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BMI is not an equivalent measure of the percent body fat for each race-sex group. When BMI is used as a measure of body fatness in a research or clinical setting, particularly when comparisons are made across race and gender, it may be important to consider the maturation stage, race, gender, and distribution of body fat in the interpretation of the results.

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Background-Obesity is associated with increased risk of cardiovascular disease in adults and less favorable cardiovascular risk factor status in children and adolescents. In adults, fat distribution has been shown to be related to lipid and lipoprotein concentrations, blood pressure levels, and left ventricular mass. These relationships have not been extensively studied in young subjects. Methods and Results-This was a cross-sectional study of 127 children and adolescents 9 to 17 years of age. Dual-energy x-ray absorptiometry was used to measure total and regional fat mass. The dependent variables were fasting lipid and lipoprotein concentrations, systolic and diastolic blood pressures, and left ventricular mass. There were significant (PϽ0.05) univariate correlations between fat distribution and log triglycerides (rϭ0.27), log HDL cholesterol (rϭϪ0.23), systolic blood pressure (rϭ0.26), and left ventricular mass (rϭ0.37). Multiple regression analysis showed that the significant independent correlates for triglycerides and HDL cholesterol were age and fat distribution; for systolic blood pressure, height and fat distribution; and for left ventricular mass, height, race, sex, and fat distribution. Conclusions-These results demonstrate that fat distribution is a more important independent correlate of cardiovascular risk factors than percent body fat in children and adolescents.

Background-Left ventricular (LV) hypertrophy has been established as an independent risk factor for cardiovascular disease in adults. Recent research has refined this relationship by determining a cutpoint of 51 g/m 2.7 for LV mass index indicative of increased risk and defining LV geometric patterns that are associated with increased risk. The purpose of this study was to evaluate severe LV hypertrophy and LV geometry in children and adolescents with essential hypertension. Methods and Results-A cross-sectional study of young patients (nϭ130) with persistent blood pressure elevation above the 90th percentile was conducted. Nineteen patients (14%) had LV mass greater than the 99th percentile; 11 of these were also above the adult cutpoint of 51 g/m 2.7 . Males, subjects with greater body mass index, and those who had lower heart rate at maximum exercise were at significantly (PϽ.05) higher risk of severe LV hypertrophy. In addition, 22 patients (17%) had concentric LV hypertrophy, a geometric pattern that is associated with increased risk of cardiovascular disease in adults. Seven patients had LV mass index above the cutpoint and concentric hypertrophy. No consistent significant determinants of LV geometry were identified in these children and adolescents with hypertension. Conclusions-Severe LV hypertrophy and abnormal LV geometry are relatively prevalent in young patients with essential hypertension. These findings suggest that these patients may be at risk for future cardiovascular disease and underscore the importance of recognition and treatment of blood pressure elevation in children and adolescents. Weight loss is an important component of therapy in young patients with essential hypertension who are overweight. (Circulation. 1998;97:1907-1911.)

IntroductionAdults with obesity or obesity-related type 2 diabetes (T2DM) are at higher risk for stroke and myocardial infarction.[1] Increased arterial stiffness is one mechanism that may explain this finding as vascular dysfunction is linked to higher rates for cardiovascular (CV) diseases [2] and arterial abnormalities are more prevalent in overweight and diabetic persons.[3] Therefore, we sought to determine if arterial stiffness is increased in youth with obesity or T2DM as compared to lean controls. Methods Study PopulationA total of 670 youth were examined as part of an ongoing study of the cardiac and vascular effects of obesity and T2DM (62% non-Caucasian, 35% male) conducted at a single site. Youth age 10 to 24 years with a diagnosis of T2DM (N = 195) made by the primary provider, who were islet cell antibody negative (glutamic acid decarboxylase, ICA 512, insulin autoantibodies), had no evidence of other specific type of diabetes, and who were non-insulin requiring in the basal state to prevent diabetic ketoacidosis were eligible. Most were recruited from the Cincinnati Children's Hospital diabetes clinic. Average duration of diabetes was 3.6 ± 2.6 years. The majority of the T2DM subjects were overweight or obese (93% had BMI ≥ 85 th percentile, 80% were actually ≥ 95th percentile for age and sex). Each diabetic subject was matched to at least one lean (L = 231, < 85 th percentile for BMI) and obese control (O = 234, > 95 th percentile) [4] by age, race and gender. All O subjects underwent a 2-hour oral glucose tolerance test to rule out sub-clinical T2DM according to ADA guidelines.[5] Pregnant females were excluded from the study.Prior to enrollment in the study, written informed consent was obtained from subjects ≥18 years old or the parent or guardian for subjects < 18 years old. Written assent was also obtained for subjects < 18 years old according to the guidelines established by the Institutional Review Board at Cincinnati Children's Hospital. Dual-energy X-ray Absorptiometry (DXA) was performed with a Hologic 4500A (Hologic, Bedford, Mass.). Standards correlating X-ray beam attenuation to amount of lean and fat mass have been developed and validated against the hydrodensitometry method, which has previously been established as the most valid measurement of lean body mass and fat mass.[7] Percent body fat was calculated as total body fat mass divided by total body mass times 100. To determine fat distribution, android (abdominal) to gynoid (hip) ratio was calculated as sum of fat content in the subscapular (neck to waist) plus waist area (to iliac crest), divided by the hip and thigh regions. [7] In previous studies, the coefficients of variation for regional measurements are less than 5%.Physical activity was assessed using an Actical accelerometer (Phillips Respironics) worn on the waist during waking hours over a 7 day period. This device is an omni-directional detector that provides counts of movement in all directions.[8] Counts of activity per minute worn were calculated and averaged ove...

Hypertension (HT) is associated with increased LVM and carotid intima-media thickness (cIMT) which predict cardiovascular (CV) events in adults. Whether target organ damage (TOD) is found in prehypertensive youth (PreHT) is not known. We measured BMI, BP, fasting glucose, insulin, lipids and CRP, LVM/ht2.7 (LVMI), diastolic function, cIMT, carotid stiffness, augmentation index (AIx), brachial artery distensibility (BrachD), pulse wave velocity (PWV), in 723 subjects 10–23 yrs (29% type 2 diabetes mellitus, T2DM). Subjects were stratified by BP level (normotensive: NT=531, PreHT=65, HT=127). Adiposity and CV risk factors worsened across BP group. There was a graded increase in cIMT, arterial stiffness, and LVMI and decrease in diastolic function from NT to PreHT to HT. In multivariable models adjusted for CV risk factors, status as PreHT or HT remained an independent determinant of TOD for LVM, diastolic function, internal cIMT, carotid and arterial stiffness. PreHT is associated with CV TOD in adolescents and young adults.