Defining obesity cut points in a multiethnic population

Non-alcoholic fatty liver disease and its association with obesity, insulin resistance and increased serum levels of C-reactive protein in Hispanics

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder of the liver, which may progress to fibrosis or cirrhosis. Recent studies have shown a significant impact of ethnicity on susceptibility to steatosis-related liver disease.

AIMS

To estimate the prevalence of NAFLD among Chilean Hispanics as well as the clinical and biochemical variables associated with the disease.

METHODS

Population-based study among Chilean Hispanics. The diagnosis of NAFLD was made on the basis of ultrasound evidence of fatty liver and absence of significant alcohol consumption and hepatitis C virus infection.

RESULTS

A total of 832 Hispanic subjects were included. Ultrasound findings revealed diffuse fatty liver in 23% of the subjects. Variables associated with fatty liver in multivariate analysis were body mass index >26.9 [odds ratio (OR) 6.2; 95% confidence interval (CI) 3.3-11.5], abnormal aspartate aminotransferase levels (OR 14; 95% CI 8.2-23.7), presence of insulin resistance as measured by homoeostasis model assessment-insulin resistance (OR 3; 95% CI 1.8-4.8) and serum levels of high-sensitivity C-reactive protein (hs-CRP) greater than 0.86 mg/L (OR 2.9; 95% CI 1.6-5.2). Among subjects with NAFLD, levels of hs-CRP were similar regardless of the alanine aminotransferase (ALT) level.

CONCLUSIONS

Chilean Hispanics exhibit a high prevalence of NAFLD. Obesity, insulin resistance, abnormal aminotransferase levels and elevated hs-CRP were independently associated with the presence of NAFLD. ALT elevation underestimates the presence of ultrasonographical fatty liver, whereas hs-CRP is a sensitive independent marker of NAFLD, which may be useful for detecting fatty liver in the general population.

Adiposity and pathogen exposure predict C-reactive protein in Filipino women

Obesity and infectious agents are both sources of inflammatory stimuli that result in increased production of C-reactive protein (CRP). Rates of overweight and obesity are increasing globally, but for many populations, gains in body fat are set against a backdrop of high levels of pathogen exposure. Our primary objective was to evaluate the extent to which adiposity and pathogenicity contribute to a double burden of inflammation in a population currently undergoing the nutrition transition. Measures of adiposity, pathogen exposure, and infectious disease symptoms were evaluated as predictors of high-sensitivity CRP concentration in plasma samples from 1875 women participating in the Cebu Longitudinal Health and Nutrition Survey in the Philippines. Proxy measures of pathogen exposure included household crowding and cleanliness, quality of water source, mode of waste disposal, and fecal exposure. A series of maximum likelihood logistic regression models were used to predict a plasma CRP concentration > 3 mg/L. Waist circumference was the strongest anthropometric predictor of elevated CRP [odds ratio (OR) = 2.29; 95% CI = 2.00, 2.62; P < 0.001]. Presence of infectious disease symptoms (OR = 2.51; 95% CI = 1.84, 3.44; P < 0.001) and level of pathogen exposure (OR = 1.56; 95% CI = 1.15, 2.12; P < 0.01) were also associated with elevated CRP. These associations were independent of socioeconomic status and other health behaviors. Overweight/obesity and infectious exposures are associated with elevated CRP in the Philippines; it is likely that other populations undergoing the nutrition transition are experiencing comparable double burdens of inflammatory stimuli. These results underscore the need for additional research on the contributions of pathogenicity, adiposity, and inflammation to global epidemics of cardiovascular and metabolic diseases.

Prevention and treatment of pediatric obesity: an endocrine society clinical practice guideline based on expert opinion

OBJECTIVE

Our objective was to formulate practice guidelines for the treatment and prevention of pediatric obesity.

CONCLUSIONS

We recommend defining overweight as body mass index (BMI) in at least the 85th percentile but < the 95th percentile and obesity as BMI in at least the 95th percentile against routine endocrine studies unless the height velocity is attenuated or inappropriate for the family background or stage of puberty; referring patients to a geneticist if there is evidence of a genetic syndrome; evaluating for obesity-associated comorbidities in children with BMI in at least the 85th percentile; and prescribing and supporting intensive lifestyle (dietary, physical activity, and behavioral) modification as the prerequisite for any treatment. We suggest that pharmacotherapy (in combination with lifestyle modification) be considered in: 1) obese children only after failure of a formal program of intensive lifestyle modification; and 2) overweight children only if severe comorbidities persist despite intensive lifestyle modification, particularly in children with a strong family history of type 2 diabetes or premature cardiovascular disease. Pharmacotherapy should be provided only by clinicians who are experienced in the use of antiobesity agents and aware of the potential for adverse reactions. We suggest bariatric surgery for adolescents with BMI above 50 kg/m(2), or BMI above 40 kg/m(2) with severe comorbidities in whom lifestyle modifications and/or pharmacotherapy have failed. Candidates for surgery and their families must be psychologically stable and capable of adhering to lifestyle modifications. Access to experienced surgeons and sophisticated multidisciplinary teams who assess the benefits and risks of surgery is obligatory. We emphasize the prevention of obesity by recommending breast-feeding of infants for at least 6 months and advocating that schools provide for 60 min of moderate to vigorous daily exercise in all grades. We suggest that clinicians educate children and parents through anticipatory guidance about healthy dietary and activity habits, and we advocate for restricting the availability of unhealthy food choices in schools, policies to ban advertising unhealthy food choices to children, and community redesign to maximize opportunities for safe walking and bike riding to school, athletic activities, and neighborhood shopping.

Optimal cut-points for body mass index, waist circumference and waist-to-hip ratio using the Framingham coronary heart disease risk score in an Arab population of the Middle East

We aimed to determine the gender-specific optimal cut-points for body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) associated with risk of cardiovascular disease, using Framingham risk score and receiver-operating characteristic (ROC) analysis, among Omani Arabs. Nine percent of men, compared to 3% of women, had a 10-year total coronary heart disease (CHD) risk > or = 20%. In both genders, WHR was a better predictor of CHD (area under the ROC curve 0.771 for men and 0.802 for women), followed by WC (0.710 and 0.727) and BMI (0.601 and 0.639), respectively. For a 10-year CHD risk of > or = 20%, the optimal cut-points to assess adiposity in Omani men and women were > 22.6 and 22.9 kg/m2 for BMI, > 78.5 and 84.5 cm for WC, and > 0.96 and > 0.98 for WHR, respectively. To identify obesity among Omani Arabs, different cut-points for BMI, WC and WHR than the currently recommended ones are needed.

Comparison of diagnostic criteria of the metabolic syndrome in 3 ethnic groups of Canada

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities in which visceral obesity is a prominent feature. Although a matter of debate, the MetS essentially represents "at risk obesity." The purpose of this study was to compare the various definitions of MetS, with a special focus on abdominal obesity, and to explore sex and ethnic differences in the prevalence and nature of this syndrome in 3 ethnic groups residing in the Canadian province of Québec. The study population included adult participants of 3 cross-sectional health surveys conducted in southern Québec, James Bay, and Nunavik between 1990 and 1992. A total of 2613 adults (18-74 years old) were included: 1417 Quebecers, 817 Indian Crees, and 379 Inuit. The prevalence of MetS varied by definitions, and the highest agreement was observed between the National Cholesterol Education Program-Adult Treatment Panel III and the International Diabetes Federation (79%). Most women (25%), regardless of ethnic origin, presented with a "triad" profile characterized by high waist circumference, elevated triglycerides, and low high-density lipoprotein, whereas 20% of men had the "deadly quartet" of high blood pressure with the triad mentioned above. Furthermore, our results highlight an obvious difference in the impact of the increased abdominal obesity on metabolic parameters such as insulin resistance measured by the homeostasis model assessment according to ethnic origin (P < .001). These 3 unique population-based samples suggest that abdominal obesity does not have a similar deleterious impact according to ethnicity, suggesting the need for an ethnic-based MetS definition.

Association of CHRNA2 polymorphisms with overweight/obesity and clinical characteristics in a Korean population

BACKGROUND

Genes correlated with nicotine may be important in obesity because of the role of nicotine in food intake.

METHODS

To determine if single nucleotide polymorphisms (SNPs) in the neuronal nicotinic acetylcholine receptor alpha2 subunit gene (CHRNA2) are associated with overweight/obesity, 156 non-obese and 200 overweight/obese Koreans were genotyped for four CHRNA2 SNPs using an Affymetrix Array Chip.

RESULTS

Of four SNPs, only one, rs2043063, was associated with overweight/obesity in the study population (co-dominant, p=0.049; dominant, p=0.027). Associations between the significant SNP and obesity-related clinical characteristics were observed, but these were not significant.

CONCLUSIONS

The CHRNA2 rs2043063 SNP might be a risk factor for overweight/obesity in Koreans. Therefore, further studies are needed to investigate whether mutations or common polymorphisms of the CHRNA2 gene represent a risk factor for obesity.

Adipokines and the prediction of the accumulation of cardiovascular risk factors or the presence of metabolic syndrome in elementary school children

BACKGROUND

Information is limited about how adipokines predict the accumulation of cardiovascular (CV) risk factors or the presence of metabolic syndrome (MS) in children.

METHODS AND RESULTS

The subjects were 321 children (200 boys and 121 girls; 109 normal and 212 obese) aged 6-12 years. Obesity was defined as a body mass index of >or= the 95(th) percentile for age and sex. MS was defined by using the newly established Task Force criteria. The levels of the adipokines--adiponectin, leptin, ghrelin, high sensitive C-reactive protein (CRP) and resistin--were measured. Regression analyses revealed that high leptin levels were predictive of the accumulation of CV risk factors in normal weight, obese, and entire (normal weight and obese) group of subjects. High CRP in the normal weight group and low adiponectin in the obese and the entire groups were also independently predictive of the accumulation of risk factors. A high leptin level was solely predictive of the presence of MS in obese and entire groups.

CONCLUSIONS

Leptin was the most sensitive marker for predicting the accumulation of CV risk factors and the presence of MS in elementary school children. Primary prevention is important because both leptin and adiponectin levels abruptly worsened when children obtained any 1 risk factor.

Low-cost strategies to predict cardiovascular disease

In this commentary, we discuss the potential utility of low-cost screening algorithms for the prediction of risk for cardiovascular disease. Strategies such as these might enhance screening and prevention programs but require validation. Testing the usefulness of low-cost prediction models in developing regions is the next logical step in carrying this concept forward.

Dyslipidemia and glucose dysregulation in overweight and obese patients

Inactivity and a sedentary lifestyle contribute to overweight, obesity, and cardiometabolic risk. Overweight and obesity can lead to metabolic abnormalities, insulin resistance, type 2 diabetes mellitus (DM), lipid disorders, and cardiovascular disease. Diet and exercise can effectively reverse overweight and obesity and their related comorbidities. Modest weight loss (5%-10%) and modest physical activity (30 minutes a day) are first-line recommendations for the prevention of type 2 DM. Clinical trials have demonstrated that insulin sensitivity can be improved and type 2 DM can be prevented through lifestyle modification and pharmacologic therapy, including antiobesity drugs, antidiabetic drugs, statins, and antihypertensive drugs. The endocannabinoid system plays an important role in regulating metabolism through its effects on food intake at the level of the hypothalamus and on body composition through peripheral effects on adipose tissue.

Vascular risk factors in South Asians

South Asians originate from the Indian sub-continent (India, Pakistan, Bangladesh, Sri Lanka and Nepal) and represent one fifth of the world's population. Several studies suggested that South Asians have an increased risk of developing coronary heart disease (CHD) when compared with European populations. We review the role of traditional and emerging risk factors in the increased CHD risk in South Asians. The high prevalence of insulin resistance and type 2 diabetes mellitus in South Asians may be a major cause for their elevated vascular risk. However, other established and emerging risk factors are also overrepresented in South Asians. Large-scale prospective studies could determine the relative contribution of established and emerging vascular risk factors in South Asians. There is an urgent need for trials in South Asians that will evaluate clinical outcomes following treatment of these risk factors.

Population-based prevention of obesity: the need for comprehensive promotion of healthful eating, physical activity, and energy balance: a scientific statement from American Heart Association Council on Epidemiology and Prevention, Interdisciplinary Committee for Prevention (formerly the expert panel on population and prevention science)

Obesity is a major influence on the development and course of cardiovascular diseases and affects physical and social functioning and quality of life. The importance of effective interventions to reduce obesity and related health risks has increased in recent decades because the number of adults and children who are obese has reached epidemic proportions. To prevent the development of overweight and obesity throughout the life course, population-based strategies that improve social and physical environmental contexts for healthful eating and physical activity are essential. Population-based approaches to obesity prevention are complementary to clinical preventive strategies and also to treatment programs for those who are already obese. This American Heart Association scientific statement aims: 1) to raise awareness of the importance of undertaking population-based initiatives specifically geared to the prevention of excess weight gain in adults and children; 2) to describe considerations for undertaking obesity prevention overall and in key risk subgroups; 3) to differentiate environmental and policy approaches to obesity prevention from those used in clinical prevention and obesity treatment; 4) to identify potential targets of environmental and policy change using an ecological model that includes multiple layers of influences on eating and physical activity across multiple societal sectors; and 5) to highlight the spectrum of potentially relevant interventions and the nature of evidence needed to inform population-based approaches. The evidence-based experience for population-wide approaches to obesity prevention is highlighted.

Impact of body mass index on incident hypertension and diabetes in Chinese Asians, American Whites, and American Blacks: the People's Republic of China Study and the Atherosclerosis Risk in Communities Study

Researchers have hypothesized that the impact of body mass index on chronic disease may be greater in Asians than in Whites; however, most studies are cross-sectional and have no White comparison group. The authors compared the associations with body mass index in Chinese Asians (n = 5,980), American Whites (n = 10,776), and American Blacks (n = 3,582) using prospective data from the People's Republic of China Study (1983-1994) and the Atherosclerosis Risk in Communities Study (1987-1998). Slopes of risk differences over body mass index levels were compared among the three ethnic groups in adjusted analyses. The authors found larger associations with body mass index in Chinese Asians compared with American Whites and Blacks for hypertension (p < 0.05). The increase in the incidence of hypertension associated with a one-unit increase in body mass index over approximately 8 years of follow-up was 2.5, 1.7, and 1.8 percentage points for Chinese Asians, American Whites, and American Blacks, respectively. For diabetes, the estimates were 1.7, 1.1, and 1.6 percentage points for the same groups- higher in Chinese Asians than in American Whites (p < 0.05) but similar between Chinese Asians and American Blacks. Given the ethnic differences in associations, the results support advocacy of public health and medical actions toward obesity prevention and treatment in China.

Rise in childhood obesity with persistently high rates of undernutrition among urban school-aged Indo-Asian children

BACKGROUND

Childhood obesity is an emerging global public health challenge. Evidence for the transition in nutrition in Indo-Asian developing countries is lacking. We conducted these analyses to determine the trends in nutritional status of school-aged children in urban Pakistan.

METHODS

Data on the nutritional status of children aged 5 to 14 years from two independent population-based representative surveys, the urban component of the National Health Survey of Pakistan (NHSP; 1990-1994) and the Karachi survey (2004-2005), were analysed. Using normative data from children in the United States as the reference, trends for age- and gender-standardised prevalence (95% CI) of underweight (more than 2 SD below the weight-for-age reference), stunted (more than 2 SD below the height-for-age reference) and overweight and obese (body mass index (BMI) 85(th) percentile or greater) children were compared for the two surveys. The association between physical activity and being overweight or obese was analysed in the Karachi survey using logistical regression analysis.

RESULTS

2074 children were included in the urban NHSP and 1675 in the Karachi survey. The prevalence of underweight children was 29.7% versus 27.3% (p = 0.12), stunting was 16.7% versus 14.3% (p = 0.05), and prevalence of overweight and obese children was 3.0 versus 5.7 (p<0.001) in the NHSP and Karachi surveys, respectively. Physical activity was inversely correlated with being overweight or obese (odds ratio, 95% CI, 0.51, 0.32-0.80 for those who engaged in more than 30 minutes of physical activity versus those engaged in less than 30 minutes' activity).

CONCLUSIONS

Our study highlights the challenge faced by Pakistani school-aged children. There has been a rapid rise in the number of overweight and obese children despite a persistently high burden of undernutrition. Focus on prevention of obesity in children must include strategies for promoting physical activity.