SAN FRANCISCO — As early as age 6, obese children have larger fat cells, and there are more of them, compared with their skinny peers, researchers report.
Based on an analysis of samples from obese vs lean infants to 18-year-olds, Antje Körner, MD, from the Pediatric Research Center, University of Leipzig, Germany, and colleagues found that obese children with enlarged fat cells are also more likely to already have insulin resistance, she told the American Diabetes Association (ADA) 2014 Scientific Sessions.
"I wasn't surprised that we did find changes in the adipose tissue in these [obese] children," Dr. Körner told Medscape Medical News. "I was surprised that we saw [changes such as those in inflammatory markers] that early," she said. The message is that " 'chubby fat' [may be] appealing in children, but this excess body fat may already be detrimental" for their health. Moreover, these harmful changes in adipose cells in young children may persist for decades, she noted.
"This research emphasizes the importance of preventing pediatric obesity, [since it shows that] pathological changes associated with obesity are already present early in life," session moderator Maria Jose Redondo, MD, assistant professor of pediatrics, Baylor College of Medicine, Houston, Texas, told Medscape Medical News.
More, Larger Fat Cells in Chubby Children
Dr. Körner explained that the prevalence of obesity in children is rising, and she and her colleagues hypothesize that negative changes in fat cells also begin in childhood.
To investigate the relationship between adipose tissue biology and metabolic markers in obese vs lean children, they obtained fat tissue and blood samples from 106 lean children and 65 obese children who were undergoing surgery at their center.
About 60% of the children were girls. The lean children had a mean age of 7.6 years, whereas the obese children had a mean age of 11.4 years.
The lean children had a mean body mass index standard deviation score (BMI SDS) of -0.34, and the obese children had a mean BMI SDS of 2.29 (which is equivalent to a BMI of 30 kg/m2 at 19 years). Thinness is defined as less than -2SD, based on World Health Organization criteria, while obesity is defined as greater than +2SD.
The number of fat cells was more than 2-fold higher and the size of the fat cells was 17% larger in the fat tissue samples from the obese children compared with the samples from the lean children.
Looking at the adipose tissue under the microscope, the researchers found that obesity-associated dysfunction occurs early in life. They identified macrophages — which indicate the presence of inflammation — typically surrounding dead or dying fat cells and forming crownlike structures more often in the samples from the obese children. There were twice as many macrophages per 100 adipocytes in the tissue samples from the obese children as in those from the lean children.
"Our research shows that obese children start to have not only more but also larger adipocytes, or fat cells, at a very young age and that this is associated with increased inflammation and is linked to impaired metabolic function," Dr. Körner summarized.
To determine whether the obese children really go on to develop diabetes would require long-term studies, which are not available, she cautioned.
However, "what we do see clinically, be it high levels of homeostasis model assessment of insulin resistance [HOMA-IR] or high levels of circulating markers of inflammation like high-sensitivity C-reactive protein [hs-CRP] [has been shown to] often lead to overt diabetes in later years," she concluded.
This work was supported by the German Research Council (DFG) and the Federal Ministry of Education and Research (BMBF). Dr. Körner has reported no relevant financial relationships.
American Diabetes Association 2014 Scientific Sessions; June 15, 2014. Abstract 159-OR
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Cite this: Obese Kids Have Many Large Fat Cells, Ups Risk for Diabetes - Medscape - Jun 30, 2014.