The newly discovered variants do not appear in obese adults, leading researchers to conclude that they are linked specifically to childhood obesity. Results of the study were published online in the April 8 edition of the journal Nature Genetics.
Previous studies have identified gene variants contributing to obesity in adults and in children with extreme forms of the condition, but relatively little is known about genes implicated in regular childhood obesity."The Center for Applied Genomics at the Children's Hospital of Philadelphia has recruited and genotyped the world's largest collection of DNA from children with common obesity," said Dr. Grant. Researchers conducted a meta-analysis by combining results from similar datasets from around the world to gain sufficient statistical power to detect novel genetic signals.
Investigators analyzed 14 previous studies encompassing 5,530 cases of childhood obesity and 8,300 control subjects, all of European ancestry. Two novel loci were identified, which Dr. Grant said indicates that the intestine may play a role, although exactly what is unknown. According to the Centers for Disease Control and Prevention (CDC) in Washington, DC, childhood obesity can lead to many long term health problems such as type 2 diabetes, high blood pressure, depression, as well as social and behavioral problems.
In the United States, 17% of children and adolescents are considered obese -- that is more than three times the rate of the previous generation. The World Health Organization, estimates that the number of overweight children in 2010 was 42 million -- the majority of whom live in developing countries. This discovery provides researchers with new ways to examine the genetics of common childhood obesity.
Although environmental factors, such as food choices and sedentary habits contribute to the increasing rates of obesity in childhood, studies of twins and other family-based evidence have suggested a genetic component to the disease as well. It’s hoped that this discovery will lead to new, individualized interventions or preventive measures for children carrying these genetic markers.