New research on a group of Dutch children with Down syndrome is calling attention to the staggering number of kids with the disorder who are overweight.

In a study of nearly 1,600 children with Down syndrome in the Netherlands, researchers found that those with the chromosomal disorder were on average twice as likely as their typically developing peers to be overweight or obese.

Starting at age 4, about a quarter of the children with Down syndrome studied were overweight, researchers report in the journal Pediatrics this week. That percentage remained consistent among older kids with the disorder as well.

Notably, researchers found a dramatic increase between the ages of 2 and 6 in the number of kids with Down syndrome who were overweight, a trend that was not as significant among typically developing kids. The rise occurred even among those with the disorder who were otherwise healthy.

It is unclear whether there are underlying biological factors making people with Down syndrome more likely to be overweight or purely lifestyle considerations at play, the study indicates, but researchers called the prevalence of kids who were overweight or obese “alarming.”

“Health care professionals should be aware of the risk … and should ensure that growth is monitored regularly in all children with (Down syndrome), thus enabling early detection of inappropriate weight gain and starting appropriate interventions where necessary,” researchers wrote.

Similarly high rates of obesity in children with special needs in the United States were reported last year. Domestically, researchers with the federal Health Resources and Services Administration found that more than 36 percent of kids ages 10 to 17 with special needs were overweight or obese compared to about 30 percent of other children.

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