Dr. Ketan Shankardass, a social epidemiologist with St. Michael's Hospital in Toronto and Wilfrid Laurier University, said 2 percent might sound low, but it's significant because it is happening in children, whose bodies and eating and exercise habits are still developing. Plus, if that weight gain continues and is compounded over a lifetime, it could lead to serious obesity and health issues said Shankardass, the lead author for the study.
Shankardass studied data collected during the Children's Health Study, one of the largest and most comprehensive investigations into the long-term effects of air pollution on the respiratory health of children.
The children's BMI was calculated each year. Their parents were given a questionnaire to measure their perceived psychological stress that asked how often in the last month they were able or unable to control important things in their life and whether things were going their way or their difficulties were piling up so high they could not overcome them.
Shankardass said it was not clear why the link between stress and obesity existed.
He said parents could change their behavior when they are stressed, to reduce the amount of physical activity in the household or increase the amount of unhealthy food available. Parental stress could also create stress for the children, who cope by eating more or exercising less, or whose stress leads to biological changes that cause weight gain, he said.
The findings were published in the journal Pediatric Obesity.