New research suggests that young kids growing up around tobacco smoke are three times more likely to develop attention deficit hyperactive disorder ( ADHD) than those who aren't, and the link is stronger in those who have more than a couple of hours exposure each day.
"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 team concludes in the journal Tobacco Control.
The international team, led by Alicia Padron from the University of Miami Miller School of Medicine in the US, analysed data that was gathered by the Spanish National Health Interview Survey between 2011 and 2012, which includes pertinent lifestyle information from 2,357 parents with kids between four and 12 years old.
The survey questioned the parents on the secondhand smoke exposure levels of their children, and found that 8 percent of the kids had been diagnosed with a probable mental disorder. According to Shereen Lehman at Reuters, the data also showed that, "about 7 percent of the kids were exposed to secondhand smoke for less than one hour per day, and 4.5 percent were exposed for an hour or more each day."
"After taking the parent's mental health, family structure and socioeconomic status into consideration, children who were exposed to secondhand smoke for less than one hour per day were 50% more likely to have some mental disorder compared to kids not exposed at all.
And children who were habitually exposed to secondhand smoke for an hour or more each day were close to three times more likely to have a mental disorder.
In addition, kids exposed less than one hour per day were twice as likely to have ADHD as kids who weren't exposed, and children exposed for an hour or more on a daily basis were over three times more likely to have ADHD."
But limitations of the study are pretty significant - while the researchers have found a clear link between exposure to secondhand smoke and ADHD, they can't prove causation, and there is not sufficient research to explain why smoke would have this affect on a young, developing mind. That said, even in its early stages, research like this is super-important, and hopefully in the future some more concrete conclusions can be drawn.
And besides, as Lucy Popova from the Centre for Tobacco Control Research and Education at the University of California, San Francisco in the US, who was not involved in the research, told Reuters, there's enough evidence already to suggest that exposing your child to secondhand smoke is a bad idea anyway, regardless of a possible ADHD link.
"Research on effects of secondhand smoke on mental health have been really just emerging and this study really contributes to this growing body of evidence that exposure to secondhand smoke in children might be responsible for cognitive and behavioural problems," she said.
Source: Scientific American