By Kerry Grens
1:27 PM EDT, September 21, 2012
NEW YORK (Reuters Health) - Mirroring the results of research in adults, a new study shows that white children are at a higher risk of breaking a bone than children of other races.
The researchers say that genetics might have something to do with the differences, but it's also possible that environmental factors - such as participation in sports - could play a role.
"What looks like a racial disparity may actually reflect a difference in exposure to physical activities with higher risk for fractures, such as competitive, organized sports," said Dr. Leticia Manning Ryan, a professor at Children's National Medical Center in Washington, D.C., who did not participate in the research.
Earlier studies have shown that white women are more likely to suffer a fracture than black women (see Reuters Health report of May 3, 2005).
Tishya Wren, the lead author of the study and professor at Children's Hospital Los Angeles, said her study stemmed from a larger research program looking at children's bone health.
The study included 1,470 girls and boys aged six to 17 years old, whose bone density and broken bones were tracked for six years.
"When I separated our data by race...we noticed this very interesting relationship, which hasn't really been recognized (in children) before," Wren said.
She and her colleagues found that 22 percent of the white kids had had a fracture, while only 12 percent of the other children had experienced a fracture.
White boys appeared to be the most at risk. By the end of the study, about 28 percent had had a fracture, compared to about 18 percent of white girls, 12 percent of non-white boys and six percent of non-white girls.
Most of the fractures occurred while the kids were playing sports, and Wren's group found that lower body fat and more participation in sports were tied to an increased risk of fracture.
For instance, playing sports more than four days per week was tied to a 35 percent increased risk of having a fracture, the group reports in The Journal of Pediatrics.
After the researchers took into account risk factors, such as how many sports the kids played and their body type, they still found that white children had about a two-fold risk of fracturing a bone.
"We think some of it must be related to a genetic type of effect," Wren told Reuters Health. "We also think there might be something inherent in the bone itself that's causing it to be more susceptible to fracture."
SOCIOECONOMICS MAY PLAY A ROLE
Still, Ryan noted, it's possible that the study didn't fully capture how much exposure kids had to high-risk activities, because the researchers didn't examine the children's socioeconomic status.
Ryan said other studies have shown that more children from wealthier families are more likely to play organized sports.
"I would use caution in definitively stating that these findings reflect a racial disparity without incorporating socioeconomic status," she told Reuters Health.
Wren said that until the contributors to the increased risk of broken bones are nailed down, it is important to use the findings to keep parents and doctors aware of the risks.
She said she would not tell parents to avoid sports to reduce kids' risks, because other studies have found that kids with higher body mass and less dense bone - signs indicative of being inactive - are at a greater risk of having a fracture from low-impact injuries.
SOURCE: http://bit.ly/VgWgH8 The Journal of Pediatrics, online September 12, 2012.
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