Prenatal Nicotine Exposure May Increase Obesity Risk
It's well known that smoking decreases appetite in adults, that smokers typically weigh less than non-smokers and that they tend to gain weight after kicking the habit. But some recent research suggests that there is another, quite different side to the link between smoking and weight gain.
"The epidemiological finding here is that, although offspring of smokers may have lower birth weight, these offspring grow at a more rapid rate, so they have a greater tendency to childhood obesity," says Ed Levin, Ph.D., a professor in the department of psychiatry and behavioral sciences at Duke University Medical Center.
"We had done a series of laboratory studies to look at how to look at how prenatal nicotine exposure impairs cognitive function," says Levin. "There was a recent European study that looked at children of women who smoke, showing the greater tendency to obesity. So we looked back through our old data sets and found that prenatal nicotine exposure increased the weight gain in laboratory rats as well, so that we were able to show a cause-and-effect relationship."
Levin says this increase in childhood obesity may be caused by nicotine's suppression of a neurochemical response that affects metabolism. "Its effects on nervous system development, whenever it's given prenatally, actually blunt the responses that would cause fat to be mobilized," he says. "Our hypothesis is that the offspring, their children, would lay down the fat but be unable to mobilize it. So they would just get more and more obese."
Given America's growing obesity crisis, Levin expects there will be interest among the public health community in the research.
"Premature deaths linked to obesity now exceed 300,000 a year," Levin says. "Obesity is approaching smoking as a leading preventable cause of death, so there's enormous interest in trying to determine the causes.
"Certainly, increased eating and decreased activity play a large role, but there may also be a role played by nicotine and other intoxicants. We're also looking at the effects of pesticide exposure as possibly having a similar effect."
So, in light of these early findings, are we likely to see yet another health warning on cigarette packs someday? "Certainly cigarette smoking has a lot of adverse effects," adds Levin. "This may be one additional one."