12/23/2013 08:26 am ET

Obese Children Have Higher Cortisol Stress Hormone Levels: Study

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Levels of the stress hormone cortisol seem to be higher in obese children than their non-obese peers, according to a small new study.

Researchers from the Erasmus MC-Sophia Children's Hospital in the Netherlands examined levels of cortisol from hair samples taken from 20 obese children (15 girls and five boys) and 20 normal weight children (15 girls and five boys), all of whom were between the ages of 8 and 12. None of the children had any chronic diseases, though three of the obese children had metabolic syndrome.

The obese children had an average cortisol concentration of 25 pictograms for each milligram of scalp hair. Meanwhile, the normal weight children had an average cortisol concentration of 17 pictograms for each milligram of hair. (Researchers noted that the cortisol concentrations found in these hair samples are indicative of cortisol exposure over about a month.)

"We were surprised to find obese children, as young as age 8, already had elevated cortisol levels," study researcher Dr. Erica van den Akker, M.D., Ph.D., said in a statement. "By analyzing children's scalp hair, we were able to confirm high cortisol levels persisted over time."

However, the findings do not explain whether obese children experience more stress than their normal-weight peers, or if obese children handle stress hormones differently -- more research is needed to determine the meaning behind the association, researchers said.

The new findings are published in the Journal of Clinical Endocrinology & Metabolism.

While not all stress is bad -- acute stress improves alertness and cognitive performance, for instance -- chronic stress has been linked with a number of health problems, including weight gain, heart disease, digestion problems, depression and anxiety, according to the Mayo Clinic.