Eating patterns and lipid levels in older adolescent girls

BACKGROUND AND AIMS

Few studies have evaluated the effects of food-based eating patterns on adolescent lipid levels. This study examines whether usual adolescent eating patterns (ages 9-17 years) predict lipid levels at 18-20 years of age.

METHODS AND RESULTS

This study uses previously collected data from the longitudinal NHLBI Growth and Health Study in which 2379 girls were enrolled at ages 9-10 years and followed for ten years. Food-based eating patterns were derived from multiple 3-day diet records. After adjusting for age, race, socioeconomic status, height, physical activity, and television viewing, girls with higher intakes of dairy, fruit and non-starchy vegetables had about a 40-50% reduced risk an LDL-C ≥ 170 mg/dL and non-HDL-C ≥ 145 mg/dL. Diets characterized by higher intakes of dairy and whole grains had similar benefits on TC and LDL-C. Girls consuming more fruits and non-starchy vegetables as well as more whole grains were much less likely to have high-risk lipid levels. Lean meat, poultry and fish when consumed in the context of other healthy eating patterns had no adverse effects on lipid levels in late adolescence. In fact when consumed with higher amounts of fruit and non-starchy vegetables, lean meat, poultry and fish had beneficial effects on HDL. Finally, dietary patterns that included more whole grains tended to be associated with lower TG levels.

CONCLUSION

Healthy childhood eating patterns characterized by higher intakes of a variety of fruits, vegetables, whole grains, dairy, lean meat, poultry and fish are important modifiable predictors of lipid levels in late adolescence.

Glucose control predicts 2-year change in lipid profile in youth with type 1 diabetes

OBJECTIVE

To test the hypothesis that a change in glycated hemoglobin (A1c) over a follow-up interval of approximately 2 years would be associated with concomitant changes in fasting lipids in individuals with type 1 diabetes (T1D).

STUDY DESIGN

All subjects with T1D diagnosed in 2002-2005 in the SEARCH for Diabetes in Youth study with at least 2 study visits ∼12 and ∼24 months after an initial visit were included (age at initial visit, 10.6 ± 4.1 years; 48% female; diabetes duration, 10 ± 7 months; 76% non-Hispanic white; A1c = 7.7% ± 1.4%). Longitudinal mixed models were fit to examine the relationship between change in A1c and change in lipid levels (total cholesterol [TC], high-density lipoprotein-cholesterol [HDL-c], low-density lipoprotein-cholesterol [LDL-c], log triglycerides [TG], and non-HDL-c) with adjustment for possible confounders.

RESULTS

Change in A1c over time was significantly associated with changes in TC, HDL-c, LDL-c, TG, and non-HDL-c over the range of A1c values. For example, for a person with an A1c of 10% and then a 2% decrease in A1c 2 years later (to 8%), the model predicted concomitant changes in TC (-0.29 mmol/L, -11.4 mg/dL), HDL-c (0.03 mmol/L, 1.3 mg/dL), LDL-c (-0.23 mmol/L, -9.0 mg/dL), and non-HDL-c (-0.32 mmol/L, -12.4 mg/dL) and an 8.5% decrease in TG (mmol/L).

CONCLUSIONS

Improved glucose control over a 2-year follow-up was associated with a more favorable lipid profile but may be insufficient to normalize lipids in dyslipidemic T1D youth needing to decrease lipids to goal.

Phylogeography of the Cape velvet worm (Onychophora: Peripatopsis capensis) reveals the impact of Pliocene/Pleistocene climatic oscillations on Afromontane forest in the Western Cape, South Africa

Habitat specialists such as soft-bodied invertebrates characterized by low dispersal capability and sensitivity to dehydration can be employed to examine biome histories. In this study, the Cape velvet worm (Peripatopsis capensis) was used to examine the impacts of climatic oscillations on historical Afromontane forest in the Western Cape, South Africa. Divergence time estimates suggest that the P. capensis species complex diverged during the Pliocene epoch. This period was characterized by dramatic climatic and topographical change. Subsequently, forest expansion and contraction cycles led to diversification within P. capensis. Increased levels of genetic differentiation were observed along a west-to-south-easterly trajectory because the south-eastern parts of the Cape Fold Mountain chain harbour larger, more stable fragments of forest patches, have more pronounced habitat heterogeneity and have historically received higher levels of rainfall. These results suggest the presence of three putative species within P. capensis, which are geographically discreet and genetically distinct.

Blood pressure elevation in long-term survivors of pediatric liver transplantation

As pediatric liver transplant (LT) recipients come of age, additional insight into long-term medical complications of immunosuppression is warranted. The aims of this study were to estimate the prevalence of elevated blood pressure (BP) in long-term survivors of pediatric LT using the data from the Studies in Pediatric Liver Transplantation (SPLIT) database and to identify predictive factors. Patients enrolled in the BP arm of the SPLIT cohort participated in the study. All patients were of at least 5 years but ≤10 years post-LT. Automated BP measurements were obtained at anniversary visits. BP measures were classified as normal, borderline or elevated according to standard criteria. Patients taking antihypertensive medications were classified as "elevated." Eight hundred and fifteen patients participated. The prevalence of elevated BP measurements 5 to 10 years post-LT was 17.5 to 27.5%. Of total 62.5% patients presented with at least one additional elevated BP at a later follow up visit. Multivariate analysis revealed the following parameters to be predictive of elevated BP: age at transplant, steroid use at last BP measurement and cGFR at last BP measurement. Pediatric LT patients show a high prevalence of elevated BP measurements 5 to 10 years following LT, which is related to age at LT, decreased cGFR and recent steroid use.

Screening and treatment of dyslipidemias in children and adolescents

BACKGROUND/AIMS

Cardiovascular disease is the most prominent cause of mortality worldwide. A key risk factor for atherosclerotic cardiovascular disease is the presence of dyslipidemia. Clinical approaches to evaluation and treatment of dyslipidemia in children and adolescents are presented.

METHODS

A review of published guidelines and presentation of illustrative cases.

RESULTS

Dyslipidemia is an important risk factor in early-stage atherosclerosis. Children and adolescents at high risk for dyslipidemia can be identified using a positive family history or the presence of other risk factors as a trigger. Once high-risk individuals are identified, primary treatment is lifestyle modification. In cases where low-density lipoprotein-cholesterol is high, pharmacologic intervention may be needed.

CONCLUSIONS

Screening of appropriate children and adolescents for dyslipidemia and treating those at high risk are important for the long-term prevention of cardiovascular disease.

The effects of obesity and type 2 diabetes mellitus on cardiac structure and function in adolescents and young adults

AIMS/HYPOTHESIS

We sought to evaluate the effects of obesity and obesity-related type 2 diabetes mellitus on cardiac geometry (remodelling) and systolic and diastolic function in adolescents and young adults.

METHODS

Cardiac structure and function were compared by echocardiography in participants who were lean, obese or obese with type 2 diabetes (obese diabetic), in a cross sectional study. Group differences were assessed using ANOVA. Independent determinants of cardiac outcome measures were evaluated with general linear models.

RESULTS

Adolescents with obesity and obesity-related type 2 diabetes were found to have abnormal cardiac geometry compared with lean controls (16% and 20% vs <1%, p < 0.05). These two groups also had increased systolic function. Diastolic function decreased from the lean to obese to obese diabetic groups with the lowest diastolic function observed in the obese diabetic group (p < 0.05). Regression analysis showed that group, BMI z score (BMIz), group × BMIz interaction and systolic BP z score (BPz) were significant determinants of cardiac structure, while group, BMIz, systolic BPz, age and fasting glucose were significant determinants of the diastolic function (all p < 0.05).

CONCLUSIONS/INTERPRETATION

Adolescents with obesity and obesity-related type 2 diabetes demonstrate changes in cardiac geometry consistent with cardiac remodelling. These two groups also demonstrate decreased diastolic function compared with lean controls, with the greatest decrease observed in those with type 2 diabetes. Adults with diastolic dysfunction are known to be at increased risk of progressing to heart failure. Therefore, our findings suggest that adolescents with obesity-related type 2 diabetes may be at increased risk of progressing to early heart failure compared with their obese and lean counterparts.

Association of insulin sensitivity to lipids across the lifespan in people with Type 1 diabetes

AIMS

Insulin resistance and dyslipidaemia both increase cardiovascular risk in Type 1 diabetes. However, little data exist on the associations of insulin resistance to lipids in Type 1 diabetes. Our objective was to explore the associations between insulin resistance (assessed by glucose infusion rate) and lipids in people with Type 1 diabetes and determine whether adiposity and/or average glycaemia influence these associations.

METHODS

Hyperinsulinaemic-euglycaemic clamp studies were performed in 60 subjects with Type 1 diabetes aged 12-19 years (age 15±2 years, 57% female, duration of diabetes 6.3±3.8 years, HbA(1c) 8.6±1.5%, IFCC=70 mmol/mol) and 40 subjects with Type 1 diabetes aged 27-61 years (age 45±9 years, 53% female, duration of diabetes 23±8 years, HbA(1c) 7.5±0.9%, IFCC=58 mmol/mol). Multiple linear regression models were fit to examine the association between glucose infusion rate and fasting lipid levels with adjustment for possible confounders.

RESULTS

Lower glucose infusion rate was significantly associated with lower levels of HDL cholesterol in youths with Type 1 diabetes and with higher levels of triglycerides and higher triglyceride/HDL ratio in both youths and adults. The magnitude of the associations between glucose infusion rate and lipid levels translate into interquartile differences of 0.098 mmol/l for HDL cholesterol, 0.17 mmol/l for triglycerides and 1.06 for triglycerides/HDL in the adolescents and 0.20 mmol/l for triglycerides and 1.01 for triglycerides/HDL in the adults. The associations were attenuated and no longer statistically significant by adjustment for adiposity among adults, while adjustment for HbA(1c) had a small effect in youths and adults.

CONCLUSIONS

Lower insulin sensitivity is associated with a more atherogenic lipid profile in both youths and adults with Type 1 diabetes.

Chromosomal polymorphisms in African vlei rats, Otomys irroratus (Muridae: Otomyini), detected by banding techniques and chromosome painting: inversions, centromeric shifts and diploid number variation

Pericentric inversions are important for evolutionary biology because of their potential role in speciation. They may result in reproductive isolation due to illegitimate pairing of homologues at meiosis which leads to the production of aneuploid gametes (containing deletions or duplications of chromosomal segments), and consequently mediate chromosomal divergence. In this study, we describe the prevalence of pericentric inversions in the African vlei rat, Otomys irroratus (OIR). The species is characterized by intraspecific chromosomal variation (2n = 23-32) across its distribution in southern Africa. Here, we analyzed 55 individuals collected from 7 localities in South Africa by G- and C-banding and chromosome painting with flow sorts of Myotomys unisulcatus. Of the 55 specimens that were analyzed, 47% contained inversions or centromeric shifts on 4 autosomes (OIR1, 4, 6 and 10) which were present singly in specimens (i.e. none of the specimens contained all 4 inversions concurrently). These inversions were found in both homozygous and heterozygous state over a wide geographic range suggesting that they are floating polymorphisms. Given the potential role of inversions in post-mating isolation (through production of aneuploid gametes), the prevalence of inversions as floating polymorphisms in the vlei rats suggests that they are probably retained in the population through suppression of recombination in the inverted regions of the chromosomes.

Association of glycaemia with lipids in adults with type 1 diabetes: modification by dyslipidaemia medication

AIMS/HYPOTHESIS

Hyperglycaemia and dyslipidaemia are common metabolic abnormalities in adults with type 1 diabetes and both increase cardiovascular disease (CVD) risk. The hypothesis of this study was that change in HbA(1c) over 6 years would be associated with change in fasting lipids in adults with type 1 diabetes.

METHODS

The Coronary Artery Calcification in Type 1 Diabetes (CACTI) study examined 652 patients with type 1 diabetes (54% female); 559 and 543 had follow-up visits at 3 and 6 years. Baseline age (mean ± SD) was 37 ± 9 years, diabetes duration 23 ± 9 years, and HbA(1c) 8.0 ± 1.3%. Use of dyslipidaemia medication was 17%, 32%, and 46% at the three visits. Separate longitudinal mixed models were fitted to examine the relationship between change in HbA(1c) and change in fasting total cholesterol (TC), HDL-cholesterol (HDL-c), LDL-cholesterol (LDL-c), log triacylglycerols (TG), and non-HDL-cholesterol (non-HDL-c). Because of an interaction between dyslipidaemia medication use and association of HbA(1c) with lipids, results were stratified by dyslipidaemia medication use.

RESULTS

Among patients not using dyslipidaemia medication, a higher HbA(1c) was associated with significantly worse levels of the lipids TC, LDL-c, TG and non-HDL-c (per 1% change in HbA1c, TC 0.101 mmol/l, 95% CI 0.050, 0.152; LDL-c 0.103 mmol/l, 95% CI 0.058, 0.148; TG 0.052 mmol/l, 95% CI 0.024, 0.081; and non-HDL-c 0.129 mmol/l, 95% CI 0.078, 0.180) but not HDL-c (-0.20 mmol/l, 95% CI -0.047, 0.007). The associations between HbA(1c) and any lipid outcome among those on dyslipidaemia medication were in the same direction, but attenuated compared with persons not on medication.

CONCLUSIONS/INTERPRETATION

Change in HbA(1c) is significantly associated with change in fasting lipids, but dyslipidaemia medications may be required to optimise lipid and cardiovascular health.

Complications of obesity in children and adolescents

The increasing prevalence and severity of obesity in children and adolescents has provided greater emphasis on the wide variety of comorbid conditions and complications that can be experienced as a consequence of obesity. These complications can occur both in the short term and in the long term. Some complications, earlier thought to be long-term issues, which would only occur in adulthood, have now been shown to occur in children and adolescents. These findings have raised concerns about the overall health experience of those who develop obesity early in life and have even raised questions about whether the obesity epidemic might shorten the life span of the current generation of children. In this paper, I will examine current knowledge regarding the different organ systems that may be impacted by childhood obesity.

The relationship between meal frequency and body mass index in black and white adolescent girls: more is less

OBJECTIVE

To document meal frequency and its relationship to body mass index (BMI) in a longitudinal sample of black and white girls from ages 9-19 years.

DESIGN

Ten-year longitudinal observational study.

SUBJECTS

At baseline, 1209 Black girls (539 age nine years, 670 age 10 years) and 1,166 White girls (616 age nine years, 550 age 10 years) were enrolled in the National Heart, Lung and Blood Institute Growth and Health Study (NGHS).

MEASUREMENTS

Three-day food diaries, measured height and weight and self-reported physical activity and television viewing were obtained at annual in-person visits.

RESULTS

Over the course of the study, the percentage of girls eating 3+ meals on all 3 days was reduced by over half (15 vs 6%). Participants who ate 3+ meals on more days had lower BMI-for-age z-scores. Black girls, but not white girls, who ate 3+ meals on more days were less likely to meet criteria for overweight.

CONCLUSION

Meal frequency was related to BMI and should be considered when developing guidelines to prevent childhood overweight.

Cardiovascular disease risk factors and atherosclerosis in children and adolescents

As more is learned about the natural history of the development of atherosclerosis, it is clear that the process that results in morbidity and mortality in adults has its origins in childhood and adolescence. It is also clear that the traditional risk factors, such as hypertension and dyslipidemia, are important in the early stages of the process. It appears that the prevalence and severity of obesity are increasing in children and adolescents in the United States. This trend is associated with increasing blood pressure and the occurrence of type 2 diabetes mellitus in young individuals. These trends may result in increased cardiovascular morbidity and mortality as these overweight pediatric patients become obese adults. Intervention and prevention strategies should be directed at the pediatric population as a whole, as well as at higher-risk individuals. For the latter, it will be necessary to identify those at highest risk. Both nonpharmacologic and pharmacologic approaches may be necessary for treatment of pediatric patients with hyperlipidemia and hypertension. Studies are needed that evaluate the longer-term impact of intervention on cardiovascular risk factors in young patients.

Effects of race, cigarette smoking, and use of contraceptive medications on resting energy expenditure in young women

The prevalence of obesity is higher in Black women than in White women (JAMA 1994;272:205-11; Arch Pediatr Adolesc Med 1995;149:1085-91). Although it has been shown that Black women have a lower resting energy expenditure (REE), factors affecting REE remain unclear. This 1996-1997 study in Cincinnati, Ohio, assessed racial differences in REE and their determinants in a biracial cohort of 152 healthy young women aged 18-21 years. Two indirect calorimetric measurements were obtained during two overnight hospital admissions 10-14 days apart. Body composition was measured by using dual-energy x-ray absorptiometry. Mean REE (adjusted for body composition, smoking, and contraceptive medication use) was significantly (p = 0.04) lower by 71 kcal/day in Black women (1,453 (standard error, 21) kcal/day) than in White women (1,524 (standard error, 19) kcal/day). Smoking was associated with a REE that was 68 kcal/day higher for both groups (p = 0.03). A trend (p = 0.07) toward increased REE (by 46 kcal/day) was found with contraceptive medication use. In conclusion, young Black women had a significantly lower REE than did White women. Cigarette smoking significantly increased REE. The apparent presence of a more parsimonious energy metabolism in Black women suggests that maintenance of energy homeostasis requires particular vigilance in this high-risk population.

Changes in left ventricular mass index in children and adolescents after renal transplantation

Recent reports indicate a high prevalence of left ventricular hypertrophy (LVH) in children on dialysis and after renal transplantation (Tx), as identified by cross-sectional analysis. However, the evolution of LVH in pediatric patients with end-stage renal disease after renal Tx is not well established. To assess changes of left ventricular mass (LVM), we prospectively performed echocardiography in 23 children and adolescents between November 1998 and July 2000. Each patient had an echocardiographic evaluation while on dialysis (for at least 6 weeks) and a follow-up evaluation at least 6 months after successful renal Tx (i.e. with a measured glomerular filtration rate [GFR] of at least 40 mL/min/1.73 m2). The LVM index was estimated by indexing LVM to height(2.7). Sixteen patients had a cadaveric transplant and seven had a live donor transplant; the mean duration between the two studies was 1.9 +/- 1.6 yr; and the mean GFR was 55.0 +/- 21.4 mL/min/1.73 m2. There was no significant difference in the mean values of the LVM index while on dialysis and after renal Tx (43.9 +/- 17.8 g/m2.7 and 39.3 +/- 12.0 g/m2.7, respectively, p = 0.19), or in the prevalence of LVH (52% and 56%, respectively). Interval changes in the LVM index in individual subjects between the two studies were significantly associated with interval changes in indexed systolic (r = 0.42, p = 0.04) and diastolic (r = 0.42, p = 0.05) blood pressures. Interval changes in hemoglobin, blood urea nitrogen (BUN), creatinine, and duration after Tx did not correlate with changes in the LVM index. There was no significant difference in LVM index change according to the type of dialysis, donor source, and the cause of renal failure. In multivariate analysis, the baseline LVM index and changes in indexed SBP were independent predictors for LVM index change after renal Tx. We conclude that LVH persists in children and adolescents after renal Tx. Control of blood pressure might be an important factor in regression or prevention of progression of LVH in these patients.

Relation of heart rate to left ventricular dimensions in normotensive, normal-weight children, adolescents and adults

BACKGROUND

The quantitative relation between body growth and changes in heart rate, and the relationship of heart rate to left ventricular (LV) dimensions, independent of the influence of body size, have been only marginally investigated. Accordingly, we designed this study to investigate the relation between heart rate, body size and LV dimensions in children, adolescents and adults over a broad age span.

METHODS

Eight hundred and nineteen normotensive, multi-racial, normal-weight individuals (444 males, 375 females, aged 1-85 years) with normal LV systolic function were studied at echocardiography in three centers, using previously reported methods. The resting heart rate was measured on the M-mode echo-tracing or right after the echocardiogram with the subject still in the supine position.

RESULTS

In children and adolescents (up to 17 years), the heart rate decreased with increasing body height (r = -0.51, p < 0.0001) and body weight (r = -0.42, p < 0.0001), in a similar manner in girls and boys. In adults, the heart rate was higher in women than in men, but it was not independently related to body size. The LV diastolic diameter was higher in males and decreased with increasing heart rate in children and adolescents (r = -0.45) as well as in adults (r = -0.25, both p < 0.0001). This relation was also independent of the effect of body size, sex and race. Similarly, the LV mass increased with decreasing heart rate in children and adolescents (r = -0.45), but the association was not confirmed after controlling for body size, sex and race. In adults, heart rate was inversely related to LV mass (r = -0.21, p < 0.0001), and this relation was also independent of body size, sex, race, age and blood pressure (p < 0.001). In women, the relation of heart rate to LV mass/height2.7 was less close than in men, due to the greater increase in LV mass with age.

CONCLUSIONS

The heart rate has an inverse association with the LV chamber diameter and with the LV mass in children-adolescents and in adults. This relation is largely, but not uniquely, mediated by body proportions, especially during body growth.

Changes in left ventricular mass in children and adolescents during chronic dialysis

Left ventricular hypertrophy (LVH) is an independent risk factor for cardiac mortality in adults with end-stage renal disease (ESRD). It is prevalent in pediatric patients on chronic dialysis. The objectives of this study were to evaluate left ventricular mass (LVM) in children and adolescents at the initiation of dialysis and to assess its changes during chronic dialysis therapy. In this longitudinal analysis, 29 patients aged 4-18 years had an echocardiographic evaluation within 90 days of starting dialysis therapy and a follow-up study at least 6 months later. LVH was defined as LVM index (g/m2.7) > 95th percentile for normal children and adolescents. On the initial echocardiogram 20 of 29 (69%) patients had LVH and 24 patients (83%) had abnormal LV geometry (38% eccentric LVH, 31% concentric LVH, and 14% concentric remodelling). Patients with LVH were more likely to be on antihypertensive medications (16/20) than patients without LVH (3/9) (P = 0.005). Repeat echocardiogram, performed after 10 +/- 3 months on chronic dialysis, showed no significant difference in the mean LVM index (49.6 +/- 17.5 g/m2.7 and 49.7 +/- 16.1 g/m2.7, respectively) or in the prevalence of LVH or LV geometric pattern. However, 14 of 29 patients had a progressive increase in LVM index and 15 patients had regression. Multiple regression analysis showed that baseline LVM index (P = 0.005) and interval change in indexed systolic blood pressure (P = 0.027) were independent predictors for LVM index changes. In summary, LVH and abnormal LV geometry are already prevalent in children and adolescents with renal failure at the time of initiation of dialysis therapy, indicating that LVH develops during the pre-ESRD course. Early intervention to control blood pressure may be an important factor to improve and prevent progression of LVH in pediatric patients with ESRD.

Racial divergence in adiposity during adolescence: The NHLBI Growth and Health Study

BACKGROUND

Black women are particularly vulnerable to obesity, with a prevalence rate of >50%. The higher mortality and morbidity from cardiovascular disease, stroke, and diabetes have been attributed, in part, to their obesity. In recent years, a particular public health concern is the increasing secular trend in obesity with an even greater racial disparity, especially in girls and women. Between the early 1960s and late 1980s, the prevalence of obesity tripled in young black girls 6 to 11 years of age, while it doubled in white girls. Similarly, both overweight and obesity in adolescent girls 12 to 17 years of age also increased, with a greater increase again seen in adolescent black girls. This secular trend in obesity with a greater increase in black girls signals a potentially grave future chronic disease burden on black women, which is already higher than in white women. The increasing occurrence in children and adolescents of noninsulin-dependent diabetes, traditionally viewed as an adult-onset condition, may be a consequence of the currently high prevalence of obesity in American youth. Not surprisingly, this condition is seen more frequently among black youths. Prepubescent black girls are generally leaner than age-comparable white girls, but by 20 years of age, black women are considerably heavier than are white women. Thus, it is assumed that the racial disparity in adiposity evolves during adolescence. However, the specific age at which this occurs and underlying factors are yet to be identified because of the current paucity of longitudinal cohort data.

OBJECTIVES

In 1985, the National Heart, Lung, and Blood Institute (NHLBI) initiated a 10-year longitudinal multicenter study (the NHLBI Growth and Health Study [NGHS]) to investigate the development of obesity in black and white girls during adolescence and its environmental, psychosocial, and cardiovascular disease risk factor correlates. The purpose of this report is to examine the natural history of adiposity and weight accretion during adolescence in a biracial cohort of girls to investigate the evolution of the racial divergence in adiposity and to examine the relationships between increases in adiposity and pubertal maturation, energy intake, and physical activity.

PARTICIPANTS AND SETTING

A total of 2379 black (51%) and white (49%) girls, 9 to 10 years of age, were recruited from public and parochial schools in Richmond, California, and Cincinnati, Ohio, and from families enrolled in a large health maintenance organization in the Washington, DC area. Participant eligibility was limited to girls and their parents who declared themselves as being either black or white and who lived in racially concordant households. DESIGN AND STATISTICAL ANALYSIS: The NGHS is a multicenter prospective study of black and white girls with annual visits from 9 to 10 years of age through 18 to 19 years of age. The follow-up rate was 89% at the 10th annual visit. Skinfold measurements were obtained at the triceps, suprailiac, and subscapular sites with Holtain calipers. Sexual maturation was assessed by trained registered nurses. The onset of menarche was ascertained annually by questionnaire. All clinical assessments were conducted using a common protocol by centrally trained staff. Longitudinal regression (generalized estimating equations) models were used to examine the relationship between adiposity and race, age, pubertal maturation, daily energy intake, and physical activity.

MAIN OUTCOME MEASURES

The main outcome measure was the sum of skinfolds (SSF) at the triceps, subscapular, and suprailiac sites as an index of adiposity for comparison between the 2 racial groups. Body mass index (BMI; weight in kilograms divided by height in meters, squared) distributions were examined by age and race.

RESULTS

Racial differences in SSF, unadjusted for maturation, were evident at 10 years of age. For each chronological age, there was a higher proportion of black girls with more advanced pubertal maturation than white girls. The 15th percentiles for SSF were similar and remained thus throughout the study. The median for SSF for black girls, although similar to the median SSF of white girls at 9 years of age, became greater for black girls at 12 years of age (36 mm vs 32.5 mm) and at age 19 years the difference was 6 mm (49.5 mm vs 43.5 mm). In contrast, the difference in the 85th as well as the 95th percentile values for SSF were substantially higher in black girls at all ages (9 mm and 10 mm, or 18% and 15%, respectively, at age 9 years) and these racial differences widened with age (20 mm and 26 mm, or 25% and 24%, respectively, by age 19 years). The racial difference in the median BMI increased from 0.4 to 2.3 kg/m(2) between ages 9 and 19 years. Unlike SSF at the 15th percentile, the BMI for lean 9-year-old black girls was ~3% higher than whites. (ABSTRACT TRUNCATED)

The prevalence of upper lip hair in black and white girls during puberty: a new standard

In order to develop standards for upper lip hair in adolescent girls, 4693 observations in 856 black and white subjects were made over 9 years. Up to 2 years after menarche, 90% of girls had no upper lip hair. More than 2 years after menarche, 48.8% of black girls and 9.0% of white girls had small amounts of upper lip hair. This may be more significant in adolescent girls than in older women.

Utility of different measures of body fat distribution in children and adolescents

The distribution of body fat has been shown to be an important determinant of cardiovascular disease risk. The purpose of this study was to evaluate which method of evaluating body fat distribution compares most favorably with dual-energy x-ray absorptiometry. The study included 201 children and adolescents aged 7-17 years who were recruited from Cincinnati, Ohio, schools in 1992-1993. The strongest correlate of fat distribution was waist circumference (r = 0.80). Age was a more important determinant of fat distribution than was pubertal maturation. There was a greater relative deposition of central body fat with increasing age. Multiple regression analysis demonstrated that waist circumference was the best simple measure of fat distribution, since it was least affected by gender, race, and overall adiposity. Waist circumference is easy to determine and is a useful measure of fat distribution for children and adolescents.

Severe left ventricular hypertrophy in pediatric dialysis: prevalence and predictors

Left ventricular hypertrophy (LVH) has been recognized as an independent risk factor for cardiovascular morbidity and mortality in adults with end-stage renal disease. However, the prevalence and severity of LVH in children on chronic dialysis therapy is not well established. Retrospectively, 64 chronic dialysis patients, aged 20 months to 22 years, on chronic dialysis had echocardiographic evaluation of LV mass (LVM) and geometry. Forty-eight (75%) children had LVH, including 22 of 26 (85%) on hemodialysis (HD) and 26 of 38 (68%) on peritoneal dialysis (PD). The prevalence of LVH in patients on HD was significantly higher than those on PD (P=0.02). Abnormal LV geometry was found in 51 of 64 (80%) patients: 25 patients (39%) had eccentric hypertrophy, 3 (5%) had concentric remodelling, and 23 (36%) had concentric LVH. Twenty-six children (41%) had severe LVH, defined as LVM index greater than 51 g/m2.7, which is associated with a fourfold greater risk for development of cardiovascular disease in adults. Patients with severe LVH had a significantly lower hemoglobin level (P=0.027) and longer duration of renal disease prior to the start of dialysis therapy (P=0.003) than patients without LVH. Multiple logistic regression analysis revealed HD as opposed to PD as a significant independent predictor for severe LVH (P=0.036). Higher systolic blood pressure remained in the final model as an independent predictor with a borderline level of significance (P=0.065). The results indicate that severe LVH and abnormal left ventricular geometry are common in young dialysis patients. Better control of blood pressure, anemia, and hypervolemia may be important in prevention or improving LVH.

Blood pressure differences between blacks and whites in relation to body size among US children and adolescents

No large national studies of ethnic differences in blood pressure among children accounting for body size differences have been published, to the authors' knowledge. This report details the similarities and differences in systolic and diastolic blood pressures between Black children and White children in the United States and examines the effects of age, sex, and body size on ethnic differences in blood pressure levels. Standardized measurements of seated systolic and diastolic pressures from eight large epidemiologic studies published between 1978 and 1991 that included measurements of 47,196 children on 68,556 occasions for systolic pressure and for 38,184 children on 52,053 occasions for diastolic pressure were used; 51 percent (24,048 children) were boys and 37 percent (17,466 children) were Black. Overall, there appear to be few substantive ethnic differences in either systolic or diastolic pressure during childhood and adolescence. The differences that were observed were small, inconsistent, and often explained by differences in body size. There was an ethnic group-body mass index (BMI) interaction that resulted in these findings that at lower levels of BMI Blacks have higher blood pressure and more hypertension than do Whites, but that at the highest levels of BMI, Whites have more hypertension (systolic or diastolic pressure) than do Blacks.

Relation of left ventricular chamber and midwall function to age in normal children, adolescents and adults

BACKGROUND

The goal of this study was to identify the effect of body growth and aging, and normal limits of the relation of left ventricular endocardial and midwall shortening to wall stress.

METHODS

Endocardial and midwall shortening and circumferential end-systolic stress were assessed in 388 normotensive, normal-weight adults (226 men, 162 women, age 18 to 85 years) and 332 children and adolescents (180 males, 152 females, age 4 to 17 years) by two-dimensional targeted M-mode echocardiography and cuff blood pressure measurements.

RESULTS

End-systolic stress decreased with age in children and adolescents (p < 0.001), but not during adulthood and maturity. The negative relation of endocardial shortening to end-systolic stress was stronger in adults than in children and adolescents (slope difference p < 0.005). The negative relation of midwall shortening to end-systolic stress was negligible in children and adolescents (r = -0.07, p = 0.18), whereas it was more evident, although weak, in adults (r = -0.14, p < 0.007). For a given level of end-systolic stress, endocardial shortening decreased by 0.32%/year in children and adolescents (multiple r = 0.51, p < 0.0001) and by 0.05%/year in adults, whereas midwall shortening decreased by 0.26%/year during body growth and by 0.02%/year in adults.

CONCLUSIONS

In the presence of normal blood pressure and normal weight, the relations between left ventricular wall stress and both chamber and myocardial function are weakly but significantly influenced by age. Left ventricular chamber function is markedly influenced by wall stress, while this influence is reduced for left ventricular wall mechanics.

Pathogenesis of dilated cardiomyopathy: molecular, structural, and population analyses in tropomodulin-overexpressing transgenic mice

Dilated cardiomyopathy is characterized by decreased contractile function and loss of myofibril organization. Previously unexplored structural and molecular events that precede and initiate dilation can now be studied in tropomodulin-overexpressing transgenic (TOT) mice exhibiting progressive dilated cardiomyopathy. Onset of dilation did not correspond to a change in transgene expression levels, which were more than threefold above normal at birth and remained elevated throughout postnatal life. Similarly, mitogen-activated protein kinase activation (p38, ERK1/ERK2, JNK1/JNK2) was not associated with dilation. In contrast, calcineurin was activated before dilation, presumably due to doubling of intracellular diastolic calcium levels in TOT cardiomyocytes. Amplitude of systolic calcium transients was greatly increased as well, demonstrating the novel and unique calcium handling profile of TOT cardiomyocytes. Loss of myofibril organization was not apparent by confocal microscopy until over 1 week after birth, although neonatal sarcomeric abnormalities were revealed by ultrastructural analysis. Rapid postnatal increases in heart:body weight ratio at 1.5 weeks were followed by two waves of mortality between 2 and 3 weeks after birth coincident with maturational stress. Ultimately, TOT pathogenesis is a compensatory response to altered sarcomeric structure driven by calcineurin activation within days after birth, making TOTs an excellent paradigm for studying the role of calcium overload in dilated cardiomyopathy.

Serum glutathione in adolescent males predicts parental coronary heart disease

BACKGROUND

Traditional risk factors account for only half of the morbidity and mortality from coronary heart disease (CHD). There is substantial evidence that oxidative injury plays a major role in the atherosclerotic process. Thus, antioxidants may protect against development of atherosclerosis. Glutathione, an intracellular tripeptide with antioxidant properties, may be protective.

METHODS AND RESULTS

This case-control study compared total serum glutathione (tGSH) in 81 adolescent male offspring of parents with premature CHD (ie, before 56 years of age) and 78 control male offspring of parents without known or suspected CHD. Case offspring had significantly lower tGSH than control offspring. In multiple logistic regression with parental CHD status as the dependent variable, age entered as a covariate, and other CHD risk factors competing to enter the model as significant independent predictor variables, LDL cholesterol (odds ratio [OR], 2.15 [units=1.5 SD]; 95% CI, 1.21 to 3.82), tGSH (OR, 0.40; 95% CI, 0.22 to 0.71), HDL cholesterol (OR, 0.42; 95% CI, 0.22 to 0.78), and total serum homocysteine (OR, 2.6; 95% CI, 1.35 to 5.02) entered the model as significant predictors of parental CHD status.

CONCLUSIONS

Low tGSH in adolescent boys is a significant independent predictor of parental CHD, in addition to elevated LDL cholesterol, low HDL cholesterol, and elevated total serum homocysteine concentrations.

Sex and race differences in cardiovascular disease risk factor changes in schoolchildren, 1975-1990: the Princeton School Study

OBJECTIVES

This study was done to assess changes in obesity and risk factors for cardiovascular disease (CVD) in Black and White children from 1975 through 1990.

METHODS

A cross-sectional study of body composition and CVD risk factors conducted in a school district as part of the Lipid Research Clinics (LRC) Program Prevalence Study (1973-1975) was compared with a later study (1989-1990) conducted in the same school district, which remained demographically stable. The studies included 1456 third- and fifth-grade students and 300 LRC subjects within the same age ranges.

RESULTS

Students in the 1989-1990 study had a significantly higher mean body mass index (BMI), total blood cholesterol concentration, and systolic and diastolic blood pressures and marginally higher resting heart rates than those in the earlier study. The prevalence of obesity increased from 12.5% to 25.3%, and of hypercholesterolemia from 8.0% to 14.8%. Black females had the largest increase in BMI and resting heart rate and the highest prevalence of elevated total cholesterol in the 1989-1990 study.

CONCLUSIONS

The results of this study suggest a secular trend toward increased obesity in children and portend the potential development of a public health problem that could reverse the recent decline in morbidity from CVD.

Overweight, fat patterning, and cardiovascular disease risk factors in black and white boys

PURPOSE

To evaluate the relationships of overweight and fat patterning with cardiovascular disease (CVD) risk factors in black and white boys.

DESIGN

Cross-sectional analysis of CVD risk factors by weight and central adiposity groups in black and white boys, aged 10 to 15 years. Mean adiposity, lipid, and blood pressure variables were compared between weight and central adiposity groups within race by using linear regression models. Observed clustering of risk factors within weight and adiposity groups was compared with the expected clustering under an assumption of no association.

RESULTS

Within each racial group, overweight boys had greater skinfolds, lower high-density lipoprotein cholesterol levels, higher low-density lipoprotein cholesterol and triglyceride levels, and higher systolic and diastolic blood pressure than non-overweight boys. Among overweight boys, greater central adiposity was associated with higher risk factor levels and increased clustering of risk factors.

CONCLUSION

Overweight and central adiposity together profoundly affect CVD risk factor levels and risk factor clustering in black and white boys.

Overweight, fat patterning, and cardiovascular disease risk factors in black and white girls: The National Heart, Lung, and Blood Institute Growth and Health Study

OBJECTIVE

To determine the association of overweight and central adiposity with cardiovascular disease risk factors in black and white 9- and 10-year-old girls.

DESIGN

Cross-sectional analysis of baseline data collected from participants in the National Heart, Lung, and Blood Institute Growth and Health Study. Girls were classified as overweight or not with the use of the age- and sex-specific 85th percentiles of the body mass index (kilograms per square meter) distributions from the combined NHANES (I and II) data set. Mean indexes of central adiposity, blood pressure levels, and lipid concentrations and the clustering of risk factors based on published cut points were compared between weight groups by race and by central adiposity group within weight and race groups.

RESULTS

Overweight was associated with increased risk factor levels and with increased clustering in both black and white girls. Among overweight girls greater central adiposity was associated with higher risk factor levels and increased clustering.

CONCLUSIONS

Given the associations between cardiovascular disease risk factors and both overweight and central adiposity, the secular trends toward increased obesity in American youth portend a worsening of cardiovascular disease risk profiles.

Hypertension-induced cardiac damage in children and adolescents

Blood pressure elevation has numerous sequelae, including myocardial infarction, stroke, congestive heart failure, end-stage renal disease, and peripheral vascular disease in adults. The impact of blood pressure elevation on target organs in children and adolescents has been less well studied. The most useful measure of cardiac effects of hypertension is the echocardiogram. Studies have now defined normal standards for left ventricular mass in young patients. In order to account for differences in body size, it is most appropriate to use left ventricular mass divided by the individual s height raised to a power of 2.7. It has been demonstrated that there is a high prevalence of left ventricular hypertrophy in adolescents with essential hypertension. Some adolescents develop severe hypertrophy and abnormal left ventricular geometry, even to a degree that would be associated with increased risk of cardiovascular disease morbidity in an adult patient. Further research is needed to better evaluate the regression of left ventricular hypertrophy. Clinicians should assess left ventricular mass index in the evaluation of pediatric patients with hypertension.

Association of body fat distribution and cardiovascular risk factors in children and adolescents

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 (P<0.05) univariate correlations between fat distribution and log triglycerides (r=0.27), log HDL cholesterol (r=-0.23), systolic blood pressure (r=0.26), and left ventricular mass (r=0.37). 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. Greater deposition of central fat (an android fat pattern) is associated with less favorable plasma lipid and lipoprotein concentrations, blood pressure, and left ventricular mass.

Prevalence and correlates of blood pressure elevation in children with Guillain-Barré syndrome

While there have been case reports describing blood pressure elevation in adults and children with Guillain-Barré syndrome (GBS), no previous systematic study has explored the prevalence of hypertension in children with this condition. In a retrospective review, blood pressure elevation was seen in 20 of 30 (66.7%) patients with GBS admitted to a children's hospital during a 10-year period. There was a significant correlation between highest GBS stage and deviation of systolic blood pressure from age- and gender-specific norms (r = 0.93, p < 0.05). Since blood pressure may be markedly elevated in GBS, the clinician caring for a child with this condition should be aware of this complication.

Effect of veno-venous ultrafiltration on myocardial performance immediately after cardiac surgery in children. A prospective randomized study

OBJECTIVES

This study sought to evaluate the effects of veno-venous ultrafiltration on myocardial contractility in children undergoing cardiopulmonary bypass (CPB) for repair of congenital heart defects.

BACKGROUND

Ultrafiltration (UF) is currently used to diminish postoperative fluid accumulation following CPB in children. Previous reports indicate improvement in hemodynamics immediately after UF, but the mechanism of its action is unknown.

METHODS

Twenty-three patients (ages 2 months to 9.1 years; 13 males, 10 females) underwent UF for 10 min after CPB. Twelve patients underwent UF immediately after CPB (Group A). They were studied: (1) before and (2) after CPB, (3) after UF, and (4) 10 min after UF. Eleven patients underwent UF 10 min after CPB (Group B). They were studied: (1) before and (2) after CPB, (3) after a 10-min delay before UF, and (4) after UF. Contractility was determined by the difference in the observed and predicted velocity of circumferential fiber shortening for the measured wall stress, using transesophageal echocardiography. Left ventricular wall thickness was also measured.

RESULTS

There was significant improvement in contractility after UF in both groups (mean+/-SD, Group A: -0.28+/-0.13 to -0.01+/-0.21 circ/s, p < 0.05; Group B: -0.26+/-0.16 to -0.11+/-0.17 circ/s, p < 0.05). Myocardial thickness to cavity dimension decreased in both groups following UF (Group A: 0.19+/-0.04 to 0.14+/-0.03, p < 0.05; Group B: 0.18+/-0.04 to 0.14+/-0.03, p < 0.05).

CONCLUSIONS

UF improves hemodynamics by improving contractility and possibly by reducing myocardial edema in children following cardiac surgery. Enhanced patient outcome after ultrafiltration may in part be due to these changes.

Nocturnal blood pressure in young patients with insulin-dependent diabetes mellitus: correlation with cardiac function

Lack of a decline in nocturnal blood pressure is associated with an adverse effect on end organs in adults with insulin-dependent diabetes mellitus (IDDM). The role of the decline in nocturnal blood pressure in young patients with IDDM is not known. We studied 25 white subjects with IDDM (age = 20.8 +/- 3.7 years, mean +/- SD), 8 of whom were female. The duration of IDDM in these subjects was 12.9 +/- 5.4 years (mean +/- SD). We determined the values for glycosylated hemoglobin (HgbA1), 24-hour ambulatory blood pressure, diastolic cardiac function (the ratio of peak E wave to peak A wave velocity (E/A) and indexed peak filling rate ¿PFR/SV¿ by Doppler echocardiography), and albumin excretion rate. The HgbA1 level was 10.9% +/- 1.9% (mean +/- SD; normal range = 4.5%-8.5%). The HgbA1 concentration was inversely correlated (p < 0.005) with the decline in systolic (r = 0.57) and diastolic (r = -0.55) nocturnal blood pressure. Diastolic cardiac dysfunction ¿E/A ratio [r = 0.42, p < 0.03) and PFR/SV (r = 0.52, p < 0.01)¿ correlated with a smaller decrease in nocturnal diastolic blood pressure. An inverse correlation between decline in nocturnal systolic blood pressure and log albumin excretion rate (r = -0.37, p = 0.07) approached statistical significance. We conclude that poor glycemic control adversely affects nocturnal blood pressure and that the latter may play an important role in cardiac and possibly renal dysfunction in early IDDM.