Childhood Obesity Might Be Linked to Strain of Cold Virus
MONDAY Sept. 20, 2010 -- At least part of the blame for childhood obesity might be traced to a unexpected cause -- a certain strain of the virus that causes the common cold.
New research shows that youngsters who were infected by adenovirus 36, which causes the common cold and slight gastrointestinal upset, were an average of 50 pounds heavier than children who hadn't been infected by this particular strain.
"Obesity and body weight regulation is far more complex than is typically discussed, and these data support the idea that a viral infection could be one important cause of obesity," said study senior author Dr. Jeffrey B. Schwimmer, director of the weight and wellness program at Rady Children's Hospital in San Diego.
This study doesn't, however, suggest that people should give up on healthy eating and exercise. "Regardless of the extent to which this impacts body weight, there's no question that eating healthfully and having regular, fun physical activity is good for you. The reason we care about these behaviors is improving health," said Schwimmer.
What Schwimmer does hope the findings will do is get people to "move away from assigning blame, and broaden the way we think about obesity. Currently, there's a somewhat simplistic belief that obesity is just a person's own fault, or in the case of children, the fault of the family. But, that's an overly simplistic view, and it's not helpful," he said.
Other studies, done in animals and human adults, have already shown an association between viral infections and obesity, but the exact relationship between those factors still isn't well known, according to Schwimmer.
The current study included 124 children between the ages of 8 and 18. Sixty-two percent of the children were Hispanic, 27 percent were white and 11 percent were black. Fifty-six percent were male. More than half of the children -- 67 -- were considered obese based on their body-mass measurements for their age and gender.
Fifteen percent of the children had antibodies to adenovirus 36 (AD36), which means that at some point, they had been infected with this virus. Schwimmer said this particular strain of adenovirus was first identified in the 1980s.
Almost one in four (22 percent) obese children tested positive for AD36 compared to just 7 percent of the non-obese children. On average, children who were positive for a previous adenovirus 36 infection were about 50 pounds heavier than those who tested negative.
Even within the entire group of obese children, those who were AD36-positive weighed about 35 pounds more than obese children who hadn't been infected with AD36.
Results of the study appear in the Sept. 20 online issue of Pediatrics.
If the association proves true, Schwimmer said that a vaccine could be developed against AD36 that might help prevent obesity -- although that's still a long way off. In addition, he said, for those who've already been infected with AD36, knowing that there's a potential viral cause might eventually lead to changes in the way certain people are treated for obesity. "That knowledge might lead to more aggressive measures earlier on if we see someone isn't losing weight as well," said Schwimmer, who added that his study was the first of its kind. He believes the findings raise more questions than they answer when it comes to optimal treatments for obesity.
For his part, Dr. Goutham Rao, clinical director of the Weight Management and Wellness Center at Children's Hospital of Pittsburgh, said the findings bring up the "age-old chicken or egg problem -- Does this virus disrupt certain pathways and cause obesity? Or, do obese kids tend to have this virus more often?"
In addition, he noted that the number of children with the infection was relatively small -- just 19 kids.
"People want a magic solution," Rao said, "but unfortunately we don't have one. What people can do is focus on a child's behaviors and eliminate the unhealthy behaviors."
He said that kids shouldn't skip breakfast and should limit sweet beverages (soda and juice) and fast food. Physical activity needs to be a daily habit and families need to eat meals together as much as possible, he advised. In addition, parents need to limit time watching TV, computer time and time spent playing video games.
"If you can change these behaviors, you'd reduce most childhood obesity," Rao believes.
For more on the known causes of obesity, read this information from the U.S. National Heart, Lung, and Blood Institute.
Posted: September 2010