A new study has found that when children are exposed to second-hand cigarette smoke in the home, they are three times more likely to have attention deficit hyperactive disorder (ADHD) than kids who are not exposed.
The association became even greater for children who were exposed to smoke one or more hours every day, according to researchers. When taking into account parents' mental health and other factors, the results remained the same, says Shereen Lehman for Reuters.
"We showed a significant and substantial dose–response association between (secondhand smoke) exposure in the home and a higher frequency of global mental problems," the authors write in Tobacco Control.
The CDC reports that two of every five children in the US are exposed to secondhand smoke regularly. Alicia Padron of the University of Miami Miller School of Medicine in Florida and colleagues in Spain looked at 2011-2012 data from the Spanish National Health Interview Survey. Parents of 2,357 children aged four to 12 reported the amount of time their children were exposed to secondhand smoke each day.
Then they completed a questionnaire to evaluate their children's mental health. Of the over 2,000 children in the study, 8% had a probable mental disorder. Also the survey showed that 7% of kids were exposed to smoke less than one hour a day, and 4.5% were exposed to an hour or more each day. Children who were exposed smoke for less than one hour a day were 50% more likely to have some mental disorder compared to kids who had no secondhand smoke exposure at all.
Children who were exposed to smoke for an hour or more each day were almost three times more likely to have a mental disorder. Also, kids exposed less than one hour per day were twice as likely to have ADHD as kids who were not, and children who were exposed for an hour or more daily were over three times more likely to have ADHD.
"The association between secondhand smoke and global mental problems was mostly due to the impact of secondhand smoke on the attention-deficit and hyperactivity disorder," the authors write.
Researchers caution that the study looks at a single point in time, so it cannot prove that secondhand smoke exposure causes mental health problems. Frank Bandiera, a researcher with the University of Texas Health Science Center in Houston who was not involved in the study, thought it was smart that the researchers "controlled for parents' mental health in the new study because that could be a confounder."
Still, Bandiera noted that the mental disorders had not actually been diagnosed by a doctor. Even so, many physical diseases have been linked to secondhand smoke and he advises parents not to smoke at home.
Dr. Adam Goldstein, who is director of the tobacco intervention programs in the UNC School of Medicine, writes in an opinion piece published in the March/April 2015 issue of Annals of Family Medicine, that exposing children to secondhand smoke is a form of child abuse.
"Purposeful and recurrent exposure of children to secondhand smoke by a parent is as abusive as many other commonly accepted physical and emotional traumas of children, like drunk driving or leaving children in a hot car unattended," says Dr. Goldstein, who is director of the UNC School of Medicine's Tobacco Prevention and Evaluation Program (TPEP) and its Nicotine Dependence Program (NDP).
Goldstein adds that intervention can include counseling parents who smoke, legislation and even court relief.