While there is currently no consensus regarding which of several definitions of metabolic syndrome is best applied to children, it may be more helpful to focus on the organizational framework of the syndrome in order to identify youth with cardiometabolic risk factor clustering.

 

Approximately 17% of children aged 2 to 19 in the United States are obese. As obesity rates increase, so too do rates of multiple cardiovascular and diabetes risk factors, such as hypertension, abnormal cholesterol, and hyperglycemia. In adults, metabolic syndrome—which is predictive of developing cardiovascular disease and type 2 diabetes—is defined as having at least three cardiometabolic risk factors among hypertension, central adiposity, increased triglycerides, decreased HDL-cholesterol, and hyperglycemia, says Sheela N. Magge, MD, MSCE. “Multiple definitions for metabolic syndrome in youth have been proposed, and questions have been raised regarding whether the concept of the metabolic syndrome is useful during childhood,” she explains. “However, the many children who are obese and overweight could face chronic health problems, such as heart disease and type 2 diabetes, decades earlier than previous generations, potentially coming with significant public health implications. Given limited resources to treat pediatric obesity, it is useful to identify those children who are at particularly increased cardiometabolic risk.”

 

Identifying At-Risk Youth

With the belief that rather than focusing on whether a child fits a particular metabolic syndrome definition or a particular risk factor cut-point, clinicians should use the organizational framework of the metabolic syndrome to identify youth with cardiometabolic risk factor clustering, Dr. Magge and colleagues authored a clinical report published in Pediatrics. “This clustering of cardiometabolic risk factors can help identify youth with increased risk for cardiovascular disease and diabetes,” she says. “In fact, to address the major metabolic syndrome-associated cardiometabolic risks during childhood, pediatricians should screen for and treat obesity, glucose abnormalities, hypertension, and dyslipidemia.  Identification of children with multiple risk factors, or risk factor clustering, enables pediatricians to identify youth at the greatest cardiometabolic risk, in order to target resources for focused interventions. It is also important to identify and treat comorbid conditions, such as non-alcoholic fatty liver disease, mental health problems, polycystic ovarian syndrome and obstructive sleep apnea. Clinicians should screen for these conditions, and treat and/or refer to specialists, as needed.”

Metabolic syndrome originates from insulin resistance associated with obesity, explains Dr. Magge (Figure). This insulin resistance leads to increased free fatty acid release, and to metabolic dyslipidemia and ectopic fat deposition. Adipose tissue dysfunction results, leading to adipocytokine release and then a state of low-grade inflammation results, with secretion of inflammatory factors and acute phase reactants. Thus, insulin resistance, ectopic fat deposition, and inflammation are all key pathophysiologic components of the metabolic syndrome.”

 

Important Considerations

Dr. Magge notes that there is currently no consensus regarding which particular definition of metabolic syndrome is best in children. Additionally, metabolic syndrome during childhood is often not stable, with children meeting the definition at a given point in time but not meeting it a few years later, or vice versa. “There are also racial and ethnic differences in many of the criterion risk factors of metabolic syndrome,” adds Dr. Magge. “For many of the risk factors, the risk is on a continuum. Rather than focus on a particular cut-point to fit a definition, it makes more sense to screen children for the risk factors. Children with clustering of multiple risk factors are at increased cardiometabolic risk, so these children can be targeted for focused interventions. Other than weight loss through improved nutrition and increased physical exercise, there is no other treatment for metabolic syndrome as a whole. The individual risk factor abnormalities must be treated. Development of these chronic conditions during childhood may lead to significant morbidity and mortality during what should be peak productive years. Clinicians must screen and treat obesity and its complications as early as possible.”

References

Magge S, Goodman E, Armstrong S. The metabolic syndrome in children and adolescents: shifting the focus to cardiometabolic risk factor clustering. Pediatrics. 2017, July 24. [ePub ahead of print]. Available at http://pediatrics.aappublications.org/content/early/2017/07/19/peds.2017-1603.

Laaksonen D, Lakka H, Niskanen L, et al. Metabolic syndrome and development of diabetes mellitus: application and validation of recently suggested definitions of the metabolic syndrome in a prospective cohort study. Am J Epidemiol. 2002;156:1070-1077.

Malik S, Wong N, Franklin S, et al. Impact of the metabolic syndrome on mortality from coronary heart disease, cardiovascular disease, and all causes in United States adults. Circulation. 2004;110:1245-1250.

Zimmet P, Alberti K, Kaufman F, et al. The metabolic syndrome in children and adolescents – an IDF consensus report. Pediatr Diabetes. 2007;8:299-306.