Optimal cut-off values for obesity: using simple anthropometric indices to predict cardiovascular risk factors in Taiwan

Waist-to-height ratio, an optimal predictor for obesity and metabolic syndrome in Chinese adults

OBJECTIVE

Anthropometric indices to obesity were evaluated as predictors of metabolic syndrome risk factors. Our purpose was to explore an optimal or more reliable anthropometric indicator and optimal cut-off points for obesity on metabolic syndrome in Chinese adults.

PARTICIPANTS AND METHODS

The survey was conducted involving 2947 participants, aged 20 or above with cross-sectional study of population. The predictive validity and optimal cut-off values were analyzed by receiver operating characteristic (ROC) curves, area under curve (AUC) and the largest Youden's index (sensitivity + specificity - 1) by gender group, respectively. Kappa value showed diagnostic consistency.

RESULTS

According to the criteria of CDS 2004, IDF 2005 and AHA/NHLBI 2005, the prevalence of metabolic syndrome was 10.32%, 9.64% and 16.12% respectively, which indicated that the prevalence was higher in men than in women and increased with age (P < 0.05). The BMI, WC, WHR and WHtR in metabolic syndrome patients were greater than those in healthy volunteers and the indices in men were higher than those in women. With adjusted age and gender, the partial correlation coefficient for BMI-WC, BMI-WHR and BMI-WHtR was 0.7991, 0.5278 and 0.8196, respectively (P < 0.05). The area under curves (AUCs) of receiver operating characteristic (ROC) curves for WHtR was larger (P < 0.05) than that for WC and WHR. The cut-point of WHtR was approximately 0.5 in both genders with a satisfactory balance between sensitivity and specificity, where the Kappa (k) value for WHtR-BMI was higher than that for WHtR-WHR, and WHtR-WC.

CONCLUSIONS

The results indicated that WHtR might be an optimal anthropometric predictor of metabolic syndrome risk factors and the cut-point of WHtR was approximately 0.50 in both genders of Chinese adults.

Cut-points for waist circumference in Europids and South Asians

There is little strong evidence that currently recommended higher waist circumference cut-points for Europids compared with South Asians are associated with similar risk for type 2 diabetes. This study was designed to provide such evidence. Longitudinal studies over 5 years were conducted among 5,515 Europid and 2,214 ethnically South Asian participants. Age-standardized diabetes incidence at different levels of waist circumference and incidence difference relative to a reference value were calculated. The Youden Index was used to determine waist circumference cut-points. At currently recommended cut-points, estimated annual diabetes incidence for a 50-year-old Europid was <0.6% for both sexes, and for a 50-year-old South Asian, 5.8% for men and 2.1% for women. Annual diabetes incidence of 1% was observed for a 50 year old at a waist circumference 35-40 cm greater in Europid compared to South Asian men and women. Incidence difference between recommended cut-points and a reference value (80 cm in men, 70 cm in women) was 0.3 and 4.4% per year for Europid and South Asian men, and 0.2 and 0.8% per year for Europid and South Asian women, respectively. Waist circumference cut-points chosen using the Youden Index were shown to be dependent on obesity levels in the population. The much higher observed risk of diabetes in South Asians compared to Europids at the respective recommended waist circumference cut-points suggests that differences between them should be greater. Approaches that use the Youden Index to select waist circumference cut-points are inappropriate and should not be used for this purpose.

A systematic review of waist-to-height ratio as a screening tool for the prediction of cardiovascular disease and diabetes: 0·5 could be a suitable global boundary value

This systematic review collated seventy-eight studies exploring waist-to-height ratio (WHtR) and waist circumference (WC) or BMI as predictors of diabetes and CVD, published in English between 1950 and 2008. Twenty-two prospective analyses showed that WHtR and WC were significant predictors of these cardiometabolic outcomes more often than BMI, with similar OR, sometimes being significant predictors after adjustment for BMI. Observations from cross-sectional analyses, forty-four in adults, thirteen in children, supported these predictions. Receiver operator characteristic (ROC) analysis revealed mean area under ROC (AUROC) values of 0·704, 0·693 and 0·671 for WHtR, WC and BMI, respectively. Mean boundary values for WHtR, covering all cardiometabolic outcomes, from studies in fourteen different countries and including Caucasian, Asian and Central American subjects, were 0·50 for men and 0·50 for women. WHtR and WC are therefore similar predictors of diabetes and CVD, both being stronger than, and independent of, BMI. To make firmer statistical comparison, a meta-analysis is required. The AUROC analyses indicate that WHtR may be a more useful global clinical screening tool than WC, with a weighted mean boundary value of 0·5, supporting the simple public health message 'keep your waist circumference to less than half your height'.

Optimal cutoff values of waist circumference and the discriminatory performance of other anthropometric indices to detect the clustering of cardiovascular risk factors for metabolic syndrome in Japanese men and women

OBJECTIVE

To evaluate the pertinent cutoffs of waist circumference (WC) and the discriminatory performance of other anthropometric indices to detect clustering cardiovascular risk factors for metabolic syndrome (MetS) in Japan, where the current WC cutoffs for MetS (85 cm for men and 90 cm for women) remain controversial.

METHODS

We analyzed the baseline data from 844 subjects (330 men and 514 women) aged 40-69 years who participated in a cohort study in Saga city, Japan, between November 2005 and December 2007. Receiver operating characteristic (ROC) analyses were performed to find an appropriate cutoff (defined as the point nearest to the upper left corner of the ROC curve) of each anthropometric index for the presence of multiple risk factors among dyslipidemia, hypertension, and hyperglycemia [which was defined as hemoglobin A1c (HbA1c) levels at and above 5.2, 5.5, or 5.8%, values approximately corresponding to fasting plasma glucose levels of 100, 110, and 120 mg/dL, respectively].

RESULTS

The optimal WC cutoff was 88 cm (sensitivity 60%, specificity 70%) for men and 82 cm (sensitivity 78%, specificity 62%) for women; changing the HbA1c cutoff affected the results in women only (~85 cm). For the currently defined WC cutoffs in Japan, specificity was low (53-57%) in men, whereas sensitivity was very low (32-42%) in women. Body mass index, proportion of body fat, waist-to-height ratio, and waist-to-hip ratio showed area under the curve values similar to that of WC.

CONCLUSION

The current Japanese criteria of WC for MetS may be low for men and too high and insensitive for women in our study population. Other anthropometric indices such as waist-to-height ratio did not confer an improved discriminatory performance compared with WC.

Optimal cut-off values and population means of waist circumference in different populations

Abdominal obesity is a risk factor for cardiometabolic disease, and has become a major public health problem in the world. Waist circumference is generally used as a simple surrogate marker to define abdominal obesity for population screening. An increasing number of publications solely rely on the method that maximises sensitivity and specificity to define ‘optimal’ cut-off values. It is well documented that the optimal cut-off values of waist circumference vary across different ethnicities. However, it is not clear if the variation in cut-off values is a true biological phenomenon or an artifact of the method for identifying optimal cut-off points. The objective of the present review was to assess the relationship between optimal cut-offs and population waist circumference levels. Among sixty-one research papers, optimal cut-off values ranged from 65·5 to 101·2 cm for women and 72·5 to 103·0 cm for men. Reported optimal cut-off values were highly correlated with population means (correlation coefficient: 0·91 for men and 0·93 for women). Such a strong association was independent of waist circumference measurement techniques or the health outcomes (dyslipidaemia, hypertension or hyperglycaemia), and existed in some homogeneous populations such as the Chinese and Japanese. Our findings raised some concerns about applying the sensitivity and specificity approach to determine cut-off values. Further research is needed to understand whether the differences among populations in waist circumference were genetically or environmentally determined, and to understand whether using region-specific cut-off points can identify individuals with the same absolute risk levels of metabolic and cardiovascular outcomes among different populations.

Cereal consumption and indicators of cardiovascular risk in adolescent girls

OBJECTIVE

To examine the association between cereal consumption and cardiovascular risk factors including waist, height, total cholesterol, LDL cholesterol and HDL cholesterol in a sample of adolescent girls.

DESIGN

Longitudinal study.

SETTING

The study was conducted from 1987 to 1997 and data were collected at three study sites (University of California at Berkeley, University of Cincinnati and Westat Inc., Rockville, MD, USA). Mixed models were used to estimate the association between the number of days of eating cereal and these four outcome variables.

SUBJECTS

Girls (n 2371) who participated in the 10-year National Heart, Lung, and Blood Growth and Health Study (NGHS) and completed a 3 d food diary in years 1-5 and 7, 8 and 10.

RESULTS

Adolescent girls who ate cereal more often had lower waist-to-height ratio (P<0.005), lower total cholesterol (P<0.05) and lower LDL cholesterol (P<0.05), taking into account sociodemographic variables, physical activity levels and total energy intake.

CONCLUSIONS

Findings suggest that cereal consumption is associated with markers of cardiovascular risk and that childhood patterns of consumption may influence the development of risk factors later in adolescence.

Dichotomization: 2 x 2 (x2 x 2 x 2...) categories: infinite possibilities

BACKGROUND

Consumers of epidemiology may prefer to have one measure of risk arising from analysis of a 2-by-2 table. However, reporting a single measure of association, such as one odds ratio (OR) and 95% confidence interval, from a continuous exposure variable that was dichotomized withholds much potentially useful information. Results of this type of analysis are often reported for one such dichotomization, as if no other cutoffs were investigated or even possible.

METHODS

This analysis demonstrates the effect of using different theory and data driven cutoffs on the relationship between body mass index and high cholesterol using National Health and Nutrition Examination Survey data. The recommended analytic approach, presentation of a graph of ORs for a range of cutoffs, is the focus of most of the results and discussion.

RESULTS

These cutoff variations resulted in ORs between 1.1 and 1.9. This allows investigators to select a result that either strongly supports or provides negligible support for an association; a choice that is invisible to readers. The OR curve presents readers with more information about the exposure disease relationship than a single OR and 95% confidence interval.

CONCLUSION

As well as offering results for additional cutoffs that may be of interest to readers, the OR curve provides an indication of whether the study focuses on a reasonable representation of the data or outlier results. It offers more information about trends in the association as the cutoff changes and the implications of random fluctuations than a single OR and 95% confidence interval.

Urgency of reassessment of role of obesity indices for metabolic risks

The definition of metabolic syndrome places emphasis on health care for persons at risk. However, whether an obesity index should be a mandatory component of the definition and whether obesity indices can identify metabolic risks satisfactorily require further exploration. Therefore, we investigated the effectiveness of various anthropometric obesity indices in identifying the clustering of 2 or more American Heart Association (AHA)/National Heart, Lung, and Blood Institute (NHLBI)/International Diabetes Federation (IDF)-defined metabolic risk factors (hypertension, hyperglycemia, hypertriglyceridemia, and low high-density lipoprotein cholesterol) for metabolic syndrome and those of other metabolic risk factors (high low-density lipoprotein cholesterol, hyperuricemia, high gamma-glutamyltransferase, fatty liver) in 6141 men and 2137 women. The anthropometric indices were the following: (1) for both sexes--various levels of waist-to-height ratio (WHtR) including 0.5 and body mass index (BMI) of 23 and 25 kg/m(2); (2) for men and women individually--waist circumference (W) 90/80 cm (AHA/NHLBI/IDF for ethnic groups), W 85/90 cm (Japan Society for the Study of Obesity), and combined W and BMI: W 85/90 cm and/or BMI 25 kg/m(2) (Japanese government). The results showed the following: (1) The optimal value for WHtR was 0.5 for AHA/NHLBI/IDF-defined risk factors and approximately 0.5 for other risk factors in both sexes. (2) The sensitivities of various proposed obesity indices for identifying clustering of defined and other risk factors varied between 74.4% (WHtR 0.5) and 36.3% (BMI 25) and between 80.5% (WHtR 0.5) and 43.7% (BMI 25) in men, and varied between 65.6% (WHtR 0.5) and 16.8% (W 90 cm) and between 82.3% (WHtR 0.5) and 28.2% (W 90 cm) in women. Because the sensitivities of many anthropometric indices were very low, a reassessment of the effectiveness of obesity indices in evaluating metabolic risks and especially their suitability as a single mandatory component of metabolic syndrome is urgently needed. However, WHtR 0.5 provides a very useful algorithm for screening persons at risk.

Risk factors on the menstrual cycle of healthy Taiwanese college nursing students

BACKGROUND

The purpose of this study was to explore risk factors, including age at menarche, body mass index (BMI), psychiatric stress and physical exercise on the menstrual cycle of healthy Taiwanese college nursing students.

METHODS

We conducted a cross-sectional survey involving 1300 female college students in the nursing curriculum between December 2002 and March 2003. We provided a structured questionnaire for each student. Information on the women's demographics, lifestyles and reproductive history related to menstrual cycle characteristics was requested. A total of 1095 healthy students were included in the analysis. A logistic regression was used to estimate the odds ratios for each of the menstrual cycle characteristics.

RESULTS

We found that age at menarche, BMI and psychiatric stress were associated with menstrual cycle characteristics in healthy college nursing students. In addition to menarche at the age of 14 years or later, obesity and psychological stress, menarche before 12 years of age was an important risk factor for menstrual dysfunction. Moreover, obese students had the highest risk of having a longer cycle and cycle irregularity.

CONCLUSIONS

Early menarche might be related to menstrual dysfunction in addition to late menarche, obesity and psychological stress. Moreover, obese students are at the highest risks for longer cycles and cycle irregularity.

Relations of pulse wave velocity to waist circumference independent of hip circumference

OBJECTIVES

Little is known about the effect of waist circumference (WC) on brachial artery pulse wave velocity (baPWV) independent of hip circumference (HC). Therefore, this study aimed to dissociate specific effect of WC on baPWV independent of HC.

METHODS

Of 1,053 rural residents (2004-2005), 777 subjects with no known history of coronary artery diseases or diabetes mellitus over 40 yr were included. To reduce collinearity, we assessed the independent effect of WC with HC on PWV by residual method (WC [RM]).

RESULTS

In women, most correlation coefficients were significant between measures of abdominal obesity and baPWV, with the highest (0.32) in waist to hip ratio (WHR), whereas no significance was found in men. All mean values of baPWV among the abdominally obese were higher than those of normal group in women, which were in the order of WHR, WC (RM), and WC. Adjusted OR with 95% CI for baPWV was significantly elevated by increase of WC (RM) upto 4.8 (95% CI: 2.1-11.2), and as 4.3 by WHR (95% CI: 1.6-11.4).

CONCLUSION

Considering the difficulty in biologically interpreting WHR, WC (RM) may be a useful indicator of abdominal obesity among females in that it reflects the risk of pulse wave velocity.

Clustering of other metabolic risk factors in subjects with metabolic syndrome

Various anthropometric indices have been proposed for metabolic syndrome. We investigated the clustering of metabolic risk factors other than components of metabolic syndrome and physical activity in subjects with and without metabolic syndrome as defined by different anthropometric indices. The subjects comprised 6141 men and 2137 women who underwent routine health examinations in Tokyo. We compared metabolic risk factors (high low-density lipoprotein cholesterol, hyperuricemia, high gamma-glutamyltransferase, fatty liver) and sedentary history in subjects with and without metabolic syndrome as defined by the American Heart Association by substituting various proposed anthropometric indices of abdominal obesity (waist circumference >or=85, >or=90, or >or=102 cm for men and >or=90, >or=80, or >or=88 cm for women; waist-to-height ratio >or=0.5 for both men and women). Irrespective of the anthropometric index or sex, the age-adjusted odds ratios for risk factors and sedentary history were all significantly greater in subjects with metabolic syndrome (men and women: 1.26 approximately 1.35 and 2.06 approximately 2.63 for high low-density lipoprotein cholesterol, 2.36 approximately 2.60 and 3.88 approximately 7.20 for hyperuricemia, 2.54 approximately 3.02 and 2.92 approximately 4.05 for high gamma-glutamyltransferase, 4.42 approximately 4.87 and 9.43 approximately 12.27 for fatty liver, and 1.37 approximately 1.50 and 1.43 approximately 1.72 for sedentary history). Findings still persisted in those not receiving medication for diabetes mellitus or coronary heart disease. Therefore, attention should be paid to other metabolic risk factors in subjects with metabolic syndrome, irrespective of the anthropometric index or sex. Further study is also needed to clarify the most appropriate definition of metabolic syndrome so as to include the spectrum of risk factors that best represents the future risk of cardiovascular and other diseases.

The discrimination of dyslipidaemia using anthropometric measures in ethnically diverse populations of the Asia-Pacific Region: the Obesity in Asia Collaboration

Dyslipidaemia is a major risk factor for cardiovascular disease and is only detectable through blood testing, which may not be feasible in resource-poor settings. As dyslipidaemia is commonly associated with excess weight, it may be possible to identify individuals with adverse lipid profiles using simple anthropometric measures. A total of 222 975 individuals from 18 studies were included as part of the Obesity in Asia Collaboration. Linear and logistic regression models were used to assess the association between measures of body size and dyslipidaemia. Body mass index, waist circumference, waist : hip ratio (WHR) and waist : height ratio were continuously associated with the lipid variables studied, but the relationships were consistently stronger for triglycerides and high-density lipoprotein cholesterol. The associations were similar between Asians and non-Asians, and no single anthropometric measure was superior at discriminating those individuals at increased risk of dyslipidaemia. WHR cut-points of 0.8 in women and 0.9 in men were applicable across both Asians and non-Asians for the discrimination of individuals with any form of dyslipidaemia. Measurement of central obesity may help to identify those individuals at increased risk of dyslipidaemia. WHR cut-points of 0.8 for women and 0.9 for men are optimal for discriminating those individuals likely to have adverse lipid profiles and in need of further clinical assessment.

Optimal anthropometric factor cutoffs for hyperglycemia, hypertension and dyslipidemia for the Taiwanese population

BACKGROUND

Optimal cutoffs for obesity indices are rarely studied in Asians. We evaluated these cutoffs for diabetes, hypertension, dyslipidemia and any risk factor for the Taiwanese general population.

METHODS

Body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), waist-height ratio (WHeiR) and other data for 4683 (2280 men and 2403 women) participants of the population-based Taiwanese Survey on Hypertension, Hyperglycemia and Hyperlipidemia were used. Areas under curves (AUCs) were analyzed and optimal cutoffs were estimated by maximizing the sums of sensitivity and specificity. Potential confounders included age, smoking, alcohol, betel nut chewing and exercise.

RESULTS

Optimal cutoffs for men and women, respectively, were 23.7-26.3 and 22.1-23.2 kg/m2 for BMI; 85.0-87.0 and 74.0-83.0 cm for WC; 0.87-0.90 and 0.78-0.83 for WHR; and 0.48-0.52 and 0.48-0.52 for WHeiR. AUCs were not significantly different among the indices for diabetes in men and for hypertension in women. In men, WHR was significantly inferior to the other indices for predicting hypertension, dyslipidemia and any risk factor. In women, BMI was significantly inferior to the others for diabetes. For dyslipidemia and any risk factor in women, WHeiR showed the largest AUCs and significant differences were seen in the following pairs: WHeiR vs. BMI and WHeiR vs. WHR for dyslipidemia and WC vs. WHR and WHeiR vs. WHR for any risk factor.

CONCLUSIONS

WC and WHeiR have similar efficacy and are superior to BMI and WHR. However, WHeiR has the extra benefit of a unisex cutoff within a narrow range.

Optimal waist:height ratio cut-off point for cardiometabolic risk factors in Turkish adults

Objective

To identify the optimal waist:height ratio (WHtR) cut-off point that discriminates cardiometabolic risk factors in Turkish adults.

Design

Cross-sectional study. Hypertension, dyslipidaemia, diabetes, metabolic syndrome score ≥2 (presence of two or more metabolic syndrome components except for waist circumference) and at least one risk factor (diabetes, hypertension or dyslipidaemia) were categorical outcome variables. Receiver-operating characteristic (ROC) curves were prepared by plotting 1 − specificity on the x-axis and sensitivity on the y-axis. The WHtR value that had the highest Youden index was selected as the optimal cut-off point for each cardiometabolic risk factor (Youden index = sensitivity + specificity − 1).

Setting

Turkey, 2003.

Subjects

Adults (1121 women and 571 men) aged 18 years and over were examined.

Results

Analysis of ROC coordinate tables showed that the optimal cut-off value ranged between 0·55 and 0·60 and was almost equal between men and women. The sensitivities of the identified cut-offs were between 0·63 and 0·81, the specificities were between 0·42 and 0·71 and the accuracies were between 0·65 and 0·73, for men and women. The cut-off point of 0·59 was the most frequently identified value for discrimination of the studied cardiometabolic risk factors. Subjects classified as having WHtR ≥ 0·59 had significantly higher age and sociodemographic multivariable-adjusted odds ratios for cardiometabolic risk factors than subjects with WHtR < 0·59, except for diabetes in men.

Conclusions

We show that the optimal WHtR cut-off point to discriminate cardiometabolic risk factors is 0·59 in Turkish adults.

Prediction of hypertension by different anthropometric indices in adults: the change in estimate approach

OBJECTIVE

To examine the relative contribution for the prediction of hypertension by waist circumference (WC), waist:stature ratio (WSR) or waist:hip ratio (WHR) with that by BMI, to ascertain if WC, WSR or WHR enhances the prediction of hypertension by BMI.

DESIGN

Population-based, cross-sectional study. A change of >or=10 % in the prevalence ratio of BMI (PR) or the area under the receiver-operating characteristic curve (AUC) when WC, WSR or WHR was added to a model with BMI was used as the criterion for significant contribution to the prediction of hypertension by BMI. For greater contributions (>or=10 %) these waist measures were considered as better predictors.

SETTING

Nine provinces in China.

SUBJECTS

Chinese adults aged 18 to 65 years (n 7336) who participated in the 2004 China Health and Nutrition Survey.

RESULTS

The prevalence of hypertension (17 % and 23 % for women and men, respectively) was significantly related to increased BMI, WC, WSR and WHR (P for trend <0.001). Although there was a better model fit when WC, WSR or WHR was added to a model with BMI (P < 0.05; likelihood ratio test), the changes in PR and AUC were <10 % and <5 %, respectively. The sex-specific AUC for the prediction of hypertension by BMI (of 0.7-0.8) was similar to that by WC, WSR or WHR.

CONCLUSIONS

The waist indices do not perform better than BMI or markedly enhance the prediction of increased hypertension risk by BMI in Chinese adults.

Is the association of type II diabetes with waist circumference or waist-to-hip ratio stronger than that with body mass index?

In total, 17 prospective and 35 cross-sectional studies in adults aged 18-74 years, with the aim of comparing betweenbody mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) in their relation to the incidence and prevalence of type II diabetes, were reviewed. Among these studies, only a few have used C-statistic, paired homogeneity test or log-likelihood ratio test for formally comparing the differences. Five prospective studies, in which formal statistic tests have been made, came out with inconsistent findings: two results were in favour of WC in Mexicans African Americanss, respectively, one result was in favour of BMI in Pima Indians, and no difference was found in the other 2 studies. Among the 11 cross-sectional studies that have formally tested the differences, most found a higher odds ratio or slightly larger area under the ROC curve (AUC) for WC than for BMI. A meta-analysis based on the individual data of the Asian cohorts using a paired homogeneity test showed, however, that there was no difference in odds ratio between BMI and WC in Chinese, Japanese, Indian, Mongolian and Filipino men. In conclusion, all studies included in this review showed that either BMI or WC (WHR) predicted or was associated with type II diabetes independently, regardless of the controversial findings on which of these obesity indicators is better.

Métodos de avaliação da composição corporal em crianças

OBJETIVO: Revisar as principais técnicas de avaliação da composição corporal de crianças, enfatizando os estudos de validação. FONTES DE DADOS: Foi realizada uma busca nas principais bases científicas em saúde (SciELO, Science Direct e Pubmed), utilizando-se os descritores: "validação", "composição corporal", "criança", "índice de massa corporal", "pesagem hidrostática", "plestimografia", "bioimpedância elétrica", "pregas cutâneas", "antropometria", "circunferência da cintura" e respectivos vocábulos em inglês e espanhol. Foram selecionados artigos publicados entre 1990 e 2007e trabalhos clássicos referentes ao tema, publicados anteriormente. SÍNTESE DOS DADOS: Os métodos indiretos mais utilizados para avaliação da composição corporal de crianças são a plestimografia e a absortometria radiológica de dupla energia. Dentre os métodos duplamente indiretos, os mais utilizados são o índice de massa corporal, as pregas cutâneas, a bioimpedância elétrica, a circunferência da cintura, a relação cintura/quadril, o índice de conicidade e a relação cintura/estatura, sendo que as maiores correlações encontradas foram para a bioimpedância elétrica e o índice de massa corporal. CONCLUSÕES: Existem vários métodos para avaliar a composição corporal em crianças, cada um com suas vantagens e desvantagens. Ao definir o melhor método, é preciso eleger aquele que melhor detecte o problema que se pretende corrigir, levando em consideração os custos, o nível de treinamento dos avaliadores, o tempo de execução, a receptividade da população e os possíveis riscos à saúde.

The association between body mass index and hypertension is different between East and Southeast Asians

BACKGROUND

Few studies have allowed direct comparison of the association between body mass index (BMI; in kg/m2) and hypertension in different Asian ethnicities.

OBJECTIVE

We compared the association of BMI with hypertension in Chinese, Indonesian, and Vietnamese adults and determined BMI cutoffs that best predicted hypertension in these populations.

DESIGN

We included 7562 Chinese, 18,502 Indonesian, and 77,758 Vietnamese participants aged 18-65 y. Blood pressure, weight, and height were measured by trained health workers. To define an optimal BMI cutoff, we computed and searched for the shortest distance on receiver operating characteristic curves.

RESULTS

Despite a low mean BMI, the prevalences of hypertension in Chinese, Indonesian, and Vietnamese men were 22.9%, 24.8%, and 14.4%, respectively, and in women were 16.6%, 26.9%, and 11.7%, respectively. At all BMI levels, the sex-specific prevalence of hypertension was higher in Indonesian adults than in Chinese and Vietnamese adults (P < 0.05 at almost all BMI levels). The overall and stratified analyses suggested optimal BMI cutoffs of 23-24, 21-22.5, and 20.5-21 for Chinese, Indonesian, and Vietnamese adults, respectively. The cutoffs were approximately 0.5-1.0 units higher in women than in men and in the older (41-65 y) than in the younger (18-40 y) participants.

CONCLUSIONS

The study showed an ethnic difference in the BMI-hypertension association and in optimal BMI cutoffs between Chinese, Indonesian, and Vietnamese adults. Country-specific or even country-, sex-, and age-specific BMI cutoffs might be needed to identify persons at high risk of cardiovascular diseases.

Anthropometric predictors of incident type 2 diabetes mellitus in Iranian women

BACKGROUND AND OBJECTIVES

Studies have shown a strong association between excess weight and risk of incident diabetes in Iranian women. Therefore, we investigated anthropometric indices in the prediction of diabetes in Iranian women.

SUBJECTS AND METHODS

We examined 2801 females aged > or =20 years (mean [SD] age, 45.2 [12.9] years) in an Iranian urban population who were non-diabetic or had abnormal glucose tolerance at baseline. We estimated the predictive value of central obesity parameters (waist circumference [WC], waist-to-hip ratio [WHR], waist-to-height ratio [WHtR], body mass index [BMI]) in the prediction of diabetes. We classified each parameter in quartiles and compared the lowest with the highest quartile after adjusting for confounding variables, including age, hypertension, triglyceride levels, HDL-cholesterol, family history of diabetes, and abnormal glucose tolerance in a multivariate model. Receiver operator characteristic (ROC) curves were used to determine the predictive power of each variable.

RESULTS

Over a median follow up of 3.5 years (11 months-6.3 years), 114 individuals developed diabetes (4.1%). The risk for developing diabetes was significantly higher for the highest quartile of BMI, WC, WHR and WHtR, respectively, compared to the lowest quartile, and the risk decreased but remained statistically significant when abnormal glucose tolerance was included in the multivariate model. WHtR had the highest area under the ROC curve.

CONCLUSIONS

In Iranian women, BMI, WC, WHR, WHtR were predictive of development of type 2 diabetes, but WHtR was a better predictor than BMI.

Relationship between alanine aminotransferase levels and metabolic syndrome in nonalcoholic fatty liver disease

OBJECTIVE

To investigate the relationship between alanine aminotransferase (ALT) levels and metabolic syndrome (MS) in nonalcoholic fatty liver disease (NAFLD).

METHODS

A total of 26527 subjects who received medical health checkup in our hospital from January 2005 to July 2007 were enrolled in the study. The diagnosis of fatty liver was based on ultrasound imaging. MS was defined according to the criteria of the Adult Treatment Panel III. ALT, triglyceride (TG), high density lipoprotein cholesterol (HDL-c), fasting plasma glucose (FPG), height, weight, waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in each subject to analyze the relationship between MS and ALT activity.

RESULTS

(1) The prevalence of NAFLD in men (30.94%) was significantly higher than that in women (15.65%); (2) The incidence of MS in NAFLD (33.83%) was significantly greater than that in non-NAFLD (10.62%); (3) Of the 6470 subjects with NAFLD, in the age-adjusted partial correlation analysis, there were statistically significant correlations between the ALT levels and most metabolic risk factors in each sex (P<0.01), except that ALT levels had no correlation with HDL-c in women. Moreover, in the multiple stepwise regression analysis, SBP lost its significance, and WC, body mass index (BMI), age, DBP, TG and FPG were independently associated with ALT levels in both sexes (P<0.05). HDL-c remained significant and was independently related to ALT levels in men; (4) ALT levels were significantly higher in subjects with MS compared to those without MS (P<0.001). Mean ALT levels increased with the number of MS components in each sex (P<0.05 for trend).

CONCLUSION

We found a strong relationship between ALT levels and MS in NAFLD and revealed that the cluster of MS components might be the predictor for ALT elevations.

Blood pressure has a greater impact on cardiovascular mortality than other components of metabolic syndrome in Koreans

OBJECTIVE

Limited information is currently available on the association of metabolic syndrome or individual components with risk of cardiovascular morbidity and mortality in diverse populations. Here, we investigate the relationship of metabolic syndrome and its individual components with cardiovascular mortality in Korean adults.

METHODS

Data were obtained from 57,237 patients (32,819 men and 24,418 women), aged 40-89 years, subjected to regular health examinations at the Health Promotion Center of Asan Medical Center, Seoul, Korea (1999-2001) and subsequently followed up for a median time of 5.6 years. The risk of cardiovascular mortality was analyzed in relation to metabolic syndrome and its individual components.

RESULTS

The risk of cardiovascular mortality attributable to elevated blood pressure was approximately 52% in men and 72% in women, respectively. Compared to subjects without metabolic syndrome, individuals with metabolic syndrome presented a relative risk (RR) of cardiovascular disease (CVD)-induced death of 1.75 (95% CI, 1.15-2.66). After mutual adjustment for the individual components of metabolic syndrome, elevated blood pressure was significantly associated with CVD death, with RR values of 2.08 (95% CI, 1.27-3.42) in men and 3.56 (95% CI, 1.55-8.19) in women.

CONCLUSION

In Koreans, metabolic syndrome increases the risk of CVD death, with the blood pressure component being the key predictor of mortality.

Waist to height ratio is a simple and effective obesity screening tool for cardiovascular risk factors: Analysis of data from the British National Diet And Nutrition Survey of adults aged 19-64 years

OBJECTIVE AND METHOD

To analyse data from the nationally representative National Diet and Nutrition Survey (NDNS) collected in 2000/2001 and to investigate how the BMI and two proxy indicators of central fat distribution, namely the waist circumference and the waist to height ratio (WHtR), are associated with each other and with cardiovascular disease (CVD) risk factors.

RESULTS

Screening health risk by BMI alone would 'miss' 35% of men and 14% of women who are within the normal BMI range (18.5-25 kg/m(2)) but have central fat distribution, defined by WHtR > 0.5. In the total population this equates to 17% of all men and 6% of all women who would be inadequately screened by BMI alone. Compared to BMI, WHtR was more closely associated with CVD risk factors among both men and women. Furthermore, in a combined analysis of men and women, central fat distribution with a normal BMI was associated with higher levels of CVD risk factors than being overweight without central fat distribution.

CONCLUSION

WHtR is a simple and effective, non-invasive screening tool for CVD risk factors. Our proposed boundary value of 0.5 translates into a simple public health message: 'Keep your waist circumference to less than half your height'.

Waist-to-height ratio and coronary artery disease in Taiwanese type 2 diabetic patients

Waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHeiR), and BMI are indicators for obesity. This study examined the usefulness of these indicators for coronary artery disease (CAD) in Taiwanese type 2 diabetic patients. A total of 1,345 (646 men and 699 women) patients aged 63.3 +/- 11.5 years were studied. CAD was defined by history or Minnesota-coded electrocardiogram. The relative importance was evaluated by the magnitude of adjusted odds ratio per 1-s.d. increment, the decrease in -2 log likelihood after adding the index to the logistic model, the c-index, and the Akaiki's information criterion (AIC). Results showed that the four indices were highly intercorrelated and except BMI for men, all indices differed significantly between patients with and without CAD in either sex. In logistic regressions, the respective adjusted odds ratios for WC, WHR, WHeiR, and BMI for every 1-s.d. increment were 1.209 (1.010-1.448), 1.109 (0.935-1.316), 1.231 (1.027-1.474), and 1.207 (0.997-1.461) for men; and were 1.176 (0.995-1.390), 1.105 (0.923-1.322), 1.280 (1.079-1.518), and 1.277 (1.083-1.507) for women. Only WHeiR was significant for both sexes and it also showed the greatest decrease in -2 log likelihood, the largest magnitude of odds ratio, and the smallest AIC while compared with the other indices in either sex. It is concluded that WHeiR has the superiority of independent association with CAD and the highest magnitude of association than WC, WHR, and BMI in both sexes. The usefulness of WHeiR should not be neglected in clinical practice.

Comparison of Waist Circumference, Body Mass Index, Percent Body Fat and Other Measure of Adiposity in Identifying Cardiovascular Disease Risks among Thai Adults

OBJECTIVE

To compare the abilities of body mass index (BMI), percent body fat (%BF), waist circumference (WC), waist-hip ratio (WHR) and waist-height ratio (WHtR) to identify cardiovascular disease risk factors.

METHODS

This cross-sectional study is comprised of 1,391 Thai participants (451 men and 940 women) receiving annual health check-ups. Spearman's rank correlation was used to determine the association of the five anthropometric indices with metabolic parameters including fasting plasma glucose, triglyceride, high density lipoprotein and blood pressure. The prevalence of cardiovascular disease risk factors was determined according to tertile of each anthropometric measure. Receiver operating characteristic (ROC) curves were plotted to compare anthropometric measure as predictors of the prevalence of cardiovascular risk factors.

RESULTS

Metabolic parameters were more strongly associated with %BF and WHR and least correlated with BMI in men. Among women, BMI was most strongly correlated with metabolic parameters. In both genders, the prevalence of cardiovascular disease risk factors increased across successive tertiles for each anthropometric measure. Review of ROC curves indicated that %BF and WHR performed slightly better than other measures in identifying differences in CVD risk factors among men. BMI performed at least as well or better than other measures of adiposity among women.

CONCLUSIONS

These findings confirm high correlations between anthropometric measures and metabolic parameters. BMI, WC and other measures were not materially different in identifying cardiovascular disease risk factors. Although small differences were observed, the magnitudes of those differences are not likely to be of public health or clinical significance.

Optimal cutoff values for overweight: using body mass index to predict incidence of hypertension in 18- to 65-year-old Chinese adults

Studies aimed at identifying BMI cutoffs representing increased diseased risk for Asians are typically based on cross-sectional studies. This study determines an optimal BMI cutoff for overweight that represents elevated incidence of hypertension in Chinese adults with data from the China Health and Nutrition Survey 2000-2004 prospective cohort. Cumulative incidence was calculated by dividing new cases of hypertension over the study period by the total at-risk population, aged 18-65 y, in 2000. Sex-specific receiver operating characteristic curves were used to assess the sensitivity and specificity of BMI as a predictor of hypertension incidence. Four-year cumulative incidences of hypertension (13% for women and 19% for men) were related (P < 0.005) to the increase in BMI. The crude area under the curves (AUC) were 0.62 (95% CI: 0.59-0.65) and 0.62 (95% CI: 0.58-0.65) for men and women, respectively; the age-adjusted AUC were 0.68 (95% CI: 0.65-0.70) and 0.71 (95% CI: 0.68-0.74) for men and women, respectively. A BMI of 23.5 kg/m(2) for women and 22.5 kg/m(2) for men provided the highest sensitivity and specificity (60%). The finding was consistent in different age groups. A BMI level of 25 kg/m(2) provided lower sensitivities (36% for women and 29% for men) with higher specificities (80% for women and 85% for men). Our study supported the hypothesis that the BMI cutoff to define overweight should be lower in Chinese than that in Western populations.

Are Asians at greater mortality risks for being overweight than Caucasians? Redefining obesity for Asians

OBJECTIVES

To assess whether overweight Asians, assessed on the basis of WHO criteria, are at greater mortality risk than overweight Caucasians, and to determine whether alternative cut-off points (BMI = 23.0-24.9 kg/m2 for overweight and BMI >or= 25.0 kg/m2 for obesity) suggested by the WHO Western Pacific Regional Office are appropriate.

DESIGN

The cohort was followed prospectively until the end of 2001. All-cause and CVD mortality risks of the overweight and obese group, relative to the reference group (BMI = 18.5-24.9 or 18.5-22.9 kg/m2), were assessed using Cox regression analysis, adjusting for age, smoking and gender. Excess deaths were estimated with a method proposed by the US Centers for Disease Control and Prevention.

SETTING

National Health Interview Survey (NHIS 2001) and a middle-aged perspective cohort in Taiwan.

SUBJECTS

Subjects comprised 36 386 civil servants and school teachers, aged 40 years and older, who underwent a medical examination during 1989-1992.

RESULTS

In the WHO-defined overweight group, Asians showed a significant increase in all-cause mortality risk compared with Caucasians. Asians showed risks equivalent to Caucasians' at lower BMI (around 5 units). Every unit of BMI increase, at 25.0 kg/m2 or above, was associated with a 9 % increase in relative mortality risk from all causes. Applying a cut-off point of 25.0 kg/m2 for obesity would result a prevalence of 27.1 %, while the traditional WHO cut-off point of 30.0 kg/m2 yielded obesity prevalence of 4.1 %. Excess deaths due to obesity accounted for 8.6 % of all deaths and 21.1 % of CVD deaths, based on the alternative cut-offs.

CONCLUSIONS

In this Asian population, significant mortality risks started at BMI >or= 25.0 kg/m2, rather than at BMI >or= 30.0 kg/m2. The study supports the use of BMI >or= 25.0 kg/m2 as a new cut-off point for obesity and BMI = 23.0-24.9 kg/m2 for overweight. The magnitude of obesity-attributable deaths has been hitherto under-appreciated among Asians.

A simple clinical score for type 2 diabetes mellitus screening in the Canary Islands

AIM

To develop a straightforward risk score for type 2 diabetes (DM2) screening to use in clinical practice.

METHODS

A sample of 6237 adult inhabitants of the Canary Islands (Spain) was randomly divided into two subgroups: one yielded data used to develop the instrument, and the other yielded data used for validation testing. Performance of the instrument was compared in persons with clinically diagnosed DM2 and undiagnosed diabetes. The risk score, calculated by multivariate logistic regression, included the potential risk variables that yielded the highest odds ratio in the univariate analysis. A cut-off point for screening purposes was established at a 99% negative predictive value.

RESULTS

In men, variables included in the risk score were age, waist/height ratio, familial antecedents of diabetes, and systolic blood pressure (ROC curve 0.837, 95% CI: 0.803-0.871). In women, the risk score contained the same variables plus gestational diabetes history (ROC curve 0.874, 95% CI: 0.847-0901). Excluding systolic blood pressure from the score had no significant effect on the area under the curve. This instrument resulted valid only for people aged less than 55 years.

CONCLUSIONS

This simple risk score for DM2 would be easy to apply in clinical practice.

Urban—Rural Disparity of Overweight, Hypertension, Undiagnosed Hypertension, and Untreated Hypertension in China

The objective of this study was to examine the urban—rural variations in the prevalence of overweight, hypertension, undiagnosed hypertension, and untreated hypertension among adults. The China Health and Nutrition Survey was used to study adults 25 to 65 years old. Logistic regression was used to obtain the odds ratios (ORs) after adjusting for demographic, socioeconomic, and lifestyle variables. Urban adults have a higher probability of being overweight (OR = 1.18, P < .01) and having hypertension (OR = 1.19, P < .1). After further controlling for lifestyle variables, the difference is not significant. Urban hypertensive adults are less likely to be undiagnosed (OR = 0.54, P < .001) and untreated (OR = 0.53, P < .001), even after controlling for socioeconomic and lifestyle variables, suggesting that there are other reasons for the urban—rural disparity of undiagnosed and untreated hypertension. This finding suggests that modifying lifestyles is critical in preventing urban adults from being overweight. Interventions targeting rural adults should promote the awareness and treatment of hypertension.

Comparison of body fat estimation using waist:height ratio using different 'waist' measurements in Australian adults

The objective of the present study was to determine differences in predicting total and regional adiposity using the waist:height ratio (WHtR) calculated using different 'waist' measurements. Body composition of ninety-five males and 121 female Australian adults (aged 20 years and above) was measured using dual-energy X-ray absorptiometry. The WHtR was calculated using: (1) the narrowest point between the lower costal border and the top of the iliac crest (WHtR-W), and (2) at the level of the umbilicus (WHtR-A). Relationships between calculated WHtR and measured body composition, such as percentage body fat (%BF) and percentage trunk fat (%TF) were determined. Values obtained from WHtR-A were significantly greater than WHtR-W in both groups (P < 0.05). While no correlation differences between WHtR-W and WHtR-A in relation to body composition variables were observed, females showed significantly lower correlation with lean mass compared with BMI. Regression analyses showed that neither WHtR had an age influence on %TF estimation. Estimated %BF and %TF were comparable for both WHtR and also with estimated values using a BMI of 25 kg/m2. Sensitivity of excess %BF and %TF increased by using WHtR-A, particularly in females. In conclusion, the umbilicus measurement may be better than using the narrowest site in the WHtR calculation, particularly in females. To improve the screening ability of the WHtR and make comparisons between studies easier there may be a need to standardise the measurement location. Further studies are recommended to confirm the findings across different ethnic groups.

Overweight male personnel of the Japan Self-Defense Forces with body mass indices of 23.0-24.9 and obesity-related metabolic disorders

OBJECTIVES

To assess the validity of the criterion of overweight for Asian people that is recommended by Western Pacific Region of the World Health Organization.

METHODS

We carried out a cross-sectional analysis of the association between the criterion of overweight for ethnic Asian people--body mass indices (BMI) of 23.0-24.9 kg/m(2)--and the presence of obesity-related metabolic disorders among middle-aged Japanese men (n = 974, age range 51-59).

RESULTS

The odds ratios (95% confidence interval) of overweight to those with normal weight (BMI < 23.0 kg/m(2)) were 1.61 (1.11-2.33) for the presence of impaired glucose tolerance, 1.95 (1.30-2.93) for hypertension, 2.22 (1.63-3.03) for hypercholesterolemia, 2.83 (2.02-3.97) for hypertriglyceridemia, and 2.06 (1.06-4.00) for hyperuricemia. Overweight was not associated with the presence of type 2 diabetes or with high gamma-glutamyl transferase in the present study (odds ratios: 1.09 and 1.05, respectively). Adjustment for age, rank, and lifestyle factors affected the results only slightly.

CONCLUSIONS

Based on these results, we conclude that the Asian criterion of overweight appears to be rational in terms of its association with obesity-related metabolic disorders in male personnel of the Japan Self-Defense Forces in their fifties.

Obesity and its related diseases in Taiwan

Obesity is related to increased morbidity and mortality, and prevails worldwide. It has become an important health issue and requires urgent attention. In Taiwan, overweight and obesity are defined as body mass index > or = 24 and 27 kg m(-2), respectively. These cut-offs differ from Caucasian standards, as Asians have higher comorbidities and fat mass at lower BMI levels than Caucasians. The prevalence of obesity and overweight in Taiwan are 19.2% and 30.5% in men, 13.4% and 21.3% in women. This implies that a more profound increase in obesity prevalence is found in men than in women. A high-fat diet, sedentary lifestyle and betel nut chewing may increase substantially this obesity epidemic. Recently, type 2 diabetes mellitus has been found to be the most common type of diabetes, and obesity is significantly related to type 2 diabetes in children. In addition, obesity is associated with cardiovascular diseases risk factors and cannot be neglected in elderly. Therefore, a comprehensive prevention and management programme of obesity is urgently warranted for controlling the growing obesity trend and its related diseases in Taiwan.

Prevalence and independent predictors of insulin resistance in children from Crete, Greece: the Children Study

BACKGROUND

It has been proposed that insulin resistance (IR) is associated with the development of Type 2 diabetes mellitus and cardiovascular disease. The aim of this study is to determine the prevalence of IR in Greek schoolchildren and to investigate factors associated with IR.

METHODS

Between October 2005 and March 2006, 522 children were recruited from Crete. Physical activity and dietary habits, anthropometric and biochemical characteristics, as well as medical history of pupils' parents were recorded. IR was estimated using the homeostasis model assessment (HOMA-IR), fasting glucose-to-insulin ratio (FGIR) and quantitative insulin sensitivity check index (QUICKI). Multiple linear regression was used to determine independent predictors for IR.

RESULTS

Fasting insulin levels and HOMA-IR scores were higher in obese children and girls compared with their normal-weight peers (P < 0.001). Moreover, the former had lower values in FGIR and QUICKI indices compared with the latter, indicating that obese children and girls are more insulin resistant compared with their counterparts (P < 0.001). The prevalence of IR was 9.2% (2.9% in normal-weight, 10.5% in overweight and 31.0% in obese children), using as a threshold HOMA-IR > 2.10 97.5th percentile of normal-weight participants). Multiple linear regression revealed that central adiposity, female gender and intake of simple carbohydrates is associated positively with HOMA-IR values, even after controlling for many other factors.

CONCLUSION

These findings demonstrate that girls and obese children, particularly those with central adiposity, are at high risk of developing IR. Therefore, these groups should be targets of Type 2 diabetes mellitus and cardiovascular disease preventive interventions.

How does ethnicity affect the association between obesity and diabetes?

AIMS

To examine the utility of body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHR) in assessing diabetes risk across different ethnic groups.

METHODS

Cross-sectional analysis of data for eight ethnic groups from the 2003-2004 National Health and Nutrition Examination Survey and 2003-2004 Health Survey for England was performed. In 11 624 adults > or = 20 years old, self-reported as US White, US Black, Mexican American, English White, English Black, Bangladeshi, Pakistani, Indian or Chinese the presence of diabetes, defined as self-report of doctor diagnosis or glycated haemoglobin (HbA1c) > 6.1%, was ascertained. Comparisons of proportions were made using chi2-tests. Receiver operating characteristic (ROC) curves were calculated for BMI, WC and WHR predicting diabetes.

RESULTS

Other ethnic groups had a higher prevalence of diagnosed diabetes than English Whites. The crude prevalence of diabetes in English Whites of normal weight (BMI < 25 kg/m2) was 3.4%. Higher prevalences were seen in other ethnic groups (5.0-10.9%). Based on ROC curves, both WC and WHR had better discriminating ability for diabetes than BMI for both genders and some ethnic groups.

CONCLUSIONS

Ethnic differences exist in the crude prevalence of diabetes, even in those characterized as normal weight by BMI. Thus, clinicians need to exercise caution in interpreting diabetes risk associated with a normal BMI. The use of other anthropometric measures, such as WC or WHR, may improve risk determination across different ethnic groups. More research is needed to determine the thresholds for different anthropometric measures that improve diabetes risk determination.

Gender difference on the development of metabolic syndrome: a population-based study in Taiwan

Little is known regarding the development of metabolic syndrome. This study examining gender difference in the characteristics of metabolic components aimed to estimate the development of metabolic syndrome in both genders. This nation-wide, population-based survey included 5,880 men and women aged 20-79 years in Taiwan. Metabolic syndrome was defined by the revised National Cholesterol Education Program Adult Treatment Panel III, with adoption of the Asian criteria for abdominal obesity. The results indicate that metabolic syndrome was prevalent in 20.4% of the men and 15.3% of the women. Lipid components occurred the earliest in both genders. The appearance of the first isolated component was earlier in women than in men (mean age 43.4 vs. 45.6 years, P < 0.05). In contrast, the mean prevalent age of metabolic syndrome appeared earlier in men than in women by 4.9 years (mean age 51.3 vs. 56.2 years, P < 0.05). The differences in prevalent age from the appearance of any isolated component to metabolic syndrome were 12.8 years in women and 5.7 years in men, respectively. If men had a body mass index less than 23 kg/m(2) and exercise habits, the difference in the prevalent age from the isolated component to metabolic syndrome was 15.4 years, longer than for all women subjects. We conclude lipid components appeared the earliest. Women had the first isolated component earlier, presenting as metabolic syndrome later than men. The development of metabolic syndrome was slower in subjects without overweight characteristics and with exercise habits.

Prevalence and significance of generalized and central body obesity in an urban Asian Indian population in Chennai, India (CURES: 47)

OBJECTIVES

To determine the prevalence of generalized and abdominal obesity in urban Asian Indians and compare the association of body mass index (BMI) and waist circumference (WC) with metabolic risk variables.

METHODS

Subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES) carried out between 2001 and 2004 and involved 2350/2600 eligible subjects (response rate 90.4%). Anthropometric measurements, lipids and oral glucose tolerance tests were carried out. Generalized obesity (BMI>or=23 kg m(-2)) and abdominal obesity (WC>or=90 cm in men and >or=80 cm in women) were defined using WHO Asia Pacific guidelines.

RESULTS

The age standardized prevalence of generalized obesity was 45.9% (95% CI: 43.9-47.9%), (women: 47.4%; men: 43.2%, P=0.210), while that of abdominal obesity was 46.6% (95% CI: 44.6-48.6%), (women: 56.2%> men: 35.1%, P<0.001). Area under the curve for identifying subjects with any three metabolic risk factors using BMI was 0.66, 95% CI: 0.63-0.69, P<0.001, while, for WC, it was 0.70, 95% CI: 0.66-0.74, P<0.001 for men, and 0.69, 95% CI: 0.65-0.74, P<0.001 for women. Isolated generalized obesity (normal WC, increased BMI) was present in 12.7% of men and 6.1% of women. Isolated abdominal obesity (increased WC, normal BMI) was present in 4.7% of men and 14% of women. Combined obesity was present in 32.6% of men and 43.3% of women.

CONCLUSIONS

In Asian Indians, the prevalence of combined obesity is high among both sexes, while isolated generalized obesity is more common in men and isolated abdominal obesity more common in women. However, these prevalence rates vary markedly depending on cut points used. WC is a better marker of obesity-related metabolic risk than BMI in women compared to men in this population.

Ten-year cardiovascular disease risk of metabolic syndrome without central obesity in middle-aged chinese

This study aimed to examine the relation between central obesity and other metabolic disorders of metabolic syndrome (MS) and compare the long-term risks of cardiovascular disease (CVD) between patients with MS with or without central obesity in middle-aged Chinese. The study included 30,378 Chinese aged 35 to 64 years at baseline with complete measurements for MS components and follow-up data for new acute CVD events from 1992 to 2003. The 10-year relative and absolute CVD risks in the MS groups with or without central obesity were compared. Results showed that 78% of patients with MS had central obesity and 22% with MS had no central obesity, diagnosed using updated Adult Treatment Panel III criteria with cut-off values appropriate for Asian populations. Central obesity, as well as other metabolic disorders in patients with MS, except for increased triglycerides, increased CVD risk significantly. There were no significant differences in 10-year absolute and relative risks of coronary heart disease events and ischemic CVD events between the 2 MS groups. In conclusion, MS with or without central obesity has a significantly increased 10-year risk of CVD in middle-aged Chinese.

Anthropometric predictors for the risk of chronic disease in non-diabetic, non-hypertensive young Mexican women

OBJECTIVES

To assess the ability of anthropometric measurements to identify young women at risk of developing diabetes, hypertension and heart disease in the future and to compare cut-off points for common anthropometric measures established with receiver-operating characteristic (ROC) curves with those reported in the literature.

DESIGN

Cross-sectional study.

SUBJECTS

Eight hundred and two young Mexican women living in semi-urban poverty. MEASUREMENTS/METHODS: The ability of anthropometric measures of fatness and fat distribution (body mass index (BMI), summed skinfold thickness (SST), waist circumference (WC), waist-to-hip ratio (WHR), conicity index (CI), abdominal volume index (AVI)) to predict risk of future disease (pre-diabetes: fasting blood glucose 100-126 mg dl-1; pre-hypertension: systolic blood pressure 120-139 mmHg and/or diastolic blood pressure 80-89 mmHg; hypertriglyceridaemia: triglycerides > or =150 mg dl-1; or a combination of risk factors) was assessed using ROC curve analysis.

RESULTS

Twenty-three of the 802 women who were interviewed had incomplete data and 50 (6.4%) were eliminated from the analysis due to hypertension and/or diabetes. Mean age of the remaining 729 women was 29.6 +/- 5.4 years and mean BMI was 27.7 +/- 4.5 kg m-2. There were no significant differences in the area under the ROC curve for BMI, WC, AVI or SST for any of the four outcomes. However, these indices performed significantly better than WHR and CI (P < 0.05). The BMI cut-off points that maximised sensitivity and specificity for the four outcomes were in the range of 27.7-28.4 kg m-2, and for WC were 89.3-91.2 cm. To detect 90% of the cases of any metabolic alteration, the necessary BMI cut-off was 26.1 kg m-2. Younger women (<25 years) were at greater risk than older women for a given BMI increment (P < 0.05).

CONCLUSIONS

We found that BMI and WC cut-off points commonly used for the identification of risk of existing disease were also appropriate in this population for the identification of risk in the future among women without diabetes or hypertension. The early identification of at-risk individuals, prior to the onset of disease, is fundamental particularly in the context of a country with scarce resources that is rapidly undergoing nutrition transition.