Evaluation of the Insulin Resistance Syndrome in 5- to 10-Year-Old Overweight/Obese African-American Children

Abstract

OBJECTIVE -To characterize the insulin sensitivity of overweight and obese 5-to 10-yearold (Tanner stage 1-3) African-American children screened for participation in a diabetes prevention study and to identify the association of insulin sensitivity with obesity, hyperlipidemia, and hypertension.RESEARCH DESIGN AND METHODS -Measures of insulin resistance (homeostasis model assessment) and insulin sensitivity (Matsuda and DeFronzo's whole-body insulin sensitivity) were calculated from a 2-h oral glucose tolerance test in 137 African-American children recruited into a diabetes prevention study. Measures of lipids (LDL, HDL, total cholesterol, and triglycerides), blood pressure, and body composition were obtained for a subset of the children.RESULTS -In response to a glucose challenge, girls and older and heavier children produced significantly more insulin. As BMI increased, there was a statistically significant decrease in insulin sensitivity, particularly in girls. Insulin sensitivity was inversely correlated with increases in blood pressure, triglycerides, subcutaneous fat, the percentage of total body fat, and Tanner stage, but it was not correlated with LDL and HDL.CONCLUSIONS -Reduced insulin sensitivity and the cluster of risk factors known as the insulin resistance syndrome (IRS) are already apparent in these overweight African-American children. Young African-American girls, in particular, already show evidence of hyperinsulinemia in response to a glucose load, suggesting that the early stages of metabolic decompensation that lead to type 2 diabetes are already occurring. Monitoring of those risk factors known to be part of IRS should become part of routine medical care for overweight or obese African-American children. Diabetes Care 24:1359 -1364, 2001T he prevalence of overweight/obesity is increasing in children, as is the diagnosis of type 2 diabetes (1-3). Obesity and insulin resistance are known risk factors for the development of type 2 diabetes in adults (4). For adults, type 2 diabetes and obesity are more prevalent in the African-American population than in European-Americans, especially among African-American women (5). Minority populations have also seen the greatest increase in childhood and adolescent diagnoses of type 2 diabetes (6).Studies in adults have consistently shown insulin resistance and hyperinsulinemia to be strong predictors of the development of type 2 diabetes (7). In addition to insulin resistance and ␤-cell dysfunction, obesity (specifically central adiposity [8]), dyslipidemia (9 -10), and genetic predisposition (11) are risk factors for the development of impaired glucose tolerance and type 2 diabetes in adults.The clustering of insulin resistance, obesity, hypertension, dyslipidemia, and atherosclerosis has been referred to as the insulin resistance syndrome (IRS), the metabolic syndrome, or syndrome X (12). Increasing rates of type 2 diabetes in the pediatric population suggest the need to explore the development of insulin resistance and other risk factors (13) for type ...

The gender insulin hypothesis: why girls are born lighter than boys, and the implications for insulin resistance

“…[15][16][17][18][19][20][21][22][23] This sex difference in insulin resistance has usually been attributed to differences in adiposity or pubertal stage, but in studies which have adjusted for these factors 15,18 a residual difference remains which has not been explained. We have shown that girls are substantially (B33%) more insulin resistant than boys at 5 years 24 and in the years leading up to puberty.…”

Lifecourse weight patterns and adult-onset diabetes: the Glasgow Alumni and British Women's Heart and Health studies

“…[1][2][3] Being overweight or obese in adult life also increases the risk of these conditions 4,5 and there is accumulating evidence indicating that weight in pre-adult and early adult life also affect later adult-onset conditions. 6,7 However, among participants in the US Nurses Health Study body mass index, based on self-report of weight and height in a questionnaire when the participants were aged 30-55, was strongly associated with diabetes risk during eight years of follow-up, but body mass index when the nurses were 18 years of age (based on retrospective report of their earlier weight by the nurses at the baseline examination) was only weakly associated with future risk of diabetes, with this risk attenuating to the null with adjustment for later body mass index. 8 Taken together, these observations imply that people who subsequently develop diabetes have a different growth trajectory or excess weight gain over the lifecourse in comparison with the rest of the population.…”

The Relationship between Changes in Weight Status and Insulin Resistance in Youth

“…While numerous cross-sectional studies have noted positive associations ( r = 0.31 to 0.85) between insulin and measures of adiposity in youth, the relationships between change in weight status and change in IR have not been examined thoroughly [2–8]. The few longitudinal studies of youth have consistently reported that change in weight is positively associated with change in insulin or IR and negatively associated with insulin sensitivity [9–11].…”