Anne E. Sumner

A better index of body adiposity.

Obesity is a growing problem in the United States and throughout the world. It is a risk factor for many chronic diseases. The BMI has been used to assess body fat for almost 200 years. BMI is known to be of limited accuracy, and is different for males and females with similar %body adiposity. Here, we define an alternative parameter, the body adiposity index (BAI = ((hip circumference)/((height)1.5)–18)). The BAI can be used to reflect %body fat for adult men and women of differing ethnicities without numerical correction. We used a population study, the “BetaGene” study, to develop the new index of body adiposity. %Body fat, as measured by the dual‐energy X‐ray absorptiometry (DXA), was used as a “gold standard” for validation. Hip circumference (R = 0.602) and height (R = −0.524) are strongly correlated with %body fat and therefore chosen as principal anthropometric measures on which we base BAI. The BAI measure was validated in the “Triglyceride and Cardiovascular Risk in African‐Americans (TARA)” study of African Americans. Correlation between DXA‐derived %adiposity and the BAI was R = 0.85 for TARA with a concordance of C_b = 0.95. BAI can be measured without weighing, which may render it useful in settings where measuring accurate body weight is problematic. In summary, we have defined a new parameter, the BAI, which can be calculated from hip circumference and height only. It can be used in the clinical setting even in remote locations with very limited access to reliable scales. The BAI estimates %adiposity directly.

MINMOD Millennium: A Computer Program to Calculate Glucose Effectiveness and Insulin Sensitivity from the Frequently Sampled Intravenous Glucose Tolerance Test

The Bergman Minimal Model enables estimation of two key indices of glucose/insulin dynamics: glucose effectiveness and insulin sensitivity. In this paper we describe MINMOD Millennium, the latest Windows-based version of minimal model software. Extensive beta testing of MINMOD Millennium has shown that it is user-friendly, fully automatic, fast, accurate, reproducible, repeatable, and highly concordant with past versions of MINMOD. It has a simple interface, a comprehensive help system, an input file editor, a file converter, an intelligent processing kernel, and a file exporter. It provides publication-quality charts of glucose and insulin and a table of all minimal model parameters and their error estimates. In contrast to earlier versions of MINMOD and some other minimal model programs, Millennium provides identified estimates of insulin sensitivity and glucose effectiveness for almost every subject.

Hypertrophy and/or Hyperplasia: Dynamics of Adipose Tissue Growth

Adipose tissue grows by two mechanisms: hyperplasia (cell number increase) and hypertrophy (cell size increase). Genetics and diet affect the relative contributions of these two mechanisms to the growth of adipose tissue in obesity. In this study, the size distributions of epididymal adipose cells from two mouse strains, obesity-resistant FVB/N and obesity-prone C57BL/6, were measured after 2, 4, and 12 weeks under regular and high-fat feeding conditions. The total cell number in the epididymal fat pad was estimated from the fat pad mass and the normalized cell-size distribution. The cell number and volume-weighted mean cell size increase as a function of fat pad mass. To address adipose tissue growth precisely, we developed a mathematical model describing the evolution of the adipose cell-size distributions as a function of the increasing fat pad mass, instead of the increasing chronological time. Our model describes the recruitment of new adipose cells and their subsequent development in different strains, and with different diet regimens, with common mechanisms, but with diet- and genetics-dependent model parameters. Compared to the FVB/N strain, the C57BL/6 strain has greater recruitment of small adipose cells. Hyperplasia is enhanced by high-fat diet in a strain-dependent way, suggesting a synergistic interaction between genetics and diet. Moreover, high-fat feeding increases the rate of adipose cell size growth, independent of strain, reflecting the increase in calories requiring storage. Additionally, high-fat diet leads to a dramatic spreading of the size distribution of adipose cells in both strains; this implies an increase in size fluctuations of adipose cells through lipid turnover.

Efficacy and Safety of Troglitazone in the Treatment of Lipodystrophy Syndromes

Obesity causes insulin resistance, a central feature in the pathogenesis of type 2 diabetes (1). Paradoxically, the absence of adipose tissue also causes insulin resistance and diabetes in humans (2, 3) and genetically engineered animal models (4-6). Lipoatrophy and lipodystrophy are features of a group of heterogeneous syndromes characterized by a paucity of fat, insulin resistance, and hypertriglyceridemia (7). If patients develop diabetes, the syndrome is referred to as lipoatrophic diabetes. The disease has several genetic forms, including face-sparing partial lipoatrophy (the Dunnigan syndrome or the KoberlingDunnigan syndrome, OMIM [Online Mendelian Inheritance in Man] 308980), an autosomal dominant form caused by mutations in the lamin A/C gene (8), and congenital generalized lipoatrophy (the SeipBerardinelli syndrome, OMIM 269700), an autosomal recessive form mapping to chromosome 9q34 in some pedigrees (9). These diseases are rare; reported estimated prevalences are less than 1 in 10 million (10), although our experience suggests that the actual prevalences may be somewhat higher. An association between lipoatrophy and autoimmune disease, such as juvenile dermatomyositis, has also been described (11), suggesting that autoimmune destruction of adipose tissue results in a form of lipoatrophy. Thiazolidinediones, a new class of antidiabetic drugs (12), are ligands for peroxisome proliferatoractivated receptor- (PPAR-), a nuclear receptor expressed predominantly in adipose tissue (13). Thiazolidinediones are believed to exert their primary actions in adipose tissue and to indirectly increase insulin sensitivity in other tissues (14). Because thiazolidinediones have been reported to both increase insulin sensitivity (15, 16) and promote adipocyte development (17), these drugs seemed ideally suited to treat lipoatrophic diabetes. Troglitazone, the first thiazolidinedione to be approved for therapeutic use in the United States, has been shown to improve glycemic control and ameliorate hypertriglyceridemia in patients with type 2 diabetes (18). However, the use of troglitazone is complicated by a rare form of severe, irreversible hepatotoxicity. Two additional thiazolidinediones, rosiglitazone and pioglitazone, were recently approved for use. These drugs are also effective in improving glycemic control in patients with type 2 diabetes (19). Although initial studies of rosiglitazone and pioglitazone suggested that they might not be toxic to the liver, recent reports have raised the possibility that rosiglitazone may rarely cause hepatotoxicity (19, 20). Because PPAR- ligands promote adipocyte differentiation in vitro (13), we hypothesized that troglitazone would promote adipocyte development in patients with various forms of lipoatrophy. This hypothesis implicitly assumes that some lipoatrophic patients possess pre-adipocytes that could be stimulated by troglitazone to complete adipocyte differentiation. In addition, we sought to determine whether troglitazone therapy would improve metabolic control in patients with various forms of lipoatrophy. In light of data suggesting that troglitazone exerts its primary effects on adipocytes, it was uncertain whether the drug would be effective in such patients. Methods Patients Potential study participants were referred by multiple physicians in the United States and Canada in response to advertisements placed in medical journals, notices on the Internet, or word-of-mouth. Some patients had been followed at the National Institutes of Health for varying periods of time (up to 20 years). Because of the rarity of the syndrome, it was not practical to conduct population-based recruitment. To be eligible for the study, patients had to have both insulin resistance and lipoatrophy. For our purposes, insulin resistance was defined as either a fasting plasma insulin level greater than 143 pmol/L or impaired response to intravenous insulin (0.15 U/kg). The latter criterion was defined as a decrease in plasma glucose of less than 50% in patients with fasting glucose levels of 11 mmol/L or less ( 200 mg/dL) or a decrease of 5.5 mmol/L or less (<100 mg/dL) in patients with fasting glucose levels greater than 11.1 mmol/L (>200 mg/dL). Of 33 patients screened for this study, 8 were excluded because serum aminotransferase concentrations were abnormal (range, 833 to 6666 nkat/L) and liver biopsies showed steatohepatitis with varying degrees of fibrosis. Five patients were excluded for various reasons, such as the inability to give informed consent or adhere to the study follow-up schedule. The remaining 20 patients were recruited into the study (Table). Table. Characteristics of the Study Patients Fat distribution was assessed by physical examination and magnetic resonance imaging (MRI). A region of the body was defined as affected if MRI showed a marked decrease in fat in that region. Four patients had generalized lipoatrophy, defined as involvement of the following nine regions: face, neck, upper trunk, abdominal subcutaneous fat, visceral fat, and all four extremities. Two of these patients (U1 and P1) had near-total absence of fat throughout their bodies; the other two (A1 and A2) had a generalized decrease in fat but retained some fat in their visceral abdomen. Sixteen patients, including 7 patients with the Dunnigan syndrome, had partial lipoatrophy affecting five to eight fat depots. Six patients had accompanying autoimmune disease or results on three or more laboratory tests that suggested autoimmunity (for example, antinuclear antibody, rheumatoid factor, and elevated erythrocyte sedimentation rate); these patients therefore were presumed to have an autoimmune cause of their lipoatrophy. The cause of lipoatrophy appeared to be genetic in 10 patients; lipoatrophy appeared shortly after birth in 1 patient, and 9 patients had several affected relatives. Seven of these 9 patients had Dunnigan partial lipodystrophy (21) (Table); the 7 patients were members of three pedigrees. After completion of the study, the diagnosis of the Dunnigan syndrome was confirmed by identifying the R482Q mutation in the lamin A/C gene in all three pedigrees (22). In 4 patients, the cause of disease was unknown. Of the 20 study patients (Table), 14 had diabetes and 2 had impaired glucose tolerance according to the 1997 American Diabetes Association criteria (23). Most diabetic patients were receiving pharmacotherapy before study entry. Five patients were receiving insulin (0.5 to 2 U/kg of body weight per day) and 5 were receiving sulfonylureas; patients continued to receive these therapies during the study. Two patients were receiving metformin, but this therapy was discontinued 6 weeks before initiation of troglitazone treatment. Syndromes of lipoatrophy are associated with substantial comorbid conditions. Of the 8 patients with triglyceride levels greater than 4.5 mmol/L (400 mg/dL), 6 had a history of pancreatitis. Seventeen patients had acanthosis nigricans, a dermatologic condition associated with insulin resistance. Twelve of the 18 female participants had histories of irregular menses and polycystic ovaries as documented by ultrasonography; 6 of these women had hirsutism. Of the 6 remaining female participants, 4 were postmenopausal, 1 was perimenopausal, and 1 was prepubertal. Fatty liver is another important feature sometimes associated with lipoatrophy. To be included in the study, patients had to have normal biochemical function of the liver (Table). Nevertheless, results of ultrasonography in 12 patients suggested fatty infiltration of the liver. Lipoatrophic diabetes was associated with chronic complications of diabetes in some patients. Six patients had albuminuria, seven had diabetic polyneuropathy, and three had diabetic retinopathy (one of whom had proliferative retinopathy). One patient had three-vessel coronary artery disease. Design Patients were treated with troglitazone in an open-label prospective trial in which each patient was compared with his or her own baseline state. Because of the rarity of lipoatrophy syndromes and the variability of the clinical features, it was not feasible to use a randomized, placebo-controlled design. The study was approved by the institutional review board of the National Institute of Diabetes and Digestive and Kidney Diseases. Informed consent was obtained from the patient or his or her legal guardian. The decision to analyze the data after 6 months of therapy was made before the study was begun. Patients were evaluated as inpatients at the Clinical Center of the National Institutes of Health before treatment with troglitazone was initiated. They were admitted again after 6 weeks, 3 months, and 6 months of treatment. Before starting troglitazone therapy, diabetic patients were followed for at least 6 weeks while receiving stable doses of medication. Patients receiving insulin or sulfonylureas continued therapy with these drugs; however, metformin therapy was discontinued before troglitazone therapy was initiated. In diabetic patients, troglitazone therapy was started at a dosage of 200 mg/d and was increased to 400 to 600 mg/d over the course of 6 to 12 weeks, with the goal of optimizing glycemic control. The slow titration was chosen to minimize the risk for hypoglycemia. Doses of insulin or sulfonylureas were decreased if this was necessary to prevent hypoglycemia. Patients received stable doses of lipid-lowering medication for at least 6 weeks before starting troglitazone therapy. In nondiabetic adult participants, troglitazone was prescribed at a dosage of 400 mg/d. In one 6-year-old child weighing 15 to 18 kg, the dosage was 100 mg/d. Liver function tests and blood counts were performed every 3 to 4 weeks. Patients completed weekly questionnaires about their symptoms to identify potential side effects. Patients were instructed not to change their diet and exercise habits during this study. Information about dietary habits was collected by using

Protection from obesity and diabetes by blockade of TGF-β/Smad3 signaling

Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-β/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3-deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3(-)(/-) white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3(-/-) adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-1α expression. We observe significant correlation between TGF-β1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-β signaling protects mice from obesity, diabetes, and hepatic steatosis. Together, these results demonstrate that TGF-β signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-β activity might be an effective treatment strategy for obesity and diabetes.

Health Disparities in Endocrine Disorders: Biological, Clinical, and Nonclinical Factors—An Endocrine Society Scientific Statement

OBJECTIVE The aim was to provide a scholarly review of the published literature on biological, clinical, and nonclinical contributors to race/ethnic and sex disparities in endocrine disorders and to identify current gaps in knowledge as a focus for future research needs. PARTICIPANTS IN DEVELOPMENT OF SCIENTIFIC STATEMENT: The Endocrine Societys Scientific Statement Task Force (SSTF) selected the leader of the statement development group (S.H.G.). She selected an eight-member writing group with expertise in endocrinology and health disparities, which was approved by the Society. All discussions regarding the scientific statement content occurred via teleconference or written correspondence. No funding was provided to any expert or peer reviewer, and all participants volunteered their time to prepare this Scientific Statement. EVIDENCE The primary sources of data on global disease prevalence are from the World Health Organization. A comprehensive literature search of PubMed identified U.S. population-based studies. Search strategies combining Medical Subject Headings terms and keyword terms and phrases defined two concepts: 1) racial, ethnic, and sex differences including specific populations; and 2) the specific endocrine disorder or condition. The search identified systematic reviews, meta-analyses, large cohort and population-based studies, and original studies focusing on the prevalence and determinants of disparities in endocrine disorders. consensus process: The writing group focused on population differences in the highly prevalent endocrine diseases of type 2 diabetes mellitus and related conditions (prediabetes and diabetic complications), gestational diabetes, metabolic syndrome with a focus on obesity and dyslipidemia, thyroid disorders, osteoporosis, and vitamin D deficiency. Authors reviewed and synthesized evidence in their areas of expertise. The final statement incorporated responses to several levels of review: 1) comments of the SSTF and the Advocacy and Public Outreach Core Committee; and 2) suggestions offered by the Council and members of The Endocrine Society. CONCLUSIONS Several themes emerged in the statement, including a need for basic science, population-based, translational and health services studies to explore underlying mechanisms contributing to endocrine health disparities. Compared to non-Hispanic whites, non-Hispanic blacks have worse outcomes and higher mortality from certain disorders despite having a lower (e.g. macrovascular complications of diabetes mellitus and osteoporotic fractures) or similar (e.g. thyroid cancer) incidence of these disorders. Obesity is an important contributor to diabetes risk in minority populations and to sex disparities in thyroid cancer, suggesting that population interventions targeting weight loss may favorably impact a number of endocrine disorders. There are important implications regarding the definition of obesity in different race/ethnic groups, including potential underestimation of disease risk in Asian-Americans and overestimation in non-Hispanic black women. Ethnic-specific cut-points for central obesity should be determined so that clinicians can adequately assess metabolic risk. There is little evidence that genetic differences contribute significantly to race/ethnic disparities in the endocrine disorders examined. Multilevel interventions have reduced disparities in diabetes care, and these successes can be modeled to design similar interventions for other endocrine diseases.

Elevated Methylmalonic Acid and Total Homocysteine Levels Show High Prevalence of Vitamin B12 Deficiency after Gastric Surgery

Elderly persons [1, 2] and persons who have had gastric surgery [3-11] are at increased risk for developing vitamin B12 (cobalamin) deficiency. The hematologic and neurologic manifestations of vitamin B12 deficiency have been well described; however, this deficiency often remains undetected, and some patients receive a misdiagnosis of Alzheimer disease, spinal cord compression, amyotrophic lateral sclerosis, or diabetic or alcoholic peripheral neuropathy [12]. Although megaloblastic anemia is usually reversible with vitamin B12 treatment, the neurologic injuries are reversible only if they are treated soon after their onset [12, 13]. In addition, as do patients with folate deficiency [14], patients with untreated vitamin B12 deficiency have elevated total homocysteine levels. Substantial biochemical and epidemiologic evidence now suggests that an elevated serum total homocysteine level contributes to the development of carotid artery stenosis, coronary artery disease, and peripheral vascular disease [15-18]. Thus, in theory at least, patients with untreated vitamin B12 deficiency may be at increased risk for developing atherosclerotic vascular disease. In the future, the prevalence of vitamin B12 deficiency in the aging population may be expected to increase. Among persons at major risk are those who had subtotal gastrectomy for ulcer disease between the 1930s [19] and 1974 [5, 7] (in 1974, the first histamine-2 blocker, cimetidine, was released [20]). It is not possible to determine how many Americans had gastric surgery during this period, but representative data from the University of Minnesota Hospital suggest that the number is large. At that hospital alone, 1550 patients had subtotal gastrectomy between 1938 and 1950 [4]. Throughout the United States, therefore, hundreds of thousands of patients probably had this surgery. A new operation, gastric bypass for obesity, is currently creating another cohort at risk for developing vitamin B12 deficiency [11]. As these cohorts age, an unknown number of persons will develop vitamin B12 deficiency, and clinicians caring for such persons currently have no accurate guidelines on which to base screening decisions. Previous prevalence estimates are unreliable because clinical manifestations are insensitive and radiodilution vitamin B12 assays were nonspecific [21, 22]. The Schilling test is unreliable after gastrectomy [8, 9], anemia is often absent in vitamin B12-deficient patients [2, 12, 23], and macrocytosis may be masked by coexisting iron deficiency [7, 24]. See editorial comment on pp 509-511. Recently, however, measurements of the metabolites from two vitamin B12-dependent pathways (Figure 1)serum methylmalonic acid [25] and total homocysteine [14]were shown to be highly sensitive detectors of vitamin B12 deficiency [26]. Two enzymes have a known requirement for vitamin B12: L-methylmalonyl-CoA mutase and methionine synthase [22]. Methionine synthase requires folate in addition to vitamin B12 for normal functioning. If the conversion of L-methylmalonyl-CoA to succinyl-CoA is impaired by a deficiency of the vitamin B12 cofactor adenosylcobalamin, the excess methylmalonyl-CoA is cleaved to methylmalonic acid and methylmalonic acid levels in the serum and urine are elevated [25]. Similarly, if the methylation of homocysteine to methionine is impaired by a deficiency of methylcobalamin or methyltetrahydrofolate, serum total homocysteine levels are elevated [14]. The metabolic pathways in which these two enzymes function are not always equally affected by vitamin B12 deficiency. At the time vitamin B12 deficiency is diagnosed, therefore, levels of methylmalonic acid, total homocysteine, or both may be elevated [22]. Figure 1. The two vitamin B12-dependent enzymes, L-methylmalonyl-CoA mutase (left) and methionine synthase (right). In vitamin B12-deficient patients, elevated levels of both serum methylmalonic acid and total homocysteine decrease promptly with adequate vitamin B12 therapy [22, 26]. However, in folate-deficient patients, total homocysteine levels return to normal only after folate replacement [22]. Therefore, in addition to serum vitamin B12 levels, we used methylmalonic acid, total homocysteine, and folate levels to determine whether the prevalence of vitamin B12 deficiency differed between persons who had had gastric surgery and those who had not. Methods Between September 1991 and March 1993, 65 patients who had had gastric surgery were identified at the Philadelphia Veterans Affairs Medical Center. These patients were identified either by review of gastrointestinal radiographs, surveys of the house-staff assigned to the medicine and surgery inpatient services, or referral of outpatients from physicians in the medical clinic. Four of the 65 patients were excluded: Three were receiving vitamin B12 therapy, and one had a hepatoma. Hepatoma can produce increased levels of vitamin B12-binding protein, which may complicate interpretation of serum vitamin B12 levels. Patients who had not had gastric surgery (controls) were drawn from 127 consecutive patients attending one authors Philadelphia Veterans Affairs Medical Center clinic between November 1992 and March 1993. One hundred seven controls participated, and 20 either declined to participate or did not complete the required blood tests. We determined the type of gastric surgery that had been done either from patient reporting or by reviewing radiologic, endoscopic, or surgical records. In most patients (51 of 61), we determined the year surgery had been done from patient report or chart review. For patients who could not provide the year of surgery but could specify the decade, we used the mid-decade year. For example, if the patient said that the surgery had been done in the 1950s, we recorded the year as 1955. Serum vitamin B12 and folate levels were determined at the Philadelphia Veterans Affairs Medical Center using a commercially available radioligand kit (Bio-Rad, Diagnostics Group, Hercules, California). In the hospitals laboratory, normal values for vitamin B12 and folate levels were 171 to 840 pmol/L and 5 to 39 nmol/L, respectively. The remaining serum samples were frozen at 20 C and were shipped to Denver so that serum methylmalonic acid and total homocysteine levels could be analyzed by the stable isotope dilution gas chromatography-mass spectrometry method [27-30]. The normal range for serum methylmalonic acid levels (determined in 50 normal blood donors 18 to 65 years of age) is 73 to 271 nmol/L, and the normal range for serum total homocysteine levels is 5.4 to 16.2 mol/L [22]. Vitamin B12 deficiency was defined as one of the following: 1) a serum vitamin B12 level less than 221 pmol/L and an elevated methylmalonic acid level; 2) a serum vitamin B12 level less than 221 pmol/L and a total homocysteine level that decreased after vitamin B12 therapy; or 3) in patients unavailable for treatment, a serum vitamin B12 level less than 221 pmol/L, a folate level greater than 9 nmol/L, and an elevated total homocysteine level. Hemoglobin level, hematocrit, and mean corpuscular volume were measured by automatic devices. Macrocytosis was defined as a mean corpuscular volume of 95 fL or less. The peripheral smears of 71% of patients (43 of 61) and 88% of controls (94 of 107) were reviewed by one hematologist who was blinded to each participants vitamin B12 level, hemoglobin level, hematocrit, and gastric surgery status. Hypersegmentation was defined as five neutrophils with five or more lobes or one neutrophil with six lobes per 100 cells counted. Treatment Vitamin B12 treatment generally consisted of daily intramuscular injections of 1000 g of vitamin B12 for 5 days, followed by monthly injections. Folic acid was given orally, 1 mg/d. Serum vitamin B12, folate, methylmalonic acid, and total homocysteine levels were measured 1 to 6 weeks after treatment. Statistical Analysis Data were examined to determine whether the variables were suitable for parametric analyses. Although relatively modest, the skew for the numeric variables necessitated that several variables be transformed to logs for entry into two-way analysis of variance or be subjected to nonparametric analyses. The comparison between patients and controls for levels of vitamin B12, folate, methylmalonic acid, and total homocysteine was done by two-factor analysis of variance on log-transformed variables. In each analysis of variance, race was included as a factor (along with study group) to control for possible race-by-group interactions. We used unpaired t-tests or Mann-Whitney U tests to do comparisons of other numeric variables, such as hemoglobin and mean corpuscular volume; comparisons between other groups, such as patients with a positive and patients with a negative peripheral blood smear; and comparisons between deficient and nondeficient patients. We used chi-square tests to compare groups on dichotomous variables (such as white patients compared with black patients). Spearman correlations were used to assess the association between the time since surgery and other variables. The Human Studies Subcommittee and the Research and Development Committee of the Philadelphia Veterans Affairs Medical Center approved the study. Results Clinical Characteristics The 61 patients (who had had gastric surgery) and 107 controls (who had not) were similar in the ratio of men to women (60:1 compared with 104:3), age, and race (Table 1). The indications for surgery included peptic ulcer disease (56 patients), obesity (3 patients), gastric cancer (3 patients [2 of whom had previously had surgery for peptic ulcer disease]), and gastric lymphoma (1 patient). The type of gastric surgery could be determined in 36 of 61 patients (59%). The types of surgery were Billroth II (23 patients), repair of perforated ulcer (6 patients), vagotomy and pyloroplasty (2 patients), gastric bypass or gastric banding for obesity (3 patients), Billroth I (1 patient),

Ethnic differences in triglyceride levels and high-density lipoprotein lead to underdiagnosis of the metabolic syndrome in black children and adults.

The metabolic syndrome was designed to identify individuals at high risk for the development of type 2 diabetes and cardiovascular disease. Compared with whites, blacks have higher rates of diabetes and cardiovascular disease. Paradoxically, blacks have a lower prevalence of the metabolic syndrome. According to the criteria set by National Cholesterol Education Treatment Program-Adult Treatment Panel III, to diagnose the metabolic syndrome, 3 of 5 characteristics must be present. These characteristics are low high-density lipoprotein levels, increased triglyceride levels, central obesity, hypertension, and fasting hyperglycemia. Examining each of these factors individually, blacks are more likely than whites to have obesity, hypertension, and diabetes. In contrast, blacks are less likely than whites to have either elevated triglyceride or low high-density lipoprotein levels. Ethnic differences in lipid levels may largely explain why blacks have a lower than expected prevalence of the metabolic syndrome. In this review we will describe in children and adults ethnic differences in the epidemiologic study of conditions associated with the metabolic syndrome, as well as focus on each of the parameters of the metabolic syndrome. Overall, we conclude that an ethnic-specific formulation of the lipid criteria in the metabolic syndrome may lead to better identification of blacks at high risk for development of diabetes and cardiovascular disease.

Obesity, physical inactivity, and risk for cardiovascular disease.

Despite considerable progress in understanding disease mechanisms and risk factors, improved treatments, and public education efforts, cardiovascular disease (CVD) remains the leading cause of death in the United States. Obesity and physical inactivity, 2 important lifestyle-related risk factors for CVD, are prevalent in the southeastern United States and are becoming more prevalent in all racial groups and areas of the country. In reviewing these risk factors, we explored topics including prevalence and trends in population data; associated psychosocial and environmental factors; and some of the mechanisms through which these risk factors are thought to contribute to CVD. We identified significant, but as yet poorly understood, racial disparities in prevalence of obesity, low levels of physical activity, and correlates of these risk factors and examined important differences in the complex relationship between obesity, diabetes, and cardiovascular disease risk between African American and European American women. The Jackson Heart Study will provide important and unique information relevant to many unanswered questions about obesity, physical inactivity, and obesity in African Americans.

Sex Differences in the Cardiovascular Consequences of Diabetes Mellitus A Scientific Statement From the American Heart Association

The prevalence of diabetes mellitus (DM) is increasing at a rapid rate. In the United States in 2012, 29.1 million Americans, or 9.3% of the population, had DM.1 Currently, ≈1 in 13 people living in the United States has DM, and 90% to 95% of these individuals have type 2 DM (T2DM).2 Overall, the prevalence of T2DM is similar in women and men. In the United States, ≈12.6 million women (10.8%) and 13 million men (11.8%) ≥20 years of age are currently estimated to have T2DM.2 Among individuals with T2DM, cardiovascular disease (CVD) is the leading cause of morbidity and mortality and accounts for >75% of hospitalizations and >50% of all deaths.3 Although nondiabetic women have fewer cardiovascular events than nondiabetic men of the same age, this advantage appears to be lost in the context of T2DM.4,5 The reasons for this advantage are not entirely clear but are likely multifactorial with contributions from inherent physiological differences, including the impact of the sex hormones, differences in cardiovascular risk factors, and differences between the sexes in the diagnosis and treatment of DM and CVD.6 In addition, there are racial and ethnic factors to consider because women of ethnic minority backgrounds have a higher prevalence of DM than non-Hispanic white (NHW) women. This scientific statement was designed to provide the current state of knowledge about sex differences in the cardiovascular consequences of DM, and it will identify areas that would benefit from further research because much is still unknown about sex differences in DM and CVD. Areas that are discussed include hormonal differences between the sexes and their possible effects on the interaction between DM and CVD, sex differences in epidemiology, ethnic and racial differences and risk factors for CVD in DM across the life …