Reinventing Childhood Metabolic Syndrome Testing
A high school football player came to see UVA pediatric endocrinologist Mark DeBoer, MD, after a knee injury took him out of the game and left him inactive. The boy had gained 20 pounds, which pushed his weight to 240 and his BMI to 34. The boy’s mother and paternal grandfather were both diabetic, and his mom wanted to know if he was at an increased risk for diabetes as well.
For DeBoer, it was both a heartbreaking and frustrating question. “Certainly, he was very likely to develop diabetes,” DeBoer says. “But we didn’t have tools that could really pinpoint his risk.”
DeBoer knew that the criteria used to determine whether his patient had metabolic syndrome (MetS) had a number of shortcomings. For one, the assessment tended to underestimate the risk of diabetes in certain racial and ethnic groups.
Experiences like this one motivated DeBoer and his colleague, Matthew Gurka, PhD, a biostatistician at the University of Florida, to take a new approach to MetS analysis. They developed a MetS Severity Score that is more specific in terms of gender, race and ethnicity, and can be used to assess risk over time.
“The roots of type 2 diabetes and cardiovascular disease start in childhood in many individuals, and by identifying children who are at risk, we can start turning this around by motivating children and their families to make lifestyle changes while there’s still time and improve their outcomes,” DeBoer says.
The Need for a New Measure
As you know, metabolic syndrome is a cluster of risk factors — central obesity, elevated glucose, hypertension, high triglycerides and low HDL cholesterol — that, when combined with genetic and lifestyle factors, are associated with insulin resistance and a greater risk of cardiovascular disease and diabetes. The traditional system for assessing MetS has cut-off points for each risk factor derived from the population in general, for instance a waist circumference that is above the 90th percentile. To be diagnosed with MetS, patients have to have abnormal readings in three of the five categories.
“This system raised an immediate question for us,” DeBoer says. “An individual just below the cut-off point in all five categories would have a similar risk profile as someone officially diagnosed with MetS.”
They also noted gender, racial and ethnic differences in how MetS manifests itself. DeBoer and Gurka found that African-Americans, and particularly African-American men, are less likely to have metabolic syndrome even though African-Americans are more prone than other groups to be diagnosed with diabetes and cardiovascular disease. One reason for this is that African-Americans are likely to have lower levels of triglycerides and higher levels of HDL cholesterol than the population in general.
The MetS Severity Score
Spurred on by these findings, DeBoer and Gurka began working on their own scoring system. “We wanted to make it gender-, race- and ethnicity-specific,” he says. “We also wanted to create a measure that would indicate the severity of your MetS, not just simply tell you whether you have it or not.”
Instead of placing equal weight on each of the five components of MetS, they used statistical techniques to determine which risk factors were more influential for specific groups. They discovered, for instance, that BMI was the most important consideration for African-American males. They used coefficients derived from these leading factors, combined with measured clinical values, to produce what DeBoer calls the MetS Severity Score, which represents standard deviation from the mean. All told, DeBoer and Gurka developed 12 uniquely weighted scoring systems for African-American, Hispanic and Caucasian males and females, children and adults.
DeBoer and Gurka then looked at long-term data to determine how well a MetS Severity Score derived in childhood predicts adult disease. They found that for every one-point increase in the MetS Severity Score in childhood, there was a three-fold increase in risk for developing diabetes in early adulthood and a 10-fold risk of developing cardiovascular disease.
DeBoer’s next step is to work with Gurka to develop risk thresholds — points at which clinicians should begin targeting individuals in each group for more intensive treatment. This will require DeBoer and Gurka to compile and analyze data from several long-term studies. DeBoer believes that they will have a threshold for adults within the next year and one for adolescents within the next two years.
“I would have loved to be able to tell the parent of that football player: ‘Here are the risks your child is facing if things continue the way they are,’” DeBoer says. “The MetS Severity Score will give physicians a tool to do exactly that.”
While there is still work to be done to apply this tool in a clinical setting, DeBoer encourages physicians to consider it a resource when evaluating young patients. “We are hopeful that this score can be used to assess the baseline risk for adolescents regarding metabolic syndrome and their risk for future disease,” DeBoer says. “Physicians may use it as a motivator for individuals to try to change their risk so that they may have a healthier diet, engage in more physical activity or get medication to reduce their metabolic syndrome severity and their future risk for disease.”
You can access the online MetS Severity Score calculator here.
Interpreting the MetS Severity Score
The score reveals how an adolescent’s risk for heart disease and diabetes compares to the general population. If all adolescents took the test, most would score between -2 (low risk) and +2 (high risk).
< 0 = Below-average risk
0 = Average risk
> 1 = Moderate risk
> 2 = High risk
It’s important that anyone who scores 1.0 or above take steps to reduce their risk through exercise and a healthier diet.
If you have questions about the MetS Severity Score or would like to refer a patient to the Pediatric Endocrinology Clinic at UVA Children’s Hospital, please contact Mark DeBoer.