Fasting and 2-hour plasma glucose and insulin: relationship with risk factors for cardiovascular disease in overweight nondiabetic children

OBJECTIVE

To determine whether elevated fasting or 2-h plasma glucose and/or insulin better reflects the presence of cardiovascular disease (CVD) risk markers in an overweight pediatric population with normal glucose tolerance.

RESEARCH DESIGN AND METHODS

A total of 151 overweight youths (8–17 years old) were evaluated with oral glucose tolerance tests and measurement of CVD risk factors. The study population was categorized according to quartiles of fasting and 2-h glucose and insulin levels. ANCOVA, adjusted for age, sex, race, Tanner stage, and percent body fat (measured by dual-energy X-ray absorptiometry), was used to compare metabolic variables between the quartiles of glucose and insulin groups.

RESULTS

Increasing quartiles of fasting and 2-h insulin were associated with increasing CVD risk factors. Glucose quartiles on the other hand, either fasting or at 2 h, were not.

CONCLUSIONS

These data suggest that hyperinsulinemia may be the earliest and/or primary metabolic alteration in childhood associated with risk markers for CVD. Prospective studies are needed.The prevalence of childhood overweight is increasing relentlessly (1–2). An increase in the rates of pre-diabetes and type 2 diabetes seems to follow the upward trend of obesity (3). Longitudinal studies in adults demonstrate that cardiovascular disease (CVD) changes are established before a diagnosis of diabetes is made and correlate better with 2-h glucose levels (4–5). Guidelines on diabetes and CVD from the European Society of Cardiology and the European Association for the Study of Diabetes have summarized that 2-h glucose provides better information about risk for CVD than fasting glucose and predicts increased cardiovascular risk in subjects with normal fasting glucose levels (6).Meta-analyses of prospective data from 11 populations have shown that hyperinsulinemia, defined by the highest quartile cutoff for fasting insulin, was associated with cardiovascular mortality independently of other risk factors (7). A review of 19 Western prospective studies showed that the odds ratio (OR) for coronary heart disease for raised fasting insulin as well as nonfasting insulin were more modest than previously suspected (OR 1.12 [95% CI 0.98–1.28] and 1.35 [1.14–1.60], respectively) (8).No studies have evaluated whether a fasting or 2-h glucose and/or insulin value reflects better the presence of CVD risk factors in overweight children with normal glucose tolerance. The purpose of this investigation was to assess the relationship between glucose and insulin quartiles and CVD risk factors in an overweight pediatric population.