections, and asthma attacks in infants and children. Adults face risks of coronary heart disease, stroke, and lung cancer, which has prompted efforts to ban smoking in restaurants and casinos to protect workers. According to CDC, no risk-free level of secondhand smoke exposure exists.

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But it is unknown whether childhood exposure to secondhand smoke is associated with mortality in adulthood. Researchers examined associations of childhood and adult secondhand smoke exposure with death from all causes, stroke, and chronic obstructive pulmonary disease among 70,900 never-smoking men and women from the Cancer Prevention Study II Nutrition Cohort, which is funded and maintained by the American Cancer Society.

Study participants, primarily ages 50 to 74 at the beginning of the study, answered questions about their secondhand smoke exposure during childhood and as adults and were followed for 22 years.

Those who lived with a daily smoker throughout their childhood had 31% higher mortality from COPD compared to those who did not.

In addition, secondhand smoke exposure (10 or more hours/week) as an adult was associated with a 9% higher risk of all-cause mortality, a 27% higher risk of death from ischemic heart disease, a 23% higher risk of death from stroke, and a 42% higher risk of death from COPD.

Although the study counted only deaths, the increase in fatal COPD implies that living with a smoker during childhood could also increase risk of non-fatal COPD, according to W. Ryan Diver, MSPH, a lead author of the study. "Overall, our findings provide further evidence for reducing secondhand smoke exposure throughout life,” he said in a statement.

Diver said the increase in COPD mortality corresponds to about 7 additional deaths per year per 100,000 never-smoking study participants.

Reference

Diver R, Jacobs EJ, Gapstur SM. Secondhand smoke exposure in childhood and adulthood in relation to adult mortality among never smokers. Am J Prev Med. 2018;55(3):345-352 doi:10.1016/j.amepre.2018.05.005.