Smoking during pregnancy can lead to obese teens

Researchers from Canada found that exposing kids to cigarette smoking at prenatal stage could cause subtle structural variations in the brain that create a preference for eating fatty foods.

"Prenatal exposure to maternal cigarette smoking may promote obesity by enhancing dietary preference for fat, and this effect may be mediated in part through subtle structural variations in the amygdala," the researchers said in a statement.

Amygdala is the part of the brain that plays a role in processing emotions and storing memories.

Amirreza Haghighi from the Hospital for Sick Children, Toronto, Canada, and colleagues, studied 378 adolescents age 13 to 19 years who were recruited through high schools in one region of Quebec, Canada, as part of the ongoing Saguenay Youth Study.

Participants were grouped as exposed to maternal smoking or nonexposed to maternal smoking.

The authors defined exposed as having a mother who smoked more than one cigarette a day during the second trimester of pregnancy, and nonexposed as having a mother who did not smoke one year before (and throughout) the pregnancy.

Exposed versus nonexposed participants weighed less at birth and were breastfed for shorter periods of time.

At the time of analysis, exposed participants had a marginally higher body weight and Body Mass Index, and a significantly higher total body fat compared with nonexposed participants.

Exposed versus nonexposed participants also exhibited a significantly lower volume of the amygdala and the authors found that, consistent with its possible role in limiting fat intake, amygdala volume correlated inversely with fat intake.

The study was published in the journal Archives of General Psychiatry.