Compared with other overweight children, overweight siblings of children with type 2 diabetes mellitus have a significantly higher prevalence of abnormal glucose tolerance, a risk factor for diabetes, according to researchers at the Children’s Hospital of Philadelphia.

“These siblings,” lead investigator Dr. Sheela N. Magge told Reuters Health, “have a unique combination of genetic and environmental risk factors. We found that the obese sibling group had four-times higher odds of having abnormal glucose tolerance - pre-diabetes and diabetes - compared to the control group.”

Magge and colleagues studied 62 obese children, aged 8 to 17 years, who had at least 1 sibling aged 12 years or older. Twenty children had a sibling with diabetes; 42 acted as controls, according to the study, published in the Journal of Pediatrics.

The prevalence of abnormal glucose tolerance was 40 percent in the group with diabetic siblings and 14.3 percent in the controls. However, there were no differences in insulin resistance or in hemoglobin A1c between groups, two additional indications of diabetes or high risk.

“These obese siblings represent a particularly high risk group to target for type 2 diabetes mellitus screening and prevention studies,” Magge concluded.

SOURCE: Journal of Pediatrics, online December 9, 2008.