Breathing second-hand smoke during childhood can lead to long-term breathing and health problems, and a shorter life expectancy, according to a new scientific statement from the American Heart Association.
Even though the harms of exposing kids to cigarette smoke are well known – asthma and lung infections among them – many children still breathe this smoke at home or in public places or while riding in cars or buses, noted Dr Geetha Raghuveer, lead author of the statement.
“Minority children and those from poor backgrounds are exposed more often,” Raghuveer said.
“Cigarette smoking is very addictive and a stress reliever. This, along with easy access, is likely the reason that it is still prevalent.”
Overall, an estimated 24 million non-smoking children and youths are exposed to second-hand smoke in the US, largely because of parents who smoke.
That translates to four in 10 school-aged children and one in three adolescents, Raghuveer and colleagues note in the statement published in the journal Circulation.
In 2012, researchers found a nicotine by-product called cotinine in blood samples from nearly 41 percent of US children aged three to 11, and in 34 percent of kids ages 12 to 19 – despite declines over recent decades in both adult smoking rates and the proportions of young children and adolescents living with smokers.
Poor and non-white children were disproportionately affected.
Those blood tests found 68 percent of low-income children and 43 percent of minority youth were exposed to second-hand smoke.
While Hispanic children were slightly more likely to be exposed than white kids, the problem was most pronounced among black children.
“It is a socio-economic and a health care associated disparity issue,” said Dr Avni Joshi, a paediatrics researcher at the Mayo Clinic in Rochester, Minnesota, who wasn’t involved in the statement.
“Parents do not understand or are oblivious to the gravity of second- and third-hand smoke exposure and possible effects.
"This may be related to their level of education, access to health care and role modelling in the community.”
Children are more likely to become smokers themselves if their parents smoke.
Besides impacting heart function by causing damage to arteries, exposure to second-hand smoke has been associated with other cardiovascular risk factors, including obesity, high cholesterol and insulin resistance – which is linked to diabetes.
While doctors have warned parents about the dangers of second-hand smoke for years, recent research has helped explain why this can be dangerous for kids, the statement authors note.
Chemicals in second-hand smoke can cause changes to blood flow, blood vessels, blood pressure and heart rhythm.
Children are especially vulnerable to second-hand smoke exposure in part because they cannot control tobacco use in their surroundings and they appear to be particularly susceptible physically to the smoke’s effects.
But the effects of second-hand smoke may be difficult for parents to see while children are young, said Dr Annie Lintzenich Andrews, a paediatrics researcher at the Medical University of South Carolina, who also wasn’t involved in the statement.
“Avoidance of second-hand smoke exposure might not be on the top of many parents’ list of priorities due to so many competing daily stressors like getting kids to school, paying the bills, supplying nutritious meals,” Andrews said.
“Also, there are often not immediate, tangible negative consequences to second-hand smoke exposure in children, making it difficult for parents to appreciate the risks it poses to their children.”