Overweight teenagers are often blamed for their condition but a new study finds their mothers may have to bear much of the burden if they smoked during pregnancy.
Researchers say prenatal exposure to maternal cigarette smoking appears to be linked with an increased risk for adolescent obesity, and is possibly related to subtle structural variations in the brain that create a preference for eating fatty foods, according to a report published Online First byÂ Archives of General Psychiatry,Â a JAMA Network publication.
"Prenatal exposure to maternal cigarette smoking is a well-established risk factor for obesity, but the underlying mechanisms are not known," the authors write as background information. "Preference for fatty foods, regulated in part by the brain reward system, may contribute to the development of obesity."
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 BMI, and a significantly higher total body fat compared with nonexposed participants.
"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 authors conclude.
Amirreza Haghighi, M.D., of 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.
The authors defined exposed as having a mother who smoked more than one cigarette a day during the second trimester of pregnancy, and not exposed as having a mother who did not smoke one year before (and throughout) the pregnancy.