Children who are exposed to secondhand tobacco smoke at home while growing up have a higher chance of developing markers of decreased heart function as adults, according to preliminary research to be presented at the American Heart Association’s Scientific Session 2020.

The researchers examined the health records of more than 1100 adults, who had an average age of 45 years, were 52% female, and who are participants in the ongoing Childhood Determinants of Adult Health study.

The Australia-wide research project initiated in 1985 is investigating the importance of childhood factors in the later development of risk factors for heart disease and stroke. Further, approximately 54% of the participants were exposed to secondhand smoking at home during childhood, with most of the participants evaluated between 2014 and 2019, 34 years after they entered the study as schoolchildren.

The severity of childhood smoking exposure was calculated in 3 ways: the number of smokers in the home, the number of years each child was exposed to tobacco smoking by household members, and the severity of exposure index—which measures the frequency in which a child was exposed to smoke in the home.

In the evaluation, ultrasound imaging was used to measure the global longitudinal strain (GLS) of the left ventricle, the heart’s major pumping chamber. GLS indicates how much the muscles of the left ventricle shorten as they help squeeze blood out of the heart, compared with the resting length of the muscles between heartbeats.

“The GLS can show early changes in the ability of the heart to contract properly and that can provide information on the risk of heart disease,” said Chigoze Ezegbe, MBBS, MPH, in a press release. “Previous research shows that each 1% decrease in GLS has been associated with a 12% higher risk of cardiovascular morbidity and mortality in a low-risk, general population.”

Researchers found that adult global longitudinal strain declined significantly with each additional member of the child’s household who smoked, ranging from 0 to 5 smokers, with more years of childhood exposure to tobacco smoke, and with higher scores on the childhood severity of exposure index.

According to the study authors, the research team is currently examining the cardiovascular effects of secondhand smoke exposure, including alterations in blood pressure and plaque buildup in arteries.

“Recognizing that adult cardiovascular health is influenced by factors across the lifespan including childhood may be important in advocacy initiatives and in implementing interventions to reduce the risks,” Ezegbe said in a press release. “These could include messages and programs that can help prompt parents to protect their children from tobacco smoke and the associated long-term health risks.”

The study has limitations, including not having information on participants’ prenatal exposure to smoking or on the number of cigarettes around them. This information would have been valuable to determine whether there was any dose-response effect to secondhand smoke, according to the study authors.

“Children, especially young children, are typically exposed to tobacco smoke involuntarily, with little choice, yet it clearly can affect their health,” said Rose Marie Robertson, MD, FAHA, deputy chief science and medical officer of the American Heart Association and co-director of the Association’s Tobacco Center of Regulatory Science, in a press release. “This study confirms that children should be protected from passive smoking—because it negatively impacts their health during childhood, and it leads to long-term health consequences in adulthood.”

REFERENCE
Children exposed to tobacco smoke at home have worse heart function as adults. American Heart Association. https://newsroom.heart.org/news/children-exposed-to-tobacco-smoke-at-home-have-worse-heart-function-as-adults. Published November 9, 2020. Accessed November 17, 2020.