Syndrome x in children: Influence of ethnicity and visceral fat

Syndrome X, the clustering of risk factors for cardiovascular disease, is r ecognized as an obesity-related health concern among adults. In particular, individuals with visceral (intra-abdominal) obesity are prone to developin g syndrome X. Although extremes of visceral fat have been detected in prepu bertal children, the extent to which visceral fat contributes to the develo pment of disease risk factors in children is not known. This review address es the occurrence of syndrome X and its antecedents in the pediatric popula tion, as well as two specific issues regarding syndrome X in children: the roles of ethnicity and visceral fat. The central feature to emerge from mos t studies is that basal and post-challenge insulin are significantly higher in African-American, Mexican-American, and Pima Indian children compared t o Caucasian children. Although these ethnic differences are independent of adiposity, adiposity is associated with greater insulin in all ethnic group s examined. Mexican-Americans have a higher lipid risk factor level, which is related to greater obesity, and African-Americans have lesser lipid-asso ciated risk, independent of obesity. African-American children may be more likely to develop type 2 diabetes due to obesity-independent hyperinsulinem ia and insulin resistance, but appear less predisposed to the obesity-relat ed clustering of risk factors associated with syndrome X. Mexican-American children may be more likely to develop syndrome X due to greater obesity-re lated hyperinsulinemia and dyslipidemia. Total body fat, rather than viscer al fat, appears be the primary determinant of insulin resistance prior to p uberty. However, visceral adipose tissue is uniquely related to both insuli n and lipid risk factors in children and adolescents, and thus may contribu te to the development of the early stages of syndrome X (C) 1999 Wiley-Liss , Inc.