This is not the first time a study has shown a possible connection between smoking in the mother and ADHD of her child, but previous studies were based on the fact that the mother was self-reported on smoking: a measure that generally underestimates the rate Real smoking, and even more so in pregnant women.
This time, the researchers at the University of Turku measured the level of cotinin in the blood of women who were in their second or third trimester. Cotinine is a biomarker that shows the mother's exposure to nicotine, whether it's her own tobacco, second-hand smoke or even seals.
The higher the level of cotinin in the mother's blood, the greater the risk that your child would have ADHD later, according to scientists.
"This is a fact known in literature for some time, that exposure to cigarettes increases the risk that the child presents ADHD," said Dr. Nancie Rouleau, neuropsychologist at Laval University. who is enjoying a sabbatical year working at Harvard University. The child is most likely to end up with ADHD if the mother consumes a lot of nicotine, which is less the case with light beverages. But we are talking about an association and not a causal connection. "
In fact, one can simply, for now, observe a connection between smoking and ADHD, without being able to say that the first is the direct cause of the second. There is an association, nothing more.
Dr. Rouleau raises several hypotheses about this. As a first step, he says, we know that a mother who smokes a cigar is more likely to give birth to a lowweight or premature baby, which is "one of the biggest risks (of ADHD) currently."
In addition, we know that people who suffer from ADHD and who are not treated are more likely to be consumers of alcohol, drugs or tobacco.
"So I ask myself: do any of the mothers who smoke cigarettes have mothers without ADHD treatment? Asked Dr. Rouleau. So here we have a second causal link, genetics. Yes, mom smokes but is mostly carrier of genes that cause ADHD and that was not controlled here. "
That being said, pregnant women still have an interest in being as far away as possible from nicotine products, either through ADHD or for any other reason.
"It seems to me a very logical recommendation to read scientific literature now. It is a harmful factor to be exposed to tobacco, even for a baby born," said Dr. Nancie Rouleau.
The results of this study are published by the medical journal Pediatrics.