Racial/ethnic discrepancies in the metabolic syndrome begin in childhood and persist after adjustment for environmental factors

Depressive symptoms are associated with worsened severity of the metabolic syndrome in African American women independent of lifestyle factors: A consideration of mechanistic links from the Jackson heart study

BACKGROUND

Depression and the metabolic syndrome (MetS) are both risk factors for cardiovascular disease and type 2 diabetes mellitus. Prior studies in predominantly White populations demonstrated that individuals with depressive symptoms at baseline are more likely to develop future MetS. We tested the hypothesis that depressive symptoms would contribute to a more pronounced increase in MetS severity among African Americans in the Jackson Heart Study (JHS).

METHODS

We used repeated-measures modeling among 1743 JHS participants during Visits 1-3 over 8 years of follow-up to evaluate relations between depressive symptom score (Center for Epidemiologic Survey-Depression (CES-D)) at baseline and a sex- and race/ethnicity-specific MetS severity Z-score at each visit.

RESULTS

20.3% of participants had a CES-D score ≥16, consistent with clinically-relevant depressive symptoms. Higher depressive-symptom scores were associated with higher MetS severity in women but not men (p=0.005 vs. p=0.490). There was no difference by depressive symptom score with rate of change in MetS severity over time. Both depressive-symptom score and MetS severity Z-score were associated with lower levels of physical activity and higher levels of C-reactive protein; however, addition of these to the regression model did not attenuate the association between depressive symptoms and MetS severity.

CONCLUSION

African American women but not men in the JHS exhibit relationships between baseline depressive symptoms and MetS severity over an 8-year period. These data may have implications for targeting of MetS-associated lifestyle changes among individuals with depressive symptoms.

The Prevalence and Pathobiology of Nonalcoholic Fatty Liver Disease in Patients of Different Races or Ethnicities

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common cause of liver disease in the United States. The prevalence varies dramatically when comparing individuals of different races and ethnicities. Rates are highest in Hispanic patient populations compared with non-Hispanic whites and African Americans, despite similar rates of the metabolic syndrome and risk factors. This observation remains poorly characterized; variations in genes that effect lipid metabolism may play a role. This article describes the prevalence of NAFLD in patients of different races or ethnicities, and discusses pathophysiologic mechanisms that may explain why these differences exist.

The association between phthalates and metabolic syndrome: the National Health and Nutrition Examination Survey 2001-2010

BACKGROUND

Higher exposure to certain phthalates is associated with a diabetes and insulin resistance, with sex differences seen. Yet, little is known about the association between phthalates and metabolic syndrome (MetS), particularly with consideration for differences by sex and menopausal status.

METHODS

We analyzed data from 2719 participants in the National Health and Nutrition Examination Survey (NHANES) 2001-2010 aged 20-80 years. Five urinary phthalate metabolites (MEP, MnBP, MiBP, MBzP, and MCPP) and DEHP metabolites were analyzed by the Centers for Disease Control and Prevention and were evaluated as population-specific quartiles. MetS was defined by National Cholesterol Education Program's Adult Treatment Panel III report criteria. Prevalence odds ratios (POR) and 95 % confidence intervals (CI) were calculated using multivariable logistic regression, adjusting for potential confounders and stratifying by sex and menopausal status.

RESULTS

Participants with MetS (32 % of the study population) had higher concentrations for all urinary phthalate metabolites. After full adjustment, higher DEHP metabolite concentrations were associated with an increased odds of MetS in men, but not women (adj. POR for men Q4 versus Q1: 2.20; 95 % CI: 1.32, 3.68 and adj. POR for women Q4 versus Q1: 1.50; 95 % CI: 0.89, 2.52). When evaluating by menopausal status, pre-menopausal women with higher concentrations of MBzP had close to a 4-fold increased odds of MetS compared to pre-menopausal women with the lowest concentrations of MBzP (adj POR: Q4 versus Q1: 3.88; 95 % CI: 1.59, 9.49).

CONCLUSIONS

Higher concentrations of certain phthalate metabolites were associated with an increased odds of MetS. Higher DEHP metabolite concentrations were associated with an increased odds of MetS for men. In women, the strongest association was between higher concentrations of MBzP and MetS, but only among pre-menopausal women.

Trends in Metabolic Syndrome Severity and Lifestyle Factors Among Adolescents

BACKGROUND AND OBJECTIVES

Childhood metabolic syndrome (MetS) is a risk factor for adverse outcomes later in life. Our goal was to identify temporal trends among US adolescents in the severity of MetS, its individual components, and factors related to diet and physical activity.

METHODS

We analyzed 5117 participants aged 12 to 19 from NHANES. We used regression analysis of individual waves of data, 1999 to 2012. MetS severity was calculated using a gender- and race/ethnicity-specific MetS severity z score.

RESULTS

There was a linear trend of decreasing MetS severity in US adolescents from 1999 to 2012 (P = .030). This occurred despite a trend of increasing BMI z score (P = .005); instead, the decrease in MetS severity appeared to be due to trends in increasing high-density lipoprotein (HDL; P < .0001) and decreasing triglyceride (P = .0001) levels. In considering lifestyle factors, there was no change in physical activity over the time period. Regarding dietary patterns, total calorie consumption and carbohydrate consumption were positively associated with triglyceride levels and negatively associated with HDL levels, whereas unsaturated fat consumption exhibited the opposite associations. Consistent with these associations, there was a trend of decreasing total calorie consumption (P < .0001), decreasing carbohydrate consumption (P < .0001), and increasing unsaturated fat consumption (P = .002).

CONCLUSIONS

The healthier trend of declining MetS severity in adolescents appeared to be due to favorable increases in HDL and decreases in fasting triglyceride measurements. These were in turn associated with favorable changes in dietary patterns among US adolescents. Future studies should investigate the causality of dietary differences on changes in MetS severity in adolescents.

Insulin-like growth factor-I and insulin-like growth factor binding protein-1 are related to cardiovascular disease biomarkers in obese adolescents

CONTEXT

Insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 have been linked to cardiovascular disease (CVD) risk and pathophysiology in adults, but there are limited data in youth.

OBJECTIVE

The aim of the study was to examine the relationship between IGF and IGFBP-1 with traditional and non-traditional CVD risk factors including inflammatory markers and body composition in an obese pediatric cohort.

DESIGN

A cross-sectional study.

SETTING

The study was carried out at a university children's hospital.

SUBJECTS

Sixty-one obese non-diabetic adolescents.

OUTCOMES

Fasting IGF-I, IGFBP-1, lipoprotein profiles, high-sensitivity C-reactive protein (hsCRP), and total adiponectin as well as insulin sensitivity measures, blood pressure (BP), and anthropometrics.

RESULTS

IGFBP-1 was negatively associated with insulin sensitivity measures, body mass index (BMI), and diastolic BP in males. IGF-I was negatively associated with hsCRP (r = -0.479, p < 0.0005), and IGFBP-1 was positively associated with adiponectin (r = 0.545, p < 0.0005). The IGF-I/CRP and IGFBP-1/adiponectin associations remained significant when controlling for both BMI and insulin sensitivity index (SI ). Both IGF-I and IGFBP-1 were negatively associated with waist circumference (r = -0.327 and r = -0.275, respectively) and sagittal abdominal diameter (r = -0.333 and r = -0.371, respectively), while IGFBP-1 was negatively associated with fat mass (r = -0.347, p = 0.01) as well as neck circumference and fat-free mass in males. Controlling for BMI z-score and SI , IGFBP-1 remained negatively associated with diastolic blood pressure (r = 0.706, p = 0.001 and neck circumference (r = -0.548, p = 0.15) in males.

CONCLUSIONS

IGF-I and IGFBP-1 associate with CVD risk markers and may add to clinical assessments of cardiometabolic dysfunction in youth.

Assessment of human lymphocyte proliferation associated with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS), a cluster of various metabolic conditions, has become epidemic and causes increased morbidity and mortality.

PURPOSE

The aim of this study was to compare lymphocyte proliferation under two different stimuli, Concanavalin A (ConA) and insulin, in a group of patients with MetS (Group 1) and a healthy group (Group 2).

METHODS

Group 1 consisted of 53 patients who met the diagnostic criteria for MetS. Group 2 consisted of 63 patients without MetS. All individuals were evaluated for lipid profile and glycemia. Lymphocyte extraction and culture were performed for each subject and lymphocyte proliferation was assessed using the Alamar blue technique.

RESULTS

There was no gender difference between both groups, but in terms of age, there was a significant difference. The use of Con A at concentrations of 1 and 5 µg/mL induced a high lymphocyte proliferation in both groups. In contrast, when different concentrations of insulin were added, no significant changes in lymphocyte proliferation were observed. However, the proliferation of lymphocytes was significantly higher in Group 1 compared to Group 2 under insulin stimulus, which did not happen under ConA stimulation. Even after age and gender correction, this difference was maintained.

CONCLUSIONS

The increased lymphocyte proliferative response to insulin in patients with MetS found in this study suggests a role of the lymphocyte response to insulin in the pathophysiology of MetS. This response may be used as an immuno-biological marker for MetS, although further studies to evaluate its clinical usefulness need to be conducted.

Severity of the metabolic syndrome as a predictor of type 2 diabetes between childhood and adulthood: the Princeton Lipid Research Cohort Study

AIMS/HYPOTHESIS

The aim of this study was to determine the long-term associations of a sex- and race/ethnicity-specific metabolic syndrome (MetS) severity z score from childhood and adulthood with a future diagnosis of type 2 diabetes mellitus.

METHODS

We performed a prospective cohort study with evaluations from the Cincinnati Clinic of the National Heart Lung and Blood Institute Lipids Research Clinic (LRC) 1973-1976 and Princeton Follow-up Study (PFS) 1998-2003, and further disease status from the Princeton Health Update (PHU) 2010-2014. We assessed MetS severity as a predictor of incident type 2 diabetes among 629 cohort participants assessed at both the LRC and PFS and 354 participants at the PHU.

RESULTS

Cohort participants had a mean age of 12.9 years at baseline (LRC), 38.4 years at the PFS and 49.6 years at the most recent follow-up. Childhood MetS z scores were associated with adult MetS z scores (p < 0.01). Compared with individuals who were disease-free at all time-points, those who developed type 2 diabetes by 1998-2003 and 2010-2014 had higher MetS severity z scores in childhood (p < 0.05). For every one-unit elevation in childhood MetS z score, the OR of developing future type 2 diabetes was 2.7 for incident disease by a mean age of 38.5 years (p < 0.01) and 2.8 for incident disease by a mean age of 49.6 years (p < 0.05). Regarding associations with the change in z score from childhood to adulthood, for every one-unit increase in MetS z score over time the OR of developing incident type 2 diabetes by a mean age of 49.6 years was 7.3 (p < 0.01).

CONCLUSIONS/INTERPRETATION

The severity of MetS in childhood was associated with the incidence of adult type 2 diabetes and the degree of increase in this severity predicted future disease. These findings provide evidence of potential clinical utility in assessing MetS severity to detect risk and follow clinical progress over time.

The severity of the metabolic syndrome increases over time within individuals, independent of baseline metabolic syndrome status and medication use: The Atherosclerosis Risk in Communities Study

BACKGROUND AND AIMS

The severity of the metabolic syndrome (MetS) is linked to future cardiovascular disease. However, it is unclear whether MetS severity increases among individuals followed over time.

METHODS

We assessed changes in a sex- and race/ethnicity-specific MetS severity Z-score over a 10-year period (visits 1-4) among 9291 participants of the Atherosclerosis Risk in Communities study cohort. We compared sex- and racial/ethnic subgroups for the rate of change in the MetS severity score and MetS prevalence as assessed using traditional ATP-III MetS criteria. We further examined effects of use of medications for hypertension, diabetes and dyslipidemia.

RESULTS

Over the 10 years of follow-up, MetS severity Z-scores increased in 76% of participants from an overall mean of 0.08 ± 0.77 at baseline to 0.48 ± 0.96 at visit 4 with the greatest progression in scores observed among African-American women. Baseline MetS severity scores predicted the time until ATP-III MetS diagnosis, with a model-predicted 77.5% of individuals with a visit 1 MetS severity score of 0.75 progressing to ATP-III MetS within 10 years. The rate of increase in MetS severity score was higher among those younger at baseline but was independent of baseline MetS status or the use of medications to treat blood pressure, lipids and diabetes.

CONCLUSION

The severity of metabolic derangements as measured using this MetS severity score increases over time within individuals and predicts diagnosis of ATP-III MetS. These data may have implications for tracking MetS related risk within individuals over time.

Metabolic syndrome is common and persistent in youth-onset type 2 diabetes: Results from the TODAY clinical trial

OBJECTIVE

To examine the prevalence of metabolic syndrome (MetS) in youth-onset type 2 diabetes in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study.

METHODS

Prevalence of MetS (ATP III definition) was compared at baseline (n = 679) and at 6 (n = 625) and 24 months (n = 545) using chi-square tests. Laboratory data were examined between MetS classifications at each time point using ANOVA.

RESULTS

Baseline prevalence of MetS was 75.8% and did not differ by treatment group or change over time. MetS was more common in females (83.1%) than males (62.3%; P < 0.0001) at baseline; this difference persisted over 24 months. Prevalence of MetS was similar between ethnic groups at baseline but greater in Hispanics (82.7%) vs. non-Hispanic Whites (67.5%; P = 0.0017) and non-Hispanic Blacks (72.7%; P = 0.0164) at 24 months. Although MetS was common in participants with hemoglobin A1c < 7.0% (74.4% at baseline; no significant change over 24 months), it was more common in those who did not maintain glycemic control at 6 months (80.3%; P = 0.0081). Elevated C-reactive protein, ALT, IL-6, and PAI-1 levels were more frequent with MetS.

CONCLUSIONS

Persistent high prevalence of MetS in youth-onset diabetes, even with excellent glycemic control, is of concern given the associated increased cardiovascular risk.

Early origins of ethnic disparities in cardiovascular risk factors

BACKGROUND

Not much is known about the ethnic differences in cardiovascular risk factors during childhood in European countries. We examined the ethnic differences in childhood cardiovascular risk factors in the Netherlands.

METHODS

In a multi-ethnic population-based prospective cohort study, we measured blood pressure, left ventricular mass, and levels of cholesterol, triglyceride and insulin at the median age of 6.2years.

RESULTS

As compared to Dutch children, Cape Verdean and Turkish children had a higher blood pressure, whereas Cape Verdean, Surinamese-Creole and Turkish children had higher total-cholesterol levels (p-values<0.05). Turkish children had higher triglyceride levels, but lower insulin levels than Dutch children (p-values<0.05). As compared to Dutch children, only Turkish children had an increased risk of clustering of cardiovascular risk factors (odds ratio: 2.45 (95% confidence interval 1.18, 3.37)). Parental pre-pregnancy factors explained up to 50% of the ethnic differences in childhood risk factors. In addition to these factors, pregnancy and childhood factors and childhood BMI explained up to 50%, 12.5% and 61.1%, respectively.

CONCLUSIONS

Our results suggest that compared to Dutch children, Cape Verdean, Surinamese-Creole and Turkish children have an adverse cardiovascular profile. These differences are largely explained by parental pre-pregnancy factors, pregnancy factors and childhood BMI.

The impact of ethnicity and cardiovascular risk on the pharmacologic management of osteoarthritis: a US perspective

Many individuals with osteoarthritis (OA) also have other chronic, comorbid conditions, such as obesity, hypertension and diabetes, which can compound the risk for developing cardiovascular adverse events that have been associated with specific analgesics, most notably nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase-2 inhibitor NSAIDs. Pharmacotherapy may be further complicated by genetic factors that may influence drug metabolism in certain individuals. These risks may vary according to race and ethnicity. Black and Hispanic populations are known to have a higher prevalence of cardiovascular risk factors and disease, and a substantial proportion of black and Hispanic individuals possess genotypes of the cytochrome P450 (CYP) 2C9 enzyme involved in the metabolism of many NSAIDs and the CYP2D6 enzyme involved in metabolism of the dual opioid agonist/norepinephrine-serotonin reuptake inhibitor tramadol. As a result, the efficacy and safety of available analgesics may vary between patients in different racial and ethnic groups. This review article focuses on racial and ethnic differences in cardiovascular risk and genetic factors altering drug efficacy and safety and evaluates the pharmacologic options that can be used for the management of OA in these populations. Particular emphasis is given to the place of topical NSAIDs and capsaicin in the management of OA patients for whom systemic exposure to available pharmacotherapy poses particular risk. Evidence-based guidelines in OA management, as they relate to appropriate patient-specific pharmacotherapy, are also examined.

Association of serum lead and mercury level with cardiometabolic risk factors and liver enzymes in a nationally representative sample of adolescents: the CASPIAN-III study

This study aims to determine the difference of serum Pb and Hg levels in adolescents with or without metabolic syndrome (MetS) and the association of serum levels of these heavy metals with cardiometabolic risk factors and liver enzymes in Iranian adolescents. The study population consisted of 320 adolescents (160 with MetS and 160 healthy controls). The relationship between serum heavy metals and cardiometabolic risk factors was assessed by linear regression. The odds ratios (OR) of having metabolic syndrome across Pb and Hg quartiles were determined by multiple logistic regression analysis. The mean (SD) of Pb and Hg concentrations were higher in adolescents with MetS than in those without it (0.83 (0.27) and 0.17 (0.01) vs. 0.65 (0.15) and 0.10 (0.08) μg/L, P = 0.01 and 0.0001, respectively). Increase in serum Pb and Hg was associated with increase in some cardiometabolic risk factors. Among boys and girls, diastolic blood pressure (DBP), fasting blood glucose, total cholesterol (TC), triglycerides (TG), and alanine aminotransaminase increased significantly across quartiles of serum Pb. Among girls, SBP, DBP, TC, and TG had a significant increase across Hg quartiles. The corresponding figure among boys was significant for SBP, DBP, and TG. Higher quartiles of Pb increased the risk of having MetS (OR 95 % CI 3.10, 2.25-4.27), the corresponding figure was 2.03, 1.75-3.16, across Hg quartiles. Our study showed significant associations between serum Pb and Hg levels with cardiometabolic risk factors in adolescents. In future surveys, the role of potential confounders should be considered more extensively. The clinical significance of these findings needs to be confirmed in longitudinal studies. By considering the origins of chronic diseases from early life, controlling environmental pollutants should be considered as a health priority for primordial or primary prevention of noncommunicable diseases.

Ethnicity and cardiovascular risk factors: evaluation of 40,921 normal-weight, overweight or obese children and adolescents living in Central Europe

BACKGROUND AND AIMS

Cardiovascular disease (CVD) is a major global health problem and the leading cause of death in Europe. Risk factors such as obesity and hypertension that accelerate the development of CVD begin in childhood. Ethnicity is a known risk factor for CVD in adults. The aim of this study is to explore differences in the prevalence of hypertension and dyslipidemia among overweight/obese and normal-weight children/adolescents of three different ethnic origins living in Central Europe.

METHODS AND PROCEDURES

Prevalence of hypertension and dyslipidemia was calculated among obese/overweight children/adolescents (n = 25,986; mean age 12.7 ± 3.0 years; range: 0-18 years; 46% males) documented in the German-Austrian-Swiss APV (Prospective Documentation of Overweight Children and Adolescents) registry and among normal-weight subjects (n = 14,935; mean age: 8.8 ± 5.1 years; range 0-18 years; 51% males) from the population-based cross-sectional German Health Interview and Examination Survey for Children and Adolescents (KiGGS) study. In both cohorts, subjects were categorized into three ethnic groups (Central European: Germany, Austria, Switzerland; Southeastern European: Turkish; Southern European: Spain, Portugal, Italy, Greece, Cyprus, Malta) based on the country of birth of both parents. Regression models were used to examine ethnic differences after adjustment for age and gender and body mass index (BMI) category.

RESULTS

Age-, gender- and BMI category-adjusted prevalence of hypertension were 38% and 39% for the ethnic minority groups, compared with 35% among German/Austrian/Swiss counterparts. Turkish ethnicity was significantly associated with hypertension (odds ratio (OR) 1.14; 95% confidence interval: 1.02-1.27; P = 0.0446). No significant ethnic differences were found in lipid levels. Prevalence of hypertension found among normal-weight subjects (Central European vs Southeastern vs Southern European: 6.8% vs 6.3% vs 7.2%) did not differ significantly.

CONCLUSIONS

Turkish obese/overweight children/adolescents showed a significantly higher prevalence of hypertension relative to their peers of Central European descent. No significant ethnic difference in the prevalence of hypertension was found among normal-weight children/adolescents. The high prevalence of hypertension among Turkish obese/overweight children/adolescents indicates the need for greater preventive and therapeutic efforts to reduce cardiovascular risk factors among vulnerable populations.

Parental education level is associated with clustering of metabolic risk factors in adolescents independently of cardiorespiratory fitness, adherence to the Mediterranean diet, or pubertal stage

Few studies have reported associations between clustering metabolic risk factors and socioeconomic status (SES) in youth. This study aimed to analyze the association between clustering metabolic risk factors and SES in adolescents. It was hypothesized that SES is inversely related to clustering metabolic risk factors. This 2009 cross-sectional school-based study investigated 517 Portuguese adolescents ages 15-18 years. The study considered the age- and sex-adjusted z-scores for the ratio of total cholesterol/high-density lipoprotein, homeostasis model, triglycerides, and systolic blood pressure, and a metabolic risk score was constructed by summing all the z-scores (≥1 standard deviation was considered high risk). Cardiorespiratory fitness was estimated by the 20 m shuttle-run test and dietary intake by a food frequency questionnaire. The best of parental education was used as a proxy measure of SES. The results showed that adolescents with low SES were more likely to have a high metabolic risk score (odds ratio [OR], 1.96; p < 0.020) regardless of cardiorespiratory fitness, adherence to the Mediterranean diet, or pubertal stage. In conclusion, a lower SES was associated with increased risk for a high metabolic risk score among Azorean adolescents after adjustment for pubertal stage, adherence to the Mediterranean diet, and cardiorespiratory fitness. Future health-promotion strategies among Azorean adolescents should consider the impact of SES on their health.

Síndrome metabólica e associação com nível socioeconômico em escolares

Objetivo verificar a associação entre o nível socioeconômico e a presença de síndrome metabólica (SM) em escolares da rede pública da cidade de Montes Claros-MG. Métodos trata-se de estudo transversal, analítico. Foram avaliados 382 escolares entre 10 e 16 anos, a partir da amostragem por conglomerados. A condição socioeconômica foi dividida em alta e baixa e a SM foi diagnosticada utilizando os critérios da International Diabetes Federation. Para análise dos dados, utilizou-se o teste qui-quadrado (p < 0,05)e oddsratio (com intervalo de 95% de confiança). Resultados os escolares da classe socioeconômica baixa apresentaram alterações no estado nutricional e nos exames laboratoriais, o que contribuiu para presença da SM em 8,7% escolares. Conclusão a condição socioeconômica baixa contribui de forma significante para o diagnótico da SM e atua também na incidência dessa patologia, devido os seus pertencentes estarem mais expostos aos fatores de risco.

Central body fat changes in men affected by post-surgical hypogonadotropic hypogonadism undergoing testosterone replacement therapy are modulated by androgen receptor CAG polymorphism

BACKGROUND AND AIMS

Little is known about the effect of androgen receptor (AR) gene CAG repeat polymorphism in conditioning body composition changes after testosterone replacement therapy (TRT). In this study, we aimed to clarify this aspect by focussing our attention on male post-surgical hypogonadotropic hypogonadism, a condition often associated with partial or total hypopituitarism.

METHODS AND RESULTS

Fourteen men affected by post-surgical hypogonadotropic hypogonadism and undergoing several replacement hormone therapies were evaluated before and after TRT. Dual-energy X-ray absorptiometry (DEXA)-derived body composition measurements, pituitary-dependent hormones and AR gene CAG repeat polymorphism were considered. While testosterone and insulin-like growth factor-1 (IGF-1) levels increased after TRT, cortisol concentration decreased. No anthropometric or body composition parameters varied significantly, except for abdominal fat decrease. The number of CAG triplets was positively and significantly correlated with this abdominal fat decrease, while the opposite occurred between the latter and Δ-testosterone. No correlation of IGF-1 or cortisol variation (Δ-) with Δ-abdominal fat was found. At multiple linear regression, after correction for Δ-testosterone, the positive association between CAG triplet number and abdominal fat change was confirmed.

CONCLUSIONS

In male post-surgical hypogonadotropic hypogonadism, shorter length of AR CAG repeat tract is independently associated with a more marked decrease of abdominal fat after TRT.

Race and the insulin resistance syndrome

Type 2 diabetes remains an important cause of morbidity and mortality. The metabolic syndrome affects 25% of the adult US population based on the Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults from the National Cholesterol Education Program. Knowledge on the impact of obesity on metabolic health parameters has increased greatly over the past decade. This review discusses the limitations of the National Cholesterol Education Program metabolic syndrome definition and the racial disparities in the clinical presentation of the insulin resistance syndrome. We also examine the current literature with particular emphasis on albuminuria, nonalcoholic fatty liver disease, and intramyocellular lipid content. This review explores potential environmental and genetic reasons for differences in the manifestation of insulin resistance across racial/ethnic groups and highlights several promising areas for further study.

Racial/ethnic and immigrant differences in early childhood diet quality

OBJECTIVE

To assess racial/ethnic differences in the diet in young children and the explanatory role of maternal BMI, immigrant status and perception of child's weight.

DESIGN

Among white, black and Hispanic 3-year-olds, we used negative binomial and linear regression to examine associations of race/ethnicity with foods and nutrients assessed by a validated FFQ.

SETTING

Project Viva, Boston (MA), USA.

SUBJECTS

Children aged 3 years (n 898).

RESULTS

Mean age was 38·3 (sd 2·8) months; 464 (52 %) were boys and 127 mothers (14 %) were immigrants. After adjustment for sociodemographic factors, black and Hispanic children (v. white) had a higher intake of sugar-sweetened beverages (rate ratio (RR) = 2·59 (95 % CI 1·95, 3·48) and RR = 1·59 (95 % CI 1·07, 2·47), respectively) and lower intakes of skimmed/1 % milk (RR = 0·42 (95 % CI 0·33, 0·53) and RR = 0·43 (95 % CI 0·31, 0·61), respectively) and trans-fat (-0·10 (95 % CI -0·18, -0·03) % of energy and -0·15 (95 % CI -0·26, -0·04) % of energy, respectively). Among Hispanics only, a lower intake of snack food (RR = 0·83 (95 % CI 0·72, 0·98)) was found and among blacks only, a higher intake of fast food (RR = 1·28 (95 % CI 1·05, 1·55)) and lower intakes of saturated fat (-0·86 (95 % CI -1·48, -0·23) % of energy), dietary fibre (0·85 (95 % CI 0·08, 1·62) g/d) and Ca (-120 (95 % CI -175, -65) mg/d) were found. Being born outside the USA was associated with more healthful nutrient intakes and less fast food.

CONCLUSIONS

Three-year-old black and Hispanic (v. white) children ate more sugar-sweetened beverages and less low-fat dairy. Total energy intake was substantially higher in Hispanic children. Snack food (Hispanic children) and fat intakes (black children) tended to be lower. Children of immigrants ate less fast food and bad fats and more fibre.

Use of CHAID decision trees to formulate pathways for the early detection of metabolic syndrome in young adults

Metabolic syndrome (MetS) in young adults (age 20–39) is often undiagnosed. A simple screening tool using a surrogate measure might be invaluable in the early detection of MetS. Methods. A chi-squared automatic interaction detection (CHAID) decision tree analysis with waist circumference user-specified as the first level was used to detect MetS in young adults using data from the National Health and Nutrition Examination Survey (NHANES) 2009-2010 Cohort as a representative sample of the United States population (n = 745). Results. Twenty percent of the sample met the National Cholesterol Education Program Adult Treatment Panel III (NCEP) classification criteria for MetS. The user-specified CHAID model was compared to both CHAID model with no user-specified first level and logistic regression based model. This analysis identified waist circumference as a strong predictor in the MetS diagnosis. The accuracy of the final model with waist circumference user-specified as the first level was 92.3% with its ability to detect MetS at 71.8% which outperformed comparison models. Conclusions. Preliminary findings suggest that young adults at risk for MetS could be identified for further followup based on their waist circumference. Decision tree methods show promise for the development of a preliminary detection algorithm for MetS.

Diagnostic performance of BMI percentiles to identify adolescents with metabolic syndrome

OBJECTIVES

To compare the diagnostic performance of the Centers for Disease Control and Prevention (CDC) and FITNESSGRAM (FGram) BMI standards for quantifying metabolic risk in youth.

METHODS

Adolescents in the NHANES (n = 3385) were measured for anthropometric variables and metabolic risk factors. BMI percentiles were calculated, and youth were categorized by weight status (using CDC and FGram thresholds). Participants were also categorized by presence or absence of metabolic syndrome. The CDC and FGram standards were compared by prevalence of metabolic abnormalities, various diagnostic criteria, and odds of metabolic syndrome. Receiver operating characteristic curves were also created to identify optimal BMI percentiles to detect metabolic syndrome.

RESULTS

The prevalence of metabolic syndrome in obese youth was 19% to 35%, compared with <2% in the normal-weight groups. The odds of metabolic syndrome for obese boys and girls were 46 to 67 and 19 to 22 times greater, respectively, than for normal-weight youth. The receiver operating characteristic analyses identified optimal thresholds similar to the CDC standards for boys and the FGram standards for girls. Overall, BMI thresholds were more strongly associated with metabolic syndrome in boys than in girls.

CONCLUSIONS

Both the CDC and FGram standards are predictive of metabolic syndrome. The diagnostic utility of the CDC thresholds outperformed the FGram values for boys, whereas FGram standards were slightly better thresholds for girls. The use of a common set of thresholds for school and clinical applications would provide advantages for public health and clinical research and practice.

An examination of sex and racial/ethnic differences in the metabolic syndrome among adults: a confirmatory factor analysis and a resulting continuous severity score

OBJECTIVE

The metabolic syndrome (MetS) is typically diagnosed based on abnormalities in specific clustered clinical measures that are associated with increased risk for coronary heart disease (CHD) and Type 2 diabetes mellitus (T2DM). However, current MetS criteria result in racial/ethnic discrepancies. Our goals were to use confirmatory factor analysis (CFA) to delineate differential contributions to MetS by sub-group, and if contributions were discovered, develop sex and racial/ethnic-specific equations to calculate MetS severity.

RESEARCH DESIGN AND METHODS

Using data on adults from the National Health and Nutrition Examination Survey 1999-2010, we performed a CFA of a single MetS factor that allowed differential loadings across groups, resulting in a sex and race/ethnicity-specific continuous MetS severity score.

RESULTS

Loadings to the single MetS factor differed by sub-group for each MetS component (p<0.001), with lower factor loadings among non-Hispanic-blacks for triglycerides and among Hispanics for waist circumference. Systolic blood pressure exhibited low factor loadings among all groups. MetS severity scores were correlated with biomarkers of future disease (high-sensitivity C-reactive-protein, uric acid, insulin resistance). Non-Hispanic-black-males with diabetics had a low prevalence of MetS but high MetS severity scores that were not significantly different from other racial/ethnic groups.

CONCLUSIONS

This analysis among adults uniquely demonstrated differences between sexes and racial/ethnic groups regarding contributions of traditional MetS components to an assumed single factor. The resulting equations provide a clinically-accessible and interpretable continuous measure of MetS for potential use in identifying adults at higher risk for MetS-related diseases and following changes within individuals over time. These equations hold potential to be a powerful new outcome for use in MetS-focused research and interventions.

Racial Differences in Blood Lipids Lead to Underestimation of Cardiovascular Risk in Black Women in a Nested observational Study

Background:

During screening for enrollment in a clinical trial, we noticed potential racial disparities in metabolic syndrome variables in women who responded to our study advertisement. We designed a nested observational study to investigate whether metabolic syndrome variables differed between non-Hispanic blacks and non-Hispanic whites.

Methods:

The cohort comprised of women who have met the preliminary clinical trial criteria (body mass index [BMI] 25-45, age 20-75 years, and no use of lipid-lowering medications or supplements). These women, including 116 blacks and 138 whites, provided fasting blood samples for analysis of serum lipid profile.

Results:

Blacks had lower mean triglycerides (81.1 ± 3.3 mg/dL vs 140.6 ± 5.9 mg/dL; P < .0001), total cholesterol (176.1 ± 3.6 mg/dL vs 201.6 ± 3.3 mg/dL; P < .0001), and low-density lipoprotein (111.7 ± 3.3 mg/dL vs 128.2 ± 2.9 mg/dL; P < .001) and higher mean BMI (37.2 ± 0.5 vs 35.2 ± 0.5; P < .01) and diastolic blood pressure (82.4 ± 0.8 mmHg vs 79.4 ± 0.7 mmHg; P < .01) than whites. Only 7% of blacks, compared with 41% of whites, had triglycerides ≥150 mg/dL; as a result, fewer black women met metabolic syndrome criteria than white women. Additionally, in women with waist circumference ≥88 cm (N = 215), high-density lipoprotein was higher in blacks than in whites (48.3 ± 1.5 mg/dL vs 44.2 ±1.3 mg/dL; P < .05).

Conclusions:

Due to racial differences in blood lipids, current metabolic syndrome criteria may result in underestimation of cardiovascular risk in blacks.

Interethnic Variation in Lipid Profiles: Implications for Underidentification of African-Americans at risk for Metabolic Disorders

Interethnic differences exist in the distribution of serum lipids, with African Americans (AA) generally having a healthier lipid profile than other US ethnic groups. Similar lipid distributions are observed among other African ancestry groups with distinct lifestyle characteristics, suggesting the importance of inherited factors. Despite healthier serum lipids, AA experience a disproportionate burden of Type 2 Diabetes and Cardiovascular Disease. As evidence of a different relationship between serum lipids and disease exists, the characterization of metabolic risk using lipid concentration (as in Metabolic Syndrome criteria) may lead to the under-identification of AA at risk. Given the disproportionately high rate of metabolic disorders in AA, understanding interethnic differences in the association between serum lipids and disease should be a research priority, as better appreciation of these differences will enhance knowledge of disease etiology, improve intervention targeting, and may lead to mechanisms to ameliorate debilitating health disparities in the US and globally.

Ethnic differences in the link between insulin resistance and elevated ALT

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) exhibits tight links with insulin resistance (IR) and the metabolic syndrome (MetS), a cluster of cardiovascular risk factors. Compared with non-Hispanic whites, non-Hispanic black adolescents have more IR but a lower prevalence of NAFLD and MetS. Our hypothesis was that IR would be a better predictor of alanine aminotransferase (ALT) elevations than is MetS among non-Hispanic blacks.

METHODS

We analyzed data from 4124 adolescents aged 12 to 19 years in the 1999 to 2010 NHANES, using unexplained elevations in ALT (>30 U/L) to characterize presumed NAFLD and using a pediatric adaptation of the Adult Treatment Panel III definition of MetS.

RESULTS

Prevalence of elevated ALT varied by race/ethnicity (Hispanics 13.7%, non-Hispanic white 8.6%, non-Hispanic blacks 5.4%, P < .0001). Among non-Hispanic whites and Hispanics, a classification of MetS performed well in identifying adolescents with elevated ALT (odds ratios [ORs] 9.53 and 5.56, respectively), as did MetS-related indices. However, among non-Hispanic blacks, the association between MetS and ALT elevations was smaller in magnitude and technically nonsignificant (OR = 3.24, P = .051). Furthermore, among non-Hispanic blacks, the presence of IR and elevated waist circumference performed more poorly at identifying ALT elevations (ORs 3.93 and 2.28, respectively: significantly smaller than ORs for non-Hispanic whites, P < .05), with triglyceride elevations being a better predictor (OR = 4.44).

CONCLUSIONS

Non-Hispanic black adolescents exhibit a lower relationship between IR and elevated ALT, supporting racial/ethnic differences in the link between MetS and NAFLD. These data may have implications regarding triggers for screening for NAFLD among non-Hispanic black adolescents, focusing particularly on those with triglyceride elevations.

Lipid and inflammatory cardiovascular risk worsens over 3 years in youth with type 2 diabetes: the TODAY clinical trial

OBJECTIVE

Type 2 diabetes increases cardiovascular risk. We examined lipid profiles and inflammatory markers in 699 youth with recent-onset type 2 diabetes in the TODAY clinical trial and compared changes across treatment groups: metformin alone (M), metformin plus rosiglitazone (M+R), and metformin plus intensive lifestyle program (M+L).

RESEARCH DESIGN AND METHODS

Multiethnic youth with type 2 diabetes received M, M+R, or M+L. Statin drugs were begun for LDL cholesterol (LDL) ≥ 130 mg/dL or triglycerides ≥ 300 mg/dL. Lipids, apolipoprotein B (apoB), LDL particle size, high-sensitivity c-reactive protein (hsCRP), homocysteine, plasminogen activator inhibitor-1 (PAI-1), and HbA1c were measured over 36 months or until loss of glycemic control.

RESULTS

LDL, apoB, triglycerides, and non-HDL cholesterol (HDL) rose over 12 months and then stabilized over the next 24 months. Participants with LDL ≥ 130 mg/dL or using LDL-lowering therapy increased from 4.5 to 10.7% over 36 months, while 55.9% remained at LDL goal (<100 mg/dL) over that time. Treatment group did not impact LDL, apoB, or non-HDL. Small dense LDL (particle size, ≤ 0.263 relative flotation rate) was most common in M. Triglycerides were lower in M+L than M, and M+L attenuated the negative effect of hyperglycemia on triglycerides and HDL in females. hsCRP, PAI-1, and homocysteine increased over time. However, hsCRP was lower in M+R compared with M or M+L.

CONCLUSIONS

Dyslipidemia and chronic inflammation were common in youth with type 2 diabetes and worsened over time. Diabetes treatment, despite some treatment group differences in lipid and inflammatory marker change over time, is generally inadequate to control this worsening risk.

Sex hormone-binding globulin and the risk for metabolic syndrome in children of South Asian Indian origin

OBJECTIVE

To determine whether the plasma level of sex hormone-binding globulin (SHBG) identifies South Asian Indian children at risk for metabolic syndrome.

METHODS

Adults and their children aged 5 to 9 years were recruited at the annual health fair at the Hindu temple serving the South Asian Indian community in Louisville, Kentucky. Anthropometric data were collected in adults and children, and blood pressure, lipid, and glucose levels were measured in adults. SHBG levels were measured in children using a fingerstick blood sample. In adults, metabolic syndrome was diagnosed according to the International Diabetes Federation criteria. Twelve months later, follow-up anthropometric data were obtained for a portion of the children.

RESULTS

The study included 30 sets of parents and 30 children. The prevalence of metabolic syndrome among 310 adults attending the health fair was 42% in men and 39% in women. Children with 1 parent with metabolic syndrome had 24% lower SHBG levels that increased to 55% if both parents had metabolic syndrome. SHBG levels were inversely related to waist circumference and to body mass index percentile. Both SHBG and waist circumference predicted weight gain over 1 year in children. CONCLUSIONS Low SHBG levels were found in South Asian Indian children whose parents had attributes of metabolic syndrome. The dose dependency of SHBG is consistent with inheritance of a genetic trait, and if the results are applicable to other racial/ethnic groups, SHBG may be a useful marker to identify at-risk children for early intervention.

Metabolic syndrome risk profiles among African American adolescents: national health and nutrition examination survey, 2003-2010

OBJECTIVE

Although African American adolescents have the highest prevalence of obesity, they have the lowest prevalence of metabolic syndrome across all definitions used in previous research. To address this paradox, we sought to develop a model of the metabolic syndrome specific to African American adolescents.

RESEARCH DESIGN AND METHODS

Data from the National Health and Nutrition Examination Survey (2003-2010) of 822 nonpregnant, nondiabetic, African American adolescents (45% girls; aged 12 to 17 years) who underwent physical examinations and fasted at least 8 h were analyzed. We conducted a confirmatory factor analysis to model metabolic syndrome and then used latent profile analysis to identify metabolic syndrome risk groups among African American adolescents. We compared the risk groups on probability of prediabetes.

RESULTS

The best-fitting metabolic syndrome model consisted of waist circumference, fasting insulin, HDL, and systolic blood pressure. We identified three metabolic syndrome risk groups: low, moderate, and high risk (19% boys; 16% girls). Thirty-five percent of both boys and girls in the high-risk groups had prediabetes, a significantly higher prevalence compared with boys and girls in the low-risk groups. Among adolescents with BMI higher than the 85th percentile, 48 and 36% of boys and girls, respectively, were in the high-risk group.

CONCLUSIONS

Our findings provide a plausible model of the metabolic syndrome specific to African American adolescents. Based on this model, approximately 19 and 16% of African American boys and girls, respectively, are at high risk for having the metabolic syndrome.

A confirmatory factor analysis of the metabolic syndrome in adolescents: an examination of sex and racial/ethnic differences

Objective

The metabolic syndrome (MetS) is a cluster of clinical indices that signals increased risk for cardiovascular disease and Type 2 diabetes. The diagnosis of MetS is typically based on cut-off points for various components, e.g. waist circumference and blood pressure. Because current MetS criteria result in racial/ethnic discrepancies, our goal was to use confirmatory factor analysis to delineate differential contributions to MetS by sub-group.

Research Design and Methods

Using 1999–2010 data from the National Health and Nutrition Examination Survey (NHANES), we performed a confirmatory factor analysis of a single MetS factor that allowed differential loadings across sex and race/ethnicity, resulting in a continuous MetS risk score that is sex and race/ethnicity-specific.

Results

Loadings to the MetS score differed by racial/ethnic and gender subgroup with respect to triglycerides and HDL-cholesterol. ROC-curve analysis revealed high area-under-the-curve concordance with MetS by traditional criteria (0.96), and with elevations in MetS-associated risk markers, including high-sensitivity C-reactive protein (0.71), uric acid (0.75) and fasting insulin (0.82). Using a cut off for this score derived from ROC-curve analysis, the MetS risk score exhibited increased sensitivity for predicting elevations in ≥2 of these risk markers as compared with traditional pediatric MetS criteria.

Conclusions

The equations from this sex- and race/ethnicity-specific analysis provide a clinically-accessible and interpretable continuous measure of MetS that can be used to identify children at higher risk for developing adult diseases related to MetS, who could then be targeted for intervention. These equations also provide a powerful new outcome for use in childhood obesity and MetS research.

Ethnic differences in cardiometabolic risk profile at age 5-6 years: the ABCD study

BACKGROUND

To examine ethnic differences in cardiometabolic risk profile in early age, and explore whether such differences can be explained by differences in body mass index (BMI) or waist circumference (WC).

METHOD

Anthropometric measurements, blood pressure and (in a subsample) fasting blood were collected during a health check of 2,509 children aged 5-6 years. Four ethnic groups were distinguished: Dutch (n=2,008; blood n=1,300), African descent (n=199; blood n=105), Turkish (n=108; blood n=57) and Moroccan (n=194; blood n=94). Ethnic differences in diastolic and systolic blood pressure (DBP/SBP), fasting glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride levels were determined and the explanatory role of BMI and WC was examined with regression analysis.

RESULTS

After adjustment for confounders, African descent children showed higher DBP (β2.22 mmHg; 95%CI:1.09-3.36) and HDL levels (β:0.09 mmol/l; 95%CI:0.03-0.16) compared to Dutch children (reference group). Turkish children showed higher SBP (β:1.89 mmHg; 95%CI:0.25-3.54), DBP (β:2.62 mmHg; 95%CI:1.11-4.13), glucose (β:0.12 mmol/L; 95%CI:0.00-0.25) and triglyceride levels (β:0.13 mmol/L; 95%CI:0.02-0.25). Higher BMI values were found in all non-Dutch groups (differences ranged from 0.53-1.03 kg/m(2)) and higher WC in Turkish (β:1.68 cm; 95%CI:0.99-2.38) and Moroccan (β:1.65 cm; 95%CI:1.11-2.19) children. BMI and WC partly explained the higher SBP/DBP and triglyceride levels in Turkish children.

CONCLUSION

Ethnic differences in cardiometabolic profile exist early in life and are partly explained by differences in BMI and WC. African children showed favourable HDL levels and Turkish children the most unfavourable overall profile, whereas their Moroccan peers have less increased cardiometabolic risk in spite of their high BMI and WC.

Racial/ethnic and sex differences in the relationship between uric acid and metabolic syndrome in adolescents: an analysis of National Health and Nutrition Survey 1999-2006

Among adolescents, uric acid is associated with insulin resistance, hypertension, and the metabolic syndrome (MetS); and in adults, high uric acid levels are an independent risk factor for cardiovascular disease and diabetes. The objective was to determine whether the relationship of uric acid with MetS varies in adolescents by race/ethnicity and sex. We used linear regression to evaluate associations between uric acid and other MetS-associated clinical and laboratory measures among 3296 non-Hispanic white, non-Hispanic black, and Hispanic adolescents aged 12 to 19 years participating in the National Health and Nutrition Evaluation Survey (1999-2006). Overall, non-Hispanic white males and females had the highest uric acid levels among the 3 racial/ethnic groups. In each racial/ethnic group, there were higher uric acid levels for those adolescents with vs without MetS. However, the extent of the MetS-related increase in uric acid level varied by race and sex. Among males, MetS was associated with the greatest increases in uric acid among non-Hispanic whites. However, among females the MetS-related increase in uric acid was greater among non-Hispanic blacks and Hispanics. Non-Hispanic white females exhibited the lowest degrees of correlation between levels of uric acid and MetS-associated variables. Uric acid levels did not correlate with insulin levels in non-Hispanic white females. These data suggest that the relationship between uric acid and MetS varies by race/ethnicity and sex. In particular, non-Hispanic white males exhibit a strong relationship and non-Hispanic white females exhibit a relatively poor correlation between uric acid and MetS-related factors. These data may have implications for the use of uric acid as a marker of future risk among adolescents.

Distinguishing type 2 diabetes from type 1 diabetes in African American and Hispanic American pediatric patients

Objective

To test the hypothesis that clinical observations made at patient presentation can distinguish type 2 diabetes (T2D) from type 1 diabetes (T1D) in pediatric patients aged 2 to 18.

Subjects and Methods

Medical records of 227 African American and 112 Hispanic American pediatric patients diagnosed as T1D or T2D were examined to compare parameters in the two diseases. Age at presentation, BMI z-score, and gender were the variables used in logistic regression analysis to create models for T2D prediction.

Results

The regression-based model created from African American data had a sensitivity of 92% and a specificity of 89%; testing of a replication cohort showed 91% sensitivity and 93% specificity. A model based on the Hispanic American data showed 92% sensitivity and 90% specificity. Similarities between African American and Hispanic American patients include: (1) age at onset for both T1D and T2D decreased from the 1980s to the 2000s; (2) risk of T2D increased markedly with obesity. Racial/ethnic-specific observations included: (1) in African American patients, the proportion of females was significantly higher than that of males for T2D compared to T1D (p<0.0001); (2) in Hispanic Americans, the level of glycated hemoglobin (HbA1c) was significantly higher in T1D than in T2D (p<0.002) at presentation; (3) the strongest contributor to T2D risk was female gender in African Americans, while the strongest contributor to T2D risk was BMI z-score in Hispanic Americans.

Conclusions

Distinction of T2D from T1D at patient presentation was possible with good sensitivity and specificity using only three easily-assessed variables: age, gender, and BMI z-score. In African American pediatric diabetes patients, gender was the strongest predictor of T2D, while in Hispanic patients, BMI z-score was the strongest predictor. This suggests that race/ethnic specific models may be useful to optimize distinction of T1D from T2D at presentation.

Racial/ethnic and sex differences in the ability of metabolic syndrome criteria to predict elevations in fasting insulin levels in adolescents

OBJECTIVE

To evaluate racial/ethnic and sex differences in the relationship between metabolic syndrome (MetS) diagnosis and fasting insulin in adolescents.

STUDY DESIGN

We analyzed data from the National Health and Nutrition Evaluation Survey 1999-2008 for 3693 non-Hispanic-white, non-Hispanic-black, and Hispanic adolescents (12 to 19 years of age). We used linear regression to evaluate differences in fasting insulin levels between those with and without an adolescent adaptation of ATPIII-MetS in a sex- and race/ethnicity-specific basis.

RESULTS

Females had higher insulin levels than males, and non-Hispanic blacks and Hispanics had higher levels than non-Hispanic whites. Adolescents with MetS had higher insulin levels than those without MetS. The difference in insulin levels between those with and without MetS was greater in non-Hispanic blacks than in non-Hispanic whites (P < .05) but not Hispanics (P = .10). The sensitivity of MetS in detecting elevated insulin levels was lower in non-Hispanic blacks and females than in other ethnicities and males, respectively. Correlations between insulin and individual MetS components were similar among ethnicities.

CONCLUSION

MetS diagnosis performed more poorly in predicting elevated insulin levels in non-Hispanic blacks and in females. These data support the hypothesis that non-Hispanic blacks do not meet current criteria for MetS until they have reached a more advanced degree of insulin resistance.

Low sensitivity for the metabolic syndrome to detect uric acid elevations in females and non-Hispanic-black male adolescents: an analysis of NHANES 1999-2006

BACKGROUND

Uric acid is tightly linked to the metabolic syndrome (MetS) and among adults higher uric acid levels are associated with future risk for diabetes, cardiovascular disease, hypertension and renal disease.

OBJECTIVE

Evaluate the sensitivity of MetS to identify adolescents with elevated uric acid levels on a race/ethnicity and gender-specific basis.

METHODS

We evaluated 3296 male and female adolescents 12-19 y participating in the National Health and Nutrition Evaluation Survey 1999-06, comprised of 67.6% non-Hispanic whites, 15.1% non-Hispanic blacks, and 17.3% Hispanics. We used a definition of MetS modified for use in adolescents and evaluated the sensitivity of a diagnosis of MetS to identify individuals with uric acid elevations (approximately the 95th percentile of uric acid by gender among normal-weight adolescents).

RESULTS

When used as a screening test to identify individuals with uric acid elevations MetS performed more poorly among females (18.0%) than among males (37.0%) (p<0.001). Among males, MetS exhibited a lower sensitivity among non-Hispanic blacks (17.8%) compared to Hispanics (45.9%) (p<0.01) and non-Hispanic whites (37.4%) (p<0.05). There were no race/ethnicity differences in detecting elevated uric acid levels among females (non-Hispanic-white 15.5%, non-Hispanic-black 19.4%, Hispanic 26.5%, p>0.05).

CONCLUSION

Current criteria to diagnose MetS exhibit racial/ethnic and gender differences in the ability to identify adolescents with elevated uric acid levels, performing poorly among non-Hispanic-black males and among females. Given emerging data regarding the ability of uric acid elevations for predicting future disease, these data may have implications regarding the use of MetS as a marker of risk among all gender and racial/ethnic groups.

Predictors of Retention and BMI Loss or Stabilization in Obese Youth Enrolled in a Weight Loss Intervention

OBJECTIVE: To evaluate predictors for intervention dropout and successful reduction of metabolic syndrome risk factors among obese children enrolled in a short-term, clinic-based weight-loss intervention. DESIGN, SETTING, SUBJECTS: Retrospective database review of 1080 children 8 months-17 y.o. seen a a pediatric obesity clinic. INTERVENTIONS: Behavior modification counseling to induce change in dietary and exercise choices. MAIN OUTCOME MEASURES: 1). Pre-/post-intervention change in body mass index (BMI), waist circumference, blood pressure, glucose, insulin, and cholesterol (LDL, HDL, & total). 2) Predictors of successful decrease in BMI and clinic drop-out. ANALYSIS: Paired t-tests for pre-/post-intervention comparisons. Linear regression to assess predictors of success and predictors of drop-out, with adjustment for age, gender, race, insurance status, and service area. RESULTS: Among children evaluated, adolescent females were most likely to achieve successful decrease in BMI, insulin level, and LDL cholesterol post-intervention. Nearly 40% of children dropped out early in the intervention. Predictors of drop out included age <6y, public insurance status, follow-up scheduled during summer months, and residence in a tertiary service area. CONCLUSIONS: Clinic-based weight loss interventions can lead to successful improvements in BMI and other metabolic parameters in pediatric populations and may be more likely among adolescent females than in younger children or males. Drop-out is common, particularly among younger children, children with public insurance and children scheduled for follow-up in the summer. Identification of these drop-out predictors in individual patients may help in targeting children likely to succeed in short-term, clinic-based, weight-loss interventions.

O-linked-N-acetylglucosamine cycling and insulin signaling are required for the glucose stress response in Caenorhabditis elegans

In a variety of organisms, including worms, flies, and mammals, glucose homeostasis is maintained by insulin-like signaling in a robust network of opposing and complementary signaling pathways. The hexosamine signaling pathway, terminating in O-linked-N-acetylglucosamine (O-GlcNAc) cycling, is a key sensor of nutrient status and has been genetically linked to the regulation of insulin signaling in Caenorhabditis elegans. Here we demonstrate that O-GlcNAc cycling and insulin signaling are both essential components of the C. elegans response to glucose stress. A number of insulin-dependent processes were found to be sensitive to glucose stress, including fertility, reproductive timing, and dauer formation, yet each of these differed in their threshold of sensitivity to glucose excess. Our findings suggest that O-GlcNAc cycling and insulin signaling are both required for a robust and adaptable response to glucose stress, but these two pathways show complex and interdependent roles in the maintenance of glucose-insulin homeostasis.

Ethnicity, obesity and the metabolic syndrome: implications on assessing risk and targeting intervention

Pediatric obesity threatens the future health of a growing number of children worldwide. An added challenge in identifying the patients at greatest need for intervention due to their elevated risk for future disease is that pediatric obesity and the associated metabolic syndrome manifest differently among different ethnic groups. African-Americans and Hispanics are more likely to exhibit obesity and insulin resistance and are at a higher risk for developing Type 2 diabetes. Nevertheless, using current criteria, African-American adolescents are much less likely to be diagnosed with metabolic syndrome, largely owing to lower rates of dyslipidemia. Further development is needed in ethnicity-inclusive means of risk identification among adolescents to accurately target treatment toward children at highest risk for future disease and to motivate adolescent patients and their families towards lifestyle improvement. Effective targeting and intensive treatment efforts may help in avoiding future sequelae of obesity among all ethnicities.

Diagnosis of the metabolic syndrome is associated with disproportionately high levels of high-sensitivity C-reactive protein in non-Hispanic black adolescents: an analysis of NHANES 1999-2008

OBJECTIVE

Whereas it is known that the metabolic syndrome (MetS) has a paradoxically lower prevalence in non-Hispanic black adolescents than in non-Hispanic whites or Hispanics, the relative severity of MetS by race/ethnicity is unknown. Inflammation, indicated by high-sensitivity C-reactive protein (hsCRP), is a key factor linking MetS to cardiovascular disease and type 2 diabetes. Our goal was to determine whether elevations of hsCRP vary by race/ethnicity among adolescents with MetS.

RESEARCH DESIGN AND METHODS

We used the National Health and Nutrition Examination Survey (1999-2008) and evaluated adolescents (age 12-19 years) using a pediatric/adolescent adaptation of the ATP III definition of MetS. We used linear regression to evaluate the interaction between MetS status and ethnicity with respect to hsCRP concentration.

RESULTS

For male and female adolescents, MetS was associated with elevated hsCRP levels compared with adolescents without MetS. However, the elevation in hsCRP between adolescents with and without MetS was greater in non-Hispanic blacks compared with that in non-Hispanic whites (P = 0.04) but not that in Hispanics (P = 0.18). hsCRP concentrations correlated with individual MetS components similarly among all ethnicities. In an evaluation of adolescents diagnosed with MetS, non-Hispanic blacks had higher BMI and more hypertension than other ethnicities but there were no other racial/ethnic differences in the features of MetS.

CONCLUSIONS

Non-Hispanic black adolescents have a greater differential in hsCRP between those with and those without MetS than the differential in non-Hispanic whites but not that in Hispanics. Therefore, even though MetS has a low prevalence in non-Hispanic blacks, MetS is a particularly good indicator of inflammation in non-Hispanic black adolescents.

Ability among adolescents for the metabolic syndrome to predict elevations in factors associated with type 2 diabetes and cardiovascular disease: data from the national health and nutrition examination survey 1999-2006

OBJECTIVE

The aim of this study was to compare currently proposed sets of pediatric metabolic syndrome criteria for the ability to predict elevations in "surrogate" factors that are associated with metabolic syndrome and with future cardiovascular disease and type 2 diabetes mellitus. These surrogate factors were fasting insulin, hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein (hsCRP), and uric acid.

METHODS

Waist circumference (WC), blood pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), fasting glucose, fasting insulin, HbA1c, hsCRP, and uric acid measurements were obtained from 2,624 adolescent (12-18 years old) participants of the 1999-2006 National Health and Nutrition Examination Surveys. We identified children with metabolic syndrome as defined by six commonly used sets of pediatric metabolic syndrome criteria. We then defined elevations in the surrogate factors as values in the top 5% for the cohort and calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each set of metabolic syndrome criteria and for each surrogate factor.

RESULTS

Current pediatric metabolic syndrome criteria exhibited variable sensitivity and specificity for surrogate predictions. Metabolic syndrome criteria had the highest sensitivity for predicting fasting insulin (40-70%), followed by uric acid (31-54%), hsCRP (13-31%), and HbA1c (7-21%). The criteria of de Ferranti (which includes children with WC >75(th) percentile, compared to all other sets including children with WC >90(th) percentile) exhibited the highest sensitivity for predicting each of the surrogates, with only modest decrease in specificity compared to the other sets of criteria. However, the de Ferranti criteria also exhibited the lowest PPV values. Conversely, the pediatric International Diabetes Federation criteria exhibited the lowest sensitivity and the highest specificity.

CONCLUSIONS

Pediatric metabolic syndrome criteria exhibit moderate sensitivity for detecting elevations in surrogate factors associated with metabolic syndrome and with risk for future disease. Inclusion of children with more modestly elevated WC improved sensitivity.