Metabolic Syndrome in Overweight Hispanic Youth and the Role of Insulin Sensitivity

Abstract

Source: Cruz ML, Weigensberg MJ, Huang TTK, et al. The metabolic syndrome in overweight Hispanic youth and the role of insulin sensitivity. J Clin Endocrinol Metab. 2004;89:108–113.The longitudinal Study of Latino Adolescents at Risk for Diabetes (SOLAR Diabetes Project) based at the University of Southern California, Los Angeles, explores risk factors for the development of type 2 diabetes mellitus. This study focused on a subgroup of that population in an effort to establish the prevalence of the metabolic syndrome in overweight Hispanic youth and to evaluate the role of insulin sensitivity in the metabolic syndrome. The authors enrolled 126 overweight 8- to 13-year-old patients representing both sexes at various stages of puberty. Inclusion criteria included: 1) Hispanic ethnicity; 2) family history for type 2 diabetes in a parent, grandparent, or sibling; 3) body mass index of at least 85th percentile; and 4) absence of diabetes as documented by an oral glucose tolerance test. In the absence of a current definition of the metabolic syndrome in children, the authors defined metabolic syndrome as the presence of at least 3 of the following abnormalities:Ninety percent of these subjects had at least 1 component of the metabolic syndrome. Low HDL occurred in 67% of subjects, central obesity in 62%, impaired glucose tolerance in 27%, high triglyceride level in 26%, high systolic blood pressure in 22%, and high diastolic blood pressure in 4%. The presence of 1, 2, or 3 or more abnormalities associated with the metabolic syndrome occurred in 22%, 38%, and 30%, respectively. Approximately 10% of children had 4 or 5 metabolic syndrome features. More features of the metabolic syndrome were seen in post-pubertal compared to pre- and pubertal children, although the difference was not statistically significant. Boys also had a tendency toward a higher prevalence of features of metabolic syndrome compared to girls in the study, although this was statistically significant only for high triglycerides. Multiple linear regression analysis was used to assess the independent contribution of insulin sensitivity to the separate components of the metabolic syndrome. After adjustment for gender, age, total fat mass, and total lean mass, insulin sensitivity was shown to be positively related to HDL cholesterol and negatively related to triglycerides and systolic and diastolic blood pressure. In general, insulin sensitivity decreased as the number of components of the metabolic syndrome increased (P<.001). The authors conclude that overweight Hispanic youths with a family history of type 2 diabetes are at increased risk for cardiovascular disease and type 2 diabetes. This risk seems to be related to decreased insulin sensitivity. Improving insulin sensitivity is critical for the prevention of chronic disease in this population.Prevalence of the metabolic syndrome among US adults participating in the National Health and Nutrition Examination Survey (NHANES) is 23.7%.1 Hispanics had the highest prevalence of the metabolic syndrome (31.9%). The increased prevalence of obesity in children has been directly correlated with the increase in the incidence of type 2 diabetes and impaired glucose tolerance. The relationship between obesity and diabetes is probably due to insulin resistance and its associated metabolic abnormalities. Prior to this article, the prevalence of metabolic syndrome among Hispanic children was unknown, as was an understanding of the relationship between insulin sensitivity and the features of metabolic syndrome.With the phenomenal rise in prevalence of obesity among children and adolescents, particularly those of Hispanic origin, these authors have now established diagnostic criteria for the metabolic syndrome in overweight Hispanic youths. Increased prevalence of central obesity, low HDL, high triglyceride level, hypertension, and impaired glucose tolerance are cause for serious concern in this patient population. It is alarming to note that most of these children had at least 1 component of the metabolic syndrome, and that 10% had 4 or 5 components. By improving insulin sensitivity in these individuals, the risk of developing cardiovascular disease and type 2 diabetes may potentially be reduced. Recently, other researchers studied children who were not of Hispanic origin and showed that insulin resistance and obesity are early signs of metabolic syndrome in children.2 That study also showed that children who had at least 1 parent with metabolic syndrome were more likely to have signs of insulin resistance, including lower glucose disposal rates and higher fasting insulin.These 2 studies, in addition to reports by other researchers, 3–6 focuses attention on the consequences of obesity in children of all ethnic backgrounds. Pediatricians should make it their responsibility to educate parents that the prevention of childhood obesity is absolutely necessary to ensure the future health of their children. (See also this issue of AAP Grand Rounds, Fitness Lessens Effects of Metabolic Syndrome in Adults)