Obesity in association with hypertension, elevated levels of triglycerides, reduced levels of high-density lipoprotein-cholesterol (HDL-C), insulin resistance, or glucose intolerance is a widely recognized constellation of risk factors for heart disease and type 2 diabetes known as the metabolic syndrome (MetS). Although the MetS has long been recognized as a precursor to cardiovascular disease and type 2 diabetes in adults (1
), the evidence for an increase in the prevalence of the MetS in US adolescents has been accumulating (4
). To address concerns about the growing prevalence of the MetS and to prevent the disease in adolescents, it is important to identify the high-risk children.
The implications of the MetS in children are more severe than in adults for at least two reasons. First, the morbidities associated with type 2 diabetes initiating in adolescence would result in many more decades of morbidity than in an adult. Second, an extended period of morbidity would certainly translate into higher medical costs over the course of a lifetime. A study that investigated healthcare utilization and costs associated with the MetS in three health plans in Seattle, WA, found that the average annual total costs between patients with the MetS and those without the MetS differed by a factor of 1.6 ($5732 vs. $3581) (7
). Furthermore, for those with the MetS who go on to develop type 2 diabetes, the costs were nearly twice that of prediabetic patients. Another study involving 4188 working adults in Michigan found that the health costs for employees with the MetS and associated diseases were nearly four-fold greater than those without the MetS and who were disease-free (8
Acanthosis nigricans (AN) may serve as a marker for identifying children at risk of developing the MetS. AN is a dermatologic condition characterized by hyperpigmentation, hyperkeratosis, and papillomatosis and is strongly associated with hyperinsulinemia (9
). The typical areas of involvement in AN include the posterior neck, the axilla, the elbows, and the knees, with the neck being involved 93 % – 99 % of the time (16
). In populations where traditional risk factors, such as obesity and a family history of diabetes are especially common, AN may aid in rapidly identifying a subgroup of individuals who are at an increased risk for future disease, particularly type 2 diabetes (18
). Although several studies have found AN to be an independent predictor of hyperinsulinemia (10
), others have not (20
The MetS in children is a cause for special concern because it is a well-established precursor of cardiovascular disease and type 2 diabetes in adults (22
). Only recently have attempts been made to characterize the MetS in the pediatric population (4
). Because data that track individuals from childhood to adulthood are limited, little is known about how well pediatric MetS predicts adult disease; however, the evidence of this sort is beginning to emerge. In a follow-up study of 771 children ages 6 – 19, the Princeton Lipid Research Clinics found that children with the clustering of the MetS risk factors were significantly more likely to have cardiovascular disease 25 years later when compared with their peers (27
). Franks et al. (28
) found from the longitudinal data for 1604 non-diabetic 5 – 19-year-old American-Indian children that the strategies targeting obesity, dysregulated glucose homeostasis, and low HDL during childhood support the prevention of type 2 diabetes. Recently, Nguyen et al. reported data from the Bogalusa Heart Study, which show that indicators of poor glucose homeostasis, such as plasma glucose and insulin levels and insulin resistance index [homeostasis model assessment-insulin resistance (HOMA-IR)] in childhood not only persisted into adulthood but also predicted who would develop adult prediabetes and type 2 diabetes (29
The main aim of the present study was to investigate the association between AN and the components of the MetS in school-aged children. To accomplish this goal, we enrolled students attending an urban elementary school in New Mexico and obtained their health history, anthropometric measures, and serum biomarkers of the MetS, which included glucose, insulin, triglyceride, and HDL-C. In addition, we collected demographic information that included age, sex, and race/ethnicity. These data were used to address several questions. First, we were interested in knowing the prevalence of AN in these children. Second, we wanted to compare the levels of biomarkers and cardiometabolic risks by body mass index (BMI) and AN status of the children. Specifically, we compared insulin levels, HOMA-IR, triglycerides, HDL-C, systolic blood pressure (SBP), and the clustering of these in children stratified by BMI and AN status.