Does using ethnic specific criteria improve the usefulness of the term metabolic syndrome? Controversies and suggestions

Association of body mass index and abdominal adiposity with atherogenic lipid profile in Nigerians with type 2 diabetes and/or hypertension

Background:

We explored the relationship between anthropometric indices (obesity and abdominal adiposity) and the presence of an atherogenic lipid profile in Nigerians with major cardiovascular risk factors (type 2 diabetes mellitus-T2DM, hypertension-HBP, and concomitant disease).

Materials and Methods:

Using a prospective design, 278 patients with T2DM, HBP, or concomitant disease, attending out-patient diabetes and hypertension clinics at a tertiary institution in Nigeria were evaluated. All patients were cholesterol-lowering oral medication naοve. Demographic and clinical data and anthropometric measurements were documented. Fasting lipid profiles were measured in all cases. The cut-off points for defining dyslipidaemia were: Elevated total cholesterol (TC) (mg/dL) ≥200, elevated low-density lipoprotein cholestrol (LDL-C) (mg/dL) ≥100, low high-density lipoprotein cholesterol (HDL-C) (mg/dL) <40 for men and <50 for women, and high triglycerides (TG) (mg/dL) ≥150 mg/dL.

Results:

We found a significantly higher mean BMI (kg/m²) in the HBP group (30.5 ± 6.0) compared to T2DM (28.1 ± 5.9) and concomitant HBP and T2DM groups (29.4 ± 5.2) (ANOVA; P = 0.02). The most frequent dyslipidaemia was elevated LDL-C in 92 (96.8%) HBP, 73 (85.9%) T2DM and 79 (80.6%) concomitant disease. The frequency of low HDL-C was highest in T2DM (68.2%) compared to the other 2 groups (P = 0.03).

Conclusions:

Only TG levels were found to relate with any anthropometric index (waist circumference (WC) in this case) in Nigerians with major cardiovascular risk factors in this study. Routine anthropometric indices do not appear to be reliable surrogates for atherogenicity measured by abnormalities in TC, LDL-C and HDL-C.

Cutoff point of waist circumference for the diagnosis of metabolic syndrome in an Iranian population

SUMMARY

BACKGROUND

Proposed cutoffs for waist circumference (WC) in western populations may be not appropriate for Asian populations. The published data among Iranians are insufficient to address this issue. This study was designed to identify cutoffs for WC that confer increased risk of metabolic syndrome in Iranian adults living in Zanjan, a province located in the west of Tehran.

MATERIALS AND METHODS

Data of a cross-sectional sample of 3277 Iranian adults aged more than 20 years were analyzed. In the original study individual body weight, height, WC, and blood pressure were assessed and fasting plasma glucose, triglycerides, total cholesterol, low- and high-density lipoprotein cholesterol were measured. After excluding WC, existence of two or more of the remaining four risk factors of the modified NCEP III criteria for metabolic syndrome were defined as multiple risk factors. Receiver operating characteristic (ROC) analysis was used to find out the optimal cutoff values of WC to predict metabolic syndrome.

RESULTS

The cutoff level yielding the maximal sensitivity and specificity for predicting the presence of metabolic syndrome (multiple risk factors) was 87 cm in men and 82 cm in women. Cutoffs corresponding to body mass index (BMI) 25 and 30 kg/m(2) to predict metabolic syndrome were 84 and 97 cm in men and 78 and 91 cm in women, respectively.

CONCLUSIONS

Lower cutoffs for WC should be considered in the identification of Iranian population at high risk of metabolic syndrome.

Patients with uncontrolled components of metabolic syndrome have increased risk of complications following total joint arthroplasty

Metabolic syndrome (MetS)-a diagnostic grouping of diabetes, dyslipidemia, hypertension, and obesity-has been indicated as a risk factor for perioperative complications following total joint arthroplasty (TJA). This study investigates the impact of MetS on perioperative complications, specifically the importance of controlling MetS components. One hundred thirty-three patients undergoing TJA with all four components of MetS were identified. They were matched one-to-one with patients without MetS. Control of diabetes, dyslipidemia, and hypertension was assessed. Thirty-five patients with MetS were found to have at least a single uncontrolled component. The complication rates were 49%, 8%, and 8% for uncontrolled MetS, controlled MetS, and no MetS, respectively. Multivariate analysis confirmed independent associations between control of MetS components and both perioperative complications and length of stay. Both surgeons and patients should be aware of the substantial risk of dangerous complications following TJA in patients with uncontrolled metabolic syndrome.

Primary care physician's knowledge of ethnicity-specific guidelines for obesity diagnosis and readiness for obesity intervention among South Asian Indians

Many primary care physicians lack sufficient knowledge on current guidelines for overweight/obesity diagnosis among minority groups. We assessed physician knowledge and awareness on modified guidelines for identifying obesity among South Asian Indians (SAIs). Cross sectional survey of 183 physicians practicing in Houston, who reported on their knowledge on guidelines for obesity among SAIs, frequency of measurement of surrogate markers, self-reported competency in management of obesity, and readiness to seek training on obesity diagnosis among SAIs. 65% of physicians agree obesity is a growing problem among SAIs with only 9% of physicians reporting measuring waist circumference. Only 21% of physicians were aware of the recommended WHO modified BMI criteria and 41% the IDF criteria for waist circumference. SAI physicians had significantly higher knowledge compared to other physicians. 78% were ready to seek training on the modified guidelines across ethnicity and training. There is a low level of knowledge on ethnicity-specific guidelines for obesity diagnosis among physicians. There is however a readiness to learn, indicating the need for a physician awareness-training on current obesity guidelines, for various ethnic populations.

Do the prevalence and components of metabolic syndrome differ among different ethnic groups? A cross-sectional study among obese Malaysian adolescents

OBJECTIVE

The aim of this study was to determine the prevalence of metabolic syndrome and the most common combination of cardiometabolic disorders among different ethnic groups of obese adolescents in Malaysia.

RESEARCH DESIGN AND METHODS

A cross-sectional study among 335 obese adolescent boys and girls aged 12-18 years from 10 randomly selected schools was conducted. After recording blood pressure and waist circumference (WC), a fasting blood sample was obtained and analyzed for glucose and lipids. Metabolic syndrome was diagnosed on the basis of adolescent metabolic syndrome criteria specified by National Cholesterol Education Program Adult Treatment Panel III if three of the five risk factors--hypertriglyceridemia, hyperglycemia, hypertension, low high-density lipoprotein C, and increased WC--were present. The prevalence among different ethnic groups was analyzed.

RESULTS

The obesity rate among adolescents was 8.4%, and nearly one-third of the obese adolescents had metabolic syndrome. More than 90% of obese adolescents had at least one metabolic abnormality. Metabolic syndrome was more prevalent among obese boys (40.2%) compared to obese girls (17%). Boys had significantly higher mean WC and triglycerides and lower HDL-C (P value 0.0001). Increased WC and triglycerides and high blood pressure comprised the most prevalent (34.3%) risk factor combination followed by WC, low HDL, and high blood pressure (22.5%). Over all, Indians had the highest prevalence of metabolic syndrome (36.4%), followed by Chinese (33.8%) and Malays (27.4%). Elevated triglyceride levels were more prevalent among Chinese, hypertension among Malays, and the other three abnormalities among Indians.

CONCLUSION

Indians had the highest prevalence of metabolic syndrome. Increased WC and triglycerides and high blood pressure comprised the most prevalent risk factor combination.

Comparison of BMI and anthropometric measures among South Asian Indians using standard and modified criteria

OBJECTIVE

To compare the prevalence rates of obesity based on BMI/anthropometric measures, using WHO standard and ethnicity-specific criteria, the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) and the International Diabetes Federation (IDF) definitions, among a migrant South Asian Indian population.

DESIGN

Cross-sectional study conducted in October 2007.

SUBJECTS

A total of 213 participants of South Asian descent over the age of 18 years. Measures included a questionnaire with basic demographic information and self-reported histories of diabetes, coronary artery disease and/or hypercholesterolaemia. Height, weight, waist and hip circumference and blood pressure measurements were obtained.

SETTING

Houston and surrounding suburbs.

RESULTS

WHO-modified (WHO-mod) BMI and IDF waist circumference (WC) criteria independently identified higher numbers of overweight/obese participants; however, when the WHO-mod BMI or IDF WC criteria were applied, nearly 75% of participants were categorized as overweight/obese--a proven risk factor for the future development of metabolic syndrome.

CONCLUSIONS

Obesity is likely under-diagnosed using the standard WHO and NCEP-ATPIII guidelines. Stressing the use of modified criteria more universally to classify obesity among South Asian Indians may be optimal to identify obesity and help appropriately risk stratify for intervention to prevent chronic diseases.

Racial/ethnic differences in the association of triglycerides with other metabolic syndrome components: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

The aim of this study was to examine whether there are ethnic differences in the association of triglycerides (TG) with waist circumference (WC), blood pressure, high-density lipoprotein cholesterol (HDL-C), fasting glucose, and insulin resistance and to examine the disparities in the prevalence of the metabolic syndrome components between African Americans and non-Hispanic whites who do not have hypertriglyceridemia.

METHODS

This study used the baseline data from the Multi-Ethnic Study of Atherosclerosis (MESA) study. The analysis included non-Hispanic whites (N = 2,427) and African Americans (N = 1,519) aged 45-84 years free of clinically evident cardiovascular disease and diabetes at baseline. The revised National Cholesterol Education Program (NCEP) criteria were used to define the metabolic syndrome and its components.

RESULTS

African Americans had lower prevalence of elevated TG as compared with non-Hispanic whites. The association of TG with other components of the metabolic syndrome appeared to be similar between African Americans and non-Hispanic whites except for one. There was significant association of TG with WC among white women but not among African American women after adjusting for demographic and other variables (P for interaction of TG with ethnicity <0.001). In participants with TG < 150 mg/dL, African American women had higher prevalence rates than white women of abdominal obesity, elevated blood pressure, low HDL-C, elevated fasting glucose and homeostasis model assessment of insulin resistance (HOMA-IR). In men, the prevalence rates of high blood pressure, elevated fasting glucose, and HOMA-IR were significantly higher in African Americans than in whites.

CONCLUSIONS

The study findings suggest that further evaluation is warranted regarding the cutoffs for elevated TG and its clustering effect with other cardiometabolic risk factors on predicting risk for diabetes and cardiovascular disease (CVD) in African Americans.

Factors alleviating metabolic syndrome via diet-induced weight loss with or without exercise in overweight Japanese women

OBJECTIVE

Although a 5%-10% loss in the baseline weight has been associated with improvement in obesity-related disorders, only a few studies have explored the factors to alleviate metabolic syndrome (MS). This study aimed to determine the factors that alter MS components in overweight Japanese women.

METHODS

Between 1999 and 2006, 323 Japanese women aged 24-67 with body mass indices of 25-40 kg/m(2) and the presence of at least 1 component of MS were recruited from Ibaraki and Chiba. The participants were enrolled in a 3-month weight-loss program with a low-calorie diet with or without exercise. The factors to alleviate MS components were explored using classification and regression tree (CART) analyses.

RESULTS

Of the 323 participants, 309 completed the weight-loss program and were included in the analyses. The CART analyses revealed that a weight reduction of 8.1% in baseline body weight was sufficient to improve at least 1 component of MS. Similarly, classification trees were generated for improvement in abdominal obesity (essential factor: > or =13.0% weight loss), hypertension (essential factor: baseline age, < or =41.5 years), and hyperglycemia (essential factor: > or =13.2% weight loss).

CONCLUSION

These results suggest that moderate weight loss of 8%-13% contributes to improving the MS components in overweight Japanese women.

Ethnic differences in cardiometabolic risk profile in an overweight/obese paediatric cohort in the Netherlands: a cross-sectional study

Background

Differences in prevalence of cardiometabolic risk factors between different ethnic groups are largely unknown. We determined the variation in cardiometabolic risk profile according to ethnicity in a cohort overweight/obese Dutch children.

Methods

An oral glucose tolerance test was performed in 516 overweight/obese Dutch children of multi-ethnic origin, attending an obesity out-patient clinic of an urban general hospital (mean age 10.6 ± 3.2; 55.2% boys). Anthropometric parameters and blood samples were collected, and the prevalence of (components of) the metabolic syndrome (MetS) and insulin resistance were determined in each ethnic group.

Results

Major ethnic groups were Dutch native (18.4%), Turkish (28.1%), and Moroccan (25.8%). The remaining group (27.7%) consisted of children with other ethnicities. Turkish children had the highest mean standardized BMI compared to Dutch native children (P < 0.05). As compared to Moroccan children, they had a higher prevalence of MetS (22.8% vs. 12.8%), low HDL-cholesterol (37.9% vs. 25.8%), hypertension (29.7% vs. 18.0%) and insulin resistance (54.9% vs. 37.4%, all P < 0.05). Although Turkish children also had higher prevalences of forementioned risk factors than Dutch native children, these differences were not statistically significant. Insulin resistance was associated with MetS in the Turkish and Moroccan subgroup (OR 6.6; 95%CI, 2.4–18.3 and OR 7.0; 95%CI, 2.1–23.1, respectively).

Conclusion

In a Dutch cohort of overweight/obese children, Turkish children showed significantly higher prevalences of cardiometabolic risk factors relative to their peers of Moroccan descent. The prospective value of these findings needs to be established as this may warrant the need for differential ethnic-specific preventive measures.

First reference curves of waist circumference for German children in comparison to international values: the PEP Family Heart Study

BACKGROUND

Waist circumference (WC) is a sensitive marker for abdominal obesity in the pediatric age group. However, WC is influenced by age, sex, ethnicity and body mass index (BMI), causing difficulties in the selection of the most appropriate cut-off value. Considering the lack of reference values in Germany, we developed age- and gender-specific WC smoothed reference curves in German children, and compared them with reference curves obtained from different countries.

METHODS

A representative sample of 3531 German children (1788 boys, 1743 girls) aged 3-11 years participating in the Prevention Education Program (PEP) Family Heart Study was studied. WC was measured according to the recommendations of the World Health Organization, then age- and sex-specific WC reference curves were constructed and smoothed using the LMS method and SPSS 14.0 for statistical analysis.

RESULTS

WC increased with age in both boys and girls. Boys had higher values of WC than girls at every age and percentile level. 4.1% of the boys and 2.8% of the girls had WC values >97th percentile as compared to 6.3% of the boys and 4.9% of the girls with >97th percentile of BMI (severe obesity). 3.1% of the boys and 2% of the girls had both risk factors. Because 85.3% of the boys and 87.3% of the girls with WC<90th percentile had normal weight, this cut-off point might be appropriate for defining high WC.

CONCLUSIONS

These first WC reference curves of German children can be added to the existing international curves for children; comparison of different populations demonstrated that the German values are in the middle range of the curves obtained in different countries. Our findings about significant differences between the reference curves obtained in various regions emphasize the necessity of developing population-specific percentiles, and to use them in clinical and epidemiological studies among children.