Children who are overweight or obese face an increased risk for gallstones, according to a Kaiser Permanente study published in the Journal of Pediatric Gastroenterology & Nutrition.

Researchers found that children and adolescents who were overweight were twice as likely to have gallstone disease, compared to children and adolescents who had a normal body mass index. Those who were moderately obese were four times as likely to have gallstones and those who were extremely obese were six times as likely to have gallstones.

The study was based on information in the electronic health records of more than 510,000 children ages 10 to 19, from 2007 through 2009, who were members of Kaiser Permanente Southern California.

The size and diversity of this population-based study allowed researchers to explore racial and ethnic disparities. Hispanic youth were more likely to have gallstones than youth of other races and ethnicities.

"Although gallstones are relatively common in obese adults, gallstones in children and adolescents have been historically rare," said study lead author Corinna Koebnick, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation. "These findings add to an alarming trend -- youth who are obese or extremely obese are more likely to have diseases we normally think of as adult conditions."

Researchers found a stronger association between obesity and gallstones in girls than in boys. Girls who were obese and extremely obese were six and eight times more likely, respectively, to have gallstones than girls who were underweight or of normal weight, while obese and severely obese boys were more than twice and three times as likely to have gallstones as their normal or underweight counterparts.

Gallstone disease is a major health problem in the United States, affecting an estimated 20 million adults. Symptoms of gallstones include recurrent abdominal pain and nausea, although many people with gallstones have no symptoms. Gallstones can block the passage of bile into the intestine, which in turn can cause severe damage or infection in the gallbladder, liver, or pancreas and, if left untreated, the condition can be fatal.

"The high rate of gallstones in obese children and adolescents may surprise pediatricians because gallstone disease is generally regarded as an adult disorder. Since obesity is so common, pediatricians must learn to recognize the characteristic symptoms of gallstones," said George Longstreth, MD, senior study author and a gastroenterologist from Kaiser Permanente San Diego Medical Center.

"With increasing numbers of cases of gallstones in children, we wanted to better understand the potential role of risk factors such as obesity, gender, ethnicity, and oral contraceptive use," added Koebnick. "With childhood obesity on the rise, pediatricians can expect to diagnose and treat an increasing number of children affected by gallstone disease. It is important to identify other factors that increase risk as well."

This study is part of ongoing research and community programs that aim to identify and treat childhood obesity. The Kaiser Permanente Southern California Children's Health Study found that 7.3 percent of boys and 5.5 percent of girls under the age of 20 years are extremely obese.