By Robert Preidt, HealthDay Reporter

(HealthDay)

FRIDAY, June 10, 2016 (HealthDay News) -- A new study links unemployment during the recent Great Recession with weight gain in children.

"This study tells a dramatic story about the negative and lasting health effects of an economic shock like the Great Recession, effects that have not been fully understood," said study leader Vanessa Oddo. She is a doctoral candidate in human nutrition at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

"Childhood obesity is one of the biggest public health concerns of our time. And since it's not easy to lose weight once it is gained, this period of economic hardship could have consequences that last long into adulthood," Oddo said in a Hopkins news release.

Oddo and her colleagues analyzed data on 1.7 million public school children, aged 7 to 18, in California. They also examined unemployment statistics from counties across the state.

For every 1 percent increase in county-level unemployment between 2008 and 2012, there was a 4 percent higher risk that school children would become overweight.

The average rise in unemployment during that time was 5.4 percent, meaning children's risk of becoming overweight rose roughly 21 percent, according to the researchers.

In 2008, when the recession began, 28 percent of the state's public school children were considered overweight. By 2009, the percentage of overweight kids peaked at 40 percent and was still at 37 percent in 2012, the study found.

Previous studies have shown that even small changes in weight -- 5 percent to 10 percent in children and teens -- can increase their risk of developing chronic diseases later in life, the researchers noted.

However, the new study didn't prove a cause-and-effect relationship between economic hard times and childhood weight gain.

Still, one possible reason for the apparent link may be changes in families' food-buying habits.

"We think they likely gained weight because with decreased economic resources, families may be trading more expensive healthy food like fresh fruits and vegetables for cheaper, higher calorie alternatives such as highly processed convenience food," said study senior author Jessica Jones-Smith. She is an assistant professor in the department of international health at the Bloomberg School of Public Health.

Also, "the stuff that is convenient and tasty is also high in calories and may be the kind of food people turn to in these economically constrained times," she added.

The researchers further noted that during economic downturns, school districts may cut back on sports programs and after-school activities that promote physical activity.

The study was published online June 1 in the Journal of Epidemiology and Community Health.

More information

The U.S. Centers for Disease Control and Prevention has more on childhood overweight and obesity.