Insulin resistance syndrome in childhood: associations of the euglycemic insulin clamp and fasting insulin with fatness and other risk factors.

OBJECTIVE: Our objective was to describe in children the relation of fatness and insulin resistance to the risk factors associated with the insulin resistance syndrome and to compare fasting insulin with the euglycemic insulin clamp as a measure of insulin resistance in children. STUDY DESIGN: This was a random selection of participants after blood pressure screening of 12,043 students in the fifth through eighth grades. Euglycemic insulin clamp studies with an insulin infusion rate of 1 mU/kg/min and a variable infusion of 20% glucose to maintain euglycemia, that is, plasma glucose at 5.6 mmol/L. Insulin sensitivity (M(lbm)) is defined as the amount of glucose required to maintain euglycemia (milligrams of glucose infused per kilogram lean body mass per minute). RESULTS: Body mass index was significantly correlated with fasting insulin and significantly inversely correlated with M(lbm). Fasting insulin was significantly correlated with systolic blood pressure in both sexes, all lipids, except high-density lipoprotein-cholesterol in males and triglycerides and high-density lipoprotein-cholesterol in females, but after adjustment was done for body mass index, it was significantly related only to triglycerides. M(lbm) was significantly correlated only with triglycerides and high-density lipoprotein-cholesterol, and this did not change after adjustment was done for body mass index. A clustering effect for the risk factors was seen in children in the lowest quartile of M(lbm) (highest degree of insulin resistance) compared with children in the highest quartile of M(lbm) (lowest degree of insulin resistance). CONCLUSIONS: As defined by M(lbm), there is an early association of insulin resistance, independent of body fat, with the risk factors. There is a significant relation between fasting insulin, as an estimate of insulin resistance, and the risk factors, but this is significantly influenced by body fatness. The clustering of risk factors according to level of M(lbm) suggests that adult cardiovascular disease is more likely to develop in children with the greatest degree of insulin resistance.

Secular trends of blood pressure and body size in a multi-ethnic adolescent population: 1986 to 1996.

OBJECTIVES: To determine the levels and time trends of blood pressure and body size in a healthy population of youth. STUDY DESIGN: Minneapolis, Minnesota, fifth through eighth grade public school children (aged 10 to 14 years) were surveyed in 1986 and 1996. Blood pressure, height, and weight were measured by technicians trained to the same rigorous protocol at each time period, and comparisons were made between the 2 groups (1986 and 1996). RESULTS: In 1986 and 1996, 8222 and 10,241 children, respectively, were measured with participation rates of over 93%. African American, Hispanic, Native American, Asian, and non-Hispanic white groups were all represented. Systolic blood pressure was significantly higher and diastolic blood pressure lower in 1996 than in 1986 in all ethnic and gender groups. Weight and body mass index (wt/ht2) were significantly higher in all groups in 1996. Adjustment for body size largely eliminated the systolic blood pressure differences but had no effect on measured diastolic blood pressure. CONCLUSIONS: Body size and systolic blood pressure are rising among school children. Weight and body mass index show substantial increases over 10 years (1986-1996). Diastolic blood pressure fell for unclear reasons. These changes may have future health implications for cardiovascular disease, as these youth move into adulthood.

Insulin response in a triethnic population: effects of sex, ethnic origin, and body fat. Miami Community Health Study.

OBJECTIVE: To assess sex and ethnic differences in hyperinsulinemia/insulin resistance and to examine the impact of percent body fat on such differences. RESEARCH DESIGN AND METHODS: A cross-sectional epidemiological study was performed in a normoglycemic population of African-Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic whites (n = 207) who resided in Dade County, Florida, from 1990 to 1995. The insulin area under the curve (AUC) in response to a standard 75-g oral glucose tolerance test (OGTT) was used as an indicator of hyperinsulinemia/insulin resistance. Analysis of covariance was performed to compare sex and ethnic differences in the insulin AUC. Multiple linear regression was used to evaluate the independent correlates of the insulin AUC. RESULTS: After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.001). African-Americans and Cuban-Americans each had a significantly higher insulin AUC than did non-Hispanic white participants (P = 0.01). Alcohol consumption was inversely related to AUC (P = 0.04). CONCLUSIONS: Despite the greater percentage of body fat in women, the insulin AUC was similar in women and men. After adjustment for the sex difference in percent body fat, women displayed a lower insulin AUC than did men, indicating enhanced insulin sensitivity. These differences by sex and ethnicity in insulin resistance are consistent with established differences in heart-disease risk (i.e., higher in men and African-Americans) and suggest that hyperinsulinemia/insulin resistance may partly underlie such differences.

South Florida Program on Aging and Health. Assessing the prevalence of Alzheimer's disease in three ethnic groups.

The South Florida Program on Aging and Health was initiated in 1992 with the aim to assess physical and mental health of the elderly in Dade County and provide a basis for public health policy. This report describes the methodology applied in the study and preliminary screening results in a probability sample of 2,400 African American, Cuban American and white non-Hispanic American elderly men and women. Of 2,013 participants screened by May 1995, 11.5% had cognitive impairment. An increase in prevalence from 4-7% to 25-36% with advancing age was found among men and women of each group, from the youngest (65-74) to the oldest (85+ years). Male and female prevalences were similar but vary by ethnic group and age.

Blood pressure nomograms for children and adolescents, by height, sex, and age, in the United States.

Because height is a more appropriate index of maturation than weight for use with normative blood pressure (BP) data, we developed normative BP levels for children, by sex, while accounting for age and height simultaneously. Eight U.S. studies used in the Report of the Second Task Force on Blood Pressure Control in Children and one additional study of BP in U.S. children were reanalyzed to develop age-sex-height-specific values for normative BP values among 56,108 children, aged 1 to 17 years, seen at 76,018 visits. Height percentiles were computed on the basis of standard National Center for Health Statistics growth charts. When height is taken into account, more short children (10th age-sex-specific height percentile) and fewer tall children (90th age-sex-specific height percentile) are likely to be classified as hypertensive than when the current age-sex-specific percentiles of BP alone are used. Tables are provided for boys and girls separately, by single year of age (1 to 17 years) and by the 90th and 95th percentiles of systolic blood pressure and diastolic blood pressure (fifth phase of Korotkoff sounds) for selected age-sex-specific height percentiles based on standard U.S. growth charts.

Prevalence of "significant" hypertension in junior high school-aged children: the Children and Adolescent Blood Pressure Program.

Blood pressure (BP) data obtained during a BP screening program were analyzed to determine the prevalence of "significant" hypertension, defined by the Second National Heart, Lung, and Blood Institute Task Force on Blood Pressure Control in Children-1987 as the level of BP above which medical evaluation and intervention are recommended. In 14,686 black and white St. Paul and Minneapolis schoolchildren aged 10 to 15 years, BP was measured twice during an initial screening examination. Children with systolic BP in the upper 30 percentiles of distribution after the initial screening had their BP remeasured two additional times at a rescreening examination. The prevalence of significant hypertension was determined according to BP criteria established by the Task Force report. After the two screening BP measurements were averaged, significant systolic hypertension was found in 1.0%, significant diastolic hypertension in 3.5%, and significant systolic or diastolic hypertension, or both, in 4.2% of the students. After the rescreening examination, the percentage of students remaining with significant hypertension was reduced to 0.3% for systolic, 0.8% for diastolic, and 1.1% for systolic or diastolic hypertension, or both. These results show that significant hypertension is uncommon in pre-high-school students and confirm the need for repeated BP measurements to make an accurate diagnosis of hypertension. However, the results should not detract from current recommendations to monitor BP in children on a yearly basis to detect longitudinal BP tracking patterns that may be consistent with early essential hypertension.