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

Shared and Distinct Gut Microbial Profiles in Saudi Women with Metabolically Healthy and Unhealthy Obesity

BACKGROUND

Mounting evidence suggests a pivotal role for the gut microbiome in energy disequilibrium characteristic of obesity. The clinical utility of microbial profiling for the distinction between metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) remains ill-defined. We aim to probe microbial composition and diversity in young adult Saudi females with MHO and MUO. This observational study included anthropometric and biochemical measurements and shotgun sequencing of stool DNA for 92 subjects. α- and β-diversity metrics were calculated to determine the richness and variability in microbial communities, respectively. Results showed that Bacteroides and Bifidobacterium merycicum were less abundant in MUO compared to healthy and MHO groups. BMI was negatively correlated with B. adolescentis, B. longum, and Actinobacteria in MHO, while being positively correlated with Bacteroides thetaiotaomicron in both MHO and MUO. Positive correlations between waist circumference and B. merycicum and B. thetaiotaomicron were observed in MHO and MUO, respectively. Compared to MHO and MUO groups, higher α-diversity was detected in healthy individuals who also had higher β-diversity compared to those with MHO. We conclude that modulation of the gut microbiome cohorts through prebiotics, probiotics, and fecal microbiota transplantation may be a promising preventive and therapeutic approach to obesity-associated disease.

Anthropometric measures of obesity and associated cardiovascular disease risk in the Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study

BACKGROUND

Accurately defining obesity using anthropometric measures that best capture obesity-related risk is important for identifying high risk groups for intervention. The purpose of this study is to compare the association of different anthropometric measures of obesity with 10-year cardiovascular disease (CVD) risk in adults in the Eastern Caribbean.

METHODS

Data from the Eastern Caribbean Health Outcomes Research Network (ECHORN) Cohort Study (ECS) were analyzed. The ECS is comprised of adults aged 40 and older residing in the US Virgin Islands, Puerto Rico, Barbados, and Trinidad. 10-year CVD risk was calculated using the American Heart Association (ACC/AHA) ASCVD Risk Algorithm and categorized in the following high-risk groups: > 7.5, > 10, and > 20%. Logistic regression was used to examine associations between four anthropometric measures of obesity (BMI, waist circumference, waist-to-hip ratio, waist-to height ratio) and 10-year CVD risk.

RESULTS

Mean age (SD) of participants (n = 1617) was 56.6 years (±10.2), 64% were women, 74% were overweight/obese, and 24% had an ASCVD risk score above 10%. Elevated body mass index (BMI, > 30 kg/m2) and waist circumference were not associated with CVD risk. Elevated waist-to-hip ratio (WHR, > 0.9 men, > 0.85 women) and elevated waist-to-height ratio (> 0.5) were associated with all three categories of CVD risk. Area under the receiver curve was highest for WHR for each category of CVD risk. Elevated WHR demonstrated odds of 2.39, 2.58, and 3.32 (p < 0.0001) for CVD risk of > 7.5, > 10 and > 20% respectively.

CONCLUSION

Findings suggest that WHR is a better indicator than BMI of obesity-related CVD risk and should be used to target adults in the Caribbean, and of Caribbean-descent, for interventions.

Discriminatory Capacity of Anthropometric Indices for Cardiovascular Disease in Adults: A Systematic Review and Meta-Analysis

INTRODUCTION

Obesity is one of the main risk factors for cardiovascular disease (CVD) and cardiometabolic disease (CMD). Many studies have developed cutoff points of anthropometric indices for predicting these diseases. The aim of this systematic review was to differentiate the screening potential of body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) for adult CVD risk.

METHODS

We used relevant key words to search electronic databases to identify studies published up to 2019 that used receiver operating characteristic (ROC) curves for assessing the cut-off points of anthropometric indices. We used a random-effects model to pool study results and assessed between-study heterogeneity by using the I² statistic and Cochran's Q test.

RESULTS

This meta-analysis included 38 cross-sectional and 2 cohort studies with 105 to 137,256 participants aged 18 or older. The pooled area under the ROC curve (AUC) value for BMI was 0.66 (95% CI, 0.63-0.69) in both men and women. The pooled AUC values for WC were 0.69 (95% CI, 0.67-0.70) in men and 0.69 (95% CI, 0.64-0.74) in women, and the pooled AUC values for WHR were 0.69 (95% CI, 0.66-0.73) in men and 0.71 (95% CI, 0.68-0.73) in women.

CONCLUSION

Our findings indicated a slight difference between AUC values of these anthropometric indices. However, indices of abdominal obesity, especially WHR, can better predict CVD occurrence.

[Anthropometric measurements of general and central obesity and discriminative capacity on cardiovascular risk: RICARTO study]

INTRODUCTION AND OBJECTIVES

Overweight and obese patients have an increased risk of cardiovascular disease and general mortality. It is not clear which obesity index should be used in the clinic. The objective is to compare the relationship between body mass index (BMI), waist circumference (WC), waist-height ratio (WHR), and conicity index (Conicity-I) with 10-year Framingham cardiovascular risk (CVR).

MATERIAL AND METHODS

Population cross-sectional study in subjects ≥18years, residents in the Toledo (Spain) Health Area. Selection by random sampling. Measurements were made of the BMI, WC, and weight to height ratio with standardised methods. Framingham CVR. Calculation of AUC, and optimal cut-off points.

RESULTS

The study included 1,309 subjects, with mean age of 48.9±15.8years, and 55% women. The response rate was 36.6%. In women, the index that was best associated with CVR in women was the WC with an AUC=0.85 (95%CI: 0.81-0.88). In men it was the I-Conicity, with an AUC=0.81 (95%CI: 0.77-0.84). Cut points for BMI were similar in women (27.08kg/m²) and men (26.99kg/m²). The WC was lower in women (87.75cm) than in men (94.5cm). The WHR was higher in women (0.59) than in men (0.56). The I-Conicity was slightly lower in women (1.25) than in men (1.28). In women, all the ROC curves were closest to each other.

CONCLUSIONS

The central obesity indexes (WC and WHR) discriminated better than the BMI the CVR. In women, all the indices had greater AUCs than in men, except for the I-Conicity.

Lifestyle factors and macro- and micro-vascular complications among people with type 2 diabetes in Saudi Arabia

AIMS

The aim of this study is to identify lifestyle factors that place people with type 2 diabetes in Saudi Arabia at a greater risk of macro- and microvascular complications.

METHODS

A survey was conducted among adults with type 2 diabetes who attended diabetes centres in three major cities in Saudi Arabia. Participants were interviewed and their medical files were reviewed for lab test results and documented comorbidities. Associations between complication and lifestyle factors were assessed using multiple logistic regression analysis.

RESULTS

A total of 1121 participants were recruited. Mean age was 57.6 (±11.1) years. The prevalence of coronary artery disease, diabetic foot, and stroke was 17.0%, 13.1% and 3.7%, and that of neuropathy, renal impairment, and retinopathy was 20.3%, 14.5%, and 42.8% respectively. Lifestyle factors associated with one or more of the complications were inadequate physical activity, longer sitting time, obesity, current or past smoking, passive smoking, hypertension, poor glycaemic control, low HDL and high triglycerides.

CONCLUSIONS

Diabetes complications are common among people with type 2 diabetes in Saudi Arabia. Life style factors such as inadequate physical activity, longer sitting time, obesity, smoking, hypertension, and poor control of blood glucose and lipids should be assimilated into complications prevention program.

Glycaemic control for people with type 2 diabetes in Saudi Arabia - an urgent need for a review of management plan

BACKGROUND

The aim of this study was to assess inadequate glycaemic control and its associated factors among people with type 2 diabetes in Saudi Arabia.

METHODS

A cross-sectional study design was used. Adults with type 2 diabetes attending diabetes centres in Riyadh, Hofuf and Jeddah cities were interviewed and their anthropometrics were measured. Their medical records were also reviewed to collect information related to recent lab tests, medications, and documented comorbidities. Multivariable logistic regression were used for data analysis.

RESULTS

A total of 1111 participants were recruited in the study. Mean age was 57.6 (±11.1) years, 65.2% of the participants were females, and mean HbA1c was 8.5 ± 1.9%. About three-fourths of participants had inadequate glycaemic control (≥ 7%). Multivariable analysis showed that age ≤ 60 years, longer duration of diabetes, living in a remote location, low household income, low intake of fruits and vegetable, low level of physical activity, lack of knowledge about haemoglobin A1c, high waist-hip ratio, low adherence to medication, and using injectable medications were independent risk factors for inadequate glycaemic control.

CONCLUSIONS

Inadequate glycaemic control is prevalent among people with type 2 diabetes in Saudi Arabia. In order to improve glycaemic control diabetes management plan should aim at controlling the modifiable risk factors which include low intake of fruits and vegetable, low level of physical activity, lack of knowledge about haemoglobin A1c, high waist-hip ratio, and low adherence to medications.

Anthropometric measures of central adiposity are highly concordant with predictors of cardiovascular disease risk in HIV patients

Background

Body fat redistribution and metabolic abnormalities found in HIV patients receiving highly active antiretroviral therapy (HAART) contribute to an atherogenic profile, increasing cardiovascular disease risk.

Objective

We aimed to evaluate adiposity measures/indexes and propose cutoffs associated with predictors of cardiovascular disease risk in HIV patients on HAART.

Design

To evaluate cardiovascular disease risk in this cross-sectional study, we conducted electrocardiogram exams and stress electrocardiography, measured the ankle brachial index and blood pressure arterial hypertension, conducted lipid biochemical tests, and measured blood glucose. We measured circumferences [waist (WC), hip, thigh, calf, neck, trunk] and skinfold thicknesses (biceps, triceps, subscapular, suprailiac), conducted bioelectrical impedance analysis (BIA), and calculated indexes [body mass index, waist-to-hip ratio, waist-to-thigh ratio, waist-to-calf ratio, waist-to-height ratio (WHtR), trunk-to-arm ratio, body mass index corrected for body fat mass, Body Adiposity Index, conicity index, body shape index, fat mass (percentage), and phase angle]. For evaluating the performance of all adiposity measures/indexes, we used receiver operating characteristic (ROC) curves.

Results

Measures of central adiposity WC and WHtR showed the best performances-WC area under the curve (AUC) for men: 0.83 (95% CI: 0.78, 0.89; P < 0.05); WC AUC for women: 0.86 (95% CI: 0.81, 0.91; P < 0.05); WHtR AUC for men: 0.83 (95% CI: 0.78, 0.88; P < 0.05); and WHtR AUC for women: 0.85 (95% CI: 0.80, 0.91; P < 0.05). All adiposity measures/indexes presented different cutoffs from those proposed for the HIV seronegative population. The cutoffs for WC were 87.75 cm (sensitivity: 82.2%; specificity: 75.5%) for men and 90.5 cm (sensitivity: 84.0%; specificity: 73.0%) for women.

Conclusions

The measures/indexes of central adiposity presented excellent associations with predictors of cardiovascular disease risk, and the use of the cutoffs proposed in the present study aims to contribute to the early identification of increasing risk of cardiovascular diseases, enabling interventions. This trial was registered at the Brazilian clinical trials registry Registro brasileiro de ensaios clínicos (Rebec) as RBR-9rcxbq.

Evaluation of the Alternative Healthy Eating Index as a predictor of 10-year cardiovascular disease risk in a group of Iranian employees

BACKGROUND

Noncommunicable diseases, of which almost half are some form of cardiovascular disease (CVD), have overtaken communicable diseases as the world's major disease burden. There is growing evidence that indices of diet quality could have an association with a decreased risk of CVD in several countries. We aimed to examine the association between diet quality, as measured by the Alternative Healthy Eating Index (AHEI), and 10-year predicted CVD risk based on the Framingham Risk Score (FRS) in a group of Iranian employees.

METHODS

A cross-sectional descriptive study was conducted on 296 (232 male, 64 female) employees aged ≥30 years selected by nonrandom sampling. AHEI was calculated according to a food frequency questionnaire with complementary questions on intake of cooking fats and oils among households. The 10-year risk of CVD was calculated based on FRS. Total and high-density lipoprotein-cholesterol, fasting blood sugar and blood pressure were measured to help in the calculation of FRS.

RESULTS

AHEI did not have a significant relationship with FRS (r = -0.02, P = 0.67). However, some of its components, such as the intake of nuts and soy groups (r = -0.11, P = 0.04) and fruits (r = -0.14, P = 0.01), had a significant relationship with a reduced risk of CVD. According to stepwise multiple linear regression results, for every single increase in the intake of fruit servings, there would be a 0.14 reduction in the 10-year CVD risk score (β = -0.14, P = 0.01).

CONCLUSIONS

The present study showed no significant relationship between AHEI and the 10-year predicted risk of CVD among Iranian employees.

Consensus clinical recommendations for the management of plasma lipid disorders in the Middle East

BACKGROUND

Plasma lipid disorders are key risk factors for the development of atherosclerotic cardiovascular disease (ASCVD) and are prevalent in the Middle East, with rates increasing in recent decades. Despite this, no region-specific guidelines for managing plasma lipids exist and there is a lack of use of guidelines developed in other regions.

METHODS

A multidisciplinary panel of regional experts was convened to develop consensus clinical recommendations for the management of plasma lipids in the Middle East. The panel considered existing international guidelines and regional clinical experience to develop recommendations.

RESULTS

The panel's recommendations include plasma lipid screening, ASCVD risk calculation and treatment considerations. The panel recommend that plasma lipid levels should be measured in all at-risk patients and at regular intervals in all adults from the age of 20years. A scoring system should be used to calculate ASCVD risk that includes known lipid and non-lipid risk factors. Primary treatment targets include low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol. Lifestyle modifications should be first-line treatment for all patients; the first-line pharmacological treatment targeting plasma lipids in patients at moderate-to-high risk of ASCVD is statin therapy, with a number of adjunctive or second-line agents available. Guidance is also provided on the management of underlying conditions and special populations; of particular pertinence in the region are familial hypercholesterolaemia, diabetes and metabolic dyslipidaemia.

CONCLUSIONS

These consensus clinical recommendations provide practicing clinicians with comprehensive, region-specific guidance to improve the detection and management of plasma lipid disorders in patients in the Middle East.

Prevalence and determinants of metabolic syndrome in Qatar: results from a National Health Survey

OBJECTIVES

To determine optimum measurements for abdominal obesity and to assess the prevalence and determinants of metabolic syndrome in Qatar.

DESIGN

National health survey.

SETTING

Qatar National STEPwise Survey conducted by the Supreme Council of Health during 2012.

PARTICIPANTS

2496 Qatari citizens aged 18-64 representative of the general population.

PRIMARY AND SECONDARY OUTCOME MEASURES

Measure of obesity (body mass index, waist circumference or waist-to-height ratio) that best identified the presence of at least 2 other factors of metabolic syndrome; cut-off values of waist circumference; frequency of metabolic syndrome.

RESULTS

Waist circumference ≥102 for men and ≥94 cm for women was the best predictor of the presence of other determinants of metabolic syndrome (raised blood pressure, fasting blood glucose, triglycerides and reduced high-density lipoprotein cholesterol). Using these values, we identified 28% of Qataris with metabolic syndrome, which is considerably lower than the estimate of 37% calculated using the International Diabetes Federation (IDF) criteria. Restricting the analysis to participants without known elevated blood pressure, elevated blood sugar or diabetes 16.5% would be classified as having metabolic syndrome. In a multivariable logistic regression analysis, the prevalence of metabolic syndrome increased steadily with age (OR=3.40 (95% CI 2.02 to 5.74), OR=5.66 (3.65 to 8.78), OR=10.2 (5.98 to 17.6) and OR=18.2 (7.01 to 47.5) for those in the age group '30-39', '40-49', '50-59', '60-64' vs '18-29'; p<0.0001), decreased with increasing educational attainment (OR=0.61 (0.39 to 0.96) for those who attained 'secondary school or more' compared with 'less than primary school'; p=0.03) and exercise (OR=0.60 (0.42 to 0.86) for those exercising ≥3000 vs <600 MET-min/week; p=0.006) but was not associated with smoking or diet.

CONCLUSIONS

Waist circumference was the best measure of obesity to combine with other variables to construct a country-specific definition of metabolic syndrome in Qatar. Approximately 28% of adult Qatari citizens satisfy the criteria for metabolic syndrome, which increased significantly with age. Education and physical activity were inversely associated with this syndrome.

Comparing the Ability of Anthropometric Indicators in Identifying Metabolic Syndrome in HIV Patients

BACKGROUND

Highly active antiretroviral therapy (HAART) can cause side effects in HIV patients, as the metabolic syndrome. Early identification of risk for development of cardiovascular diseases using available reliable and practical methods is fundamental. On this basis, the aim of this study was to compare the effectiveness of anthropometric indicators to identify metabolic syndrome in HIV patients on HAART.

METHODS

It is a cross-sectional study. A number of 280 stable HIV patients were studied. It measured weight, height, waist circumference (WC), hip circumference (HP), thigh circumference (TC) and calculated body mass index (BMI), body adiposity index (BAI), waist to hip ratio (WHR) and waist to thigh ratio (WTR). There was also a performance of biochemical tests of lipid profile and fasting glucose. Systemic blood pressure was measured. The criteria proposed by the National Cholesterol Education Program III (NCEP-ATP III) to metabolic syndrome classification was used. Individuals were divided in groups with or without metabolic alterations and their anthropometric indicators were compared. Receiver operating characteristic (ROC) curves were designed for each anthropometric indicator using the metabolic syndrome classification to identify sensitivity and specificity.

RESULTS

WC was a good tool to identify each metabolic disorder separately: total cholesterol (only females, p<0.05), triglycerides (only males, p<0.001), HDL cholesterol (p<0.05), LDL cholesterol (p<005) and fasting glycemic (p<005). WC also showed the best performance to identify metabolic syndrome in both genders (areas under the curve (AUCs): 0.79 and 0.76 for male and female, respectively), while BAI proved to be an inadequate indicator (AUCs: 0.63 and 0.67 for males and females), respectively, in this population.

CONCLUSIONS

The central adiposity measure (WC) had the best performance to identify metabolic syndrome, and it is a convenient, cheap and reliable tool that can be used in clinical practice routinely to prevent cardiovascular complications in HIV patients.

Optimal Cutoff Points of Anthropometric Parameters to Identify High Coronary Heart Disease Risk in Korean Adults

Several published studies have reported the need to change the cutoff points of anthropometric indices for obesity. We therefore conducted a cross-sectional study to estimate anthropometric cutoff points predicting high coronary heart disease (CHD) risk in Korean adults. We analyzed the Korean National Health and Nutrition Examination Survey data from 2007 to 2010. A total of 21,399 subjects aged 20 to 79 yr were included in this study (9,204 men and 12,195 women). We calculated the 10-yr Framingham coronary heart disease risk score for all individuals. We then estimated receiver-operating characteristic (ROC) curves for body mass index (BMI), waist circumference, and waist-to-height ratio to predict a 10-yr CHD risk of 20% or more. For sensitivity analysis, we conducted the same analysis for a 10-yr CHD risk of 10% or more. For a CHD risk of 20% or more, the area under the curve of waist-to-height ratio was the highest, followed by waist circumference and BMI. The optimal cutoff points in men and women were 22.7 kg/m(2) and 23.3 kg/m(2) for BMI, 83.2 cm and 79.7 cm for waist circumference, and 0.50 and 0.52 for waist-to-height ratio, respectively. In sensitivity analysis, the results were the same as those reported above except for BMI in women. Our results support the re-classification of anthropometric indices and suggest the clinical use of waist-to-height ratio as a marker for obesity in Korean adults.

Conicity Index and Waist-to-Hip Ratio Are Superior Obesity Indices in Predicting 10-Year Cardiovascular Risk Among Men and Women

BACKGROUND

Central obesity has been recognized as a main risk factor for cardiovascular (CV) events. Three popular central obesity indices are waist circumference, waist-to-hip ratio (WHR), and waist-to-height ratio; abdominal volume index and conicity index are 2 recent novel obesity indices. The main aim of this study is to determine the performance of these indices to best predict 10-year CV events.

HYPOTHESIS

Some obesity indices can be used to predict cardiovascular risk.

METHODS

In total, 3199 subjects (age range, 40-79 years) were enrolled in this cross-sectional study. The American College of Cardiology/American Heart Association and Framingham risk score tools were used to estimate the 10-year CV events. Receiver operating characteristic curve analysis was used to determine the optimal discriminator(s) among the central obesity measures in the estimation of a 10-year risk of CV events ≥7.5%, ≥10%, and ≥20% separately.

RESULTS

Among the 5 central obesity indices, conicity index showed the most discriminatory power in estimation of a 10-year CV risk. In men, based on the American College of Cardiology/American Heart Association tool, the areas under the curve (AUCs) were from 0.671 to 0.682 based on the 3 above thresholds, whereas with the Framingham tool, AUCs were from 0.651 to 0.659. In women, all AUCs were >0.7. Our results also showed WHR to be an almost comparable discriminator of CV disease risk in the Iranian study population.

CONCLUSION

Conicity index and WHR had a more discriminatory accuracy for 10-year CV events compared with the other obesity indices.

Do Perceptions of Empowerment Affect Glycemic Control and Self-Care Among Adults with Type 2 Diabetes?

Background:

The Arab adult with T2DM is understudied with less known facts about the perception of empowerment and its relationship with self-care and glycemic control.

Purpose:

The purpose of this study was to determine the extent to which perception of empowerment by Arab adults living with Type 2 Diabetes Mellitus (T2DM) was associated with better glycemic control and self-care management.

Methods:

A cross-sectional descriptive study was led among 300 Arab adults living in Oman with T2DM in an outpatient diabetes clinic. The Diabetes Empowerment Scale (DES), glycosylated haemaglobin (HbA1c) and Body mass index was assessed. The DES was found to be valid and reliable for the population. ANOVA, Regression analysis, and Structural equation modeling was used for analysis.

Results:

The composite score and three subscales of DES were a significant and strong predictor of good glycemic control among Omani adults with T2DM (p<0.001). Age, education, duration of DM, prior DM education program and medications were significantly associated with DES.

Conclusion:

Diabetes nurse educators engaged in the care of adults with T2DM should assess self-empowerment and tailor interventions to increase empowerment for better glycemic control. Patient empowerment plays an essential role in maintaining self-care behaviours and HbA1c.

How effective are antioxidant supplements in obesity and diabetes?

Obesity is a central health issue due to its epidemic prevalence and its association with type 2 diabetes and other comorbidities. Obesity is not just being overweight. It is a metabolic disorder due to the accumulation of excess dietary calories into visceral fat and the release of high concentrations of free fatty acids into various organs. It represents a state of chronic oxidative stress and low-grade inflammation whose intermediary molecules may include leptin, adiponectin and cytokines. It may progress to hyperglycemia, leading to type 2 diabetes. Whether or not dietary antioxidant supplements are useful in the management of obesity and type 2 diabetes is discussed in this review. Only the benefits for obesity and diabetes are examined here. Other health benefits of antioxidants are not considered. There are difficulties in comparing studies in this field because they differ in the time frame, participants' ethnicity, administration of antioxidant supplements, and even in how obesity was measured. However, the literature presents reasonable evidence for marginal benefits of supplementation with zinc, lipoic acid, carnitine, cinnamon, green tea, and possibly vitamin C plus E, although the evidence is much weaker for omega-3 polyunsaturated fatty acids, coenzyme Q10, green coffee, resveratrol, or lycopene. Overall, antioxidant supplements are not a panacea to compensate for a fast-food and video-game way of living, but antioxidant-rich foods are recommended as part of the lifestyle. Such antioxidant foods are commonly available.

Gender variations in waist circumference levels between Aboriginal and non-Aboriginal Australian populations: a systematic review

OBJECTIVES

To compare gender-specific waist circumference (WC) levels of Aboriginal Australians with non-Aboriginal Australians.

METHODS

A systematic search on Medline, PubMed, EMBASE and Google Scholar databases was conducted to identify papers that reported gender-specific waist circumference (WC) estimates of participants from the age of 15 years and above among Aboriginal and non-Aboriginal Australians. Means and their 95% confidence intervals of gender differences in WC, height and weight were recorded or calculated where they were not provided. Gender-specific WC, height and weight mean estimates were pooled and the I(2) statistic was used to test heterogeneity among Aboriginal and non-Aboriginal Australians.

RESULTS

Of 17 selected cross-sectional studies, 9 focused on Aboriginal and 8 on non-Aboriginal Australians. Seven studies reported significantly higher WC estimates among indigenous females than males. On the other hand, non-indigenous males had significantly higher WC levels than females. Males had greater height and weight estimates than females in both groups.

CONCLUSION

Although indigenous women were shorter and had lower weight estimates, they had greater WC levels than indigenous men. This is the first systematic review to assess the gender-specific differences between Aboriginal and non-Aboriginal Australians. The findings of this review warrant more efforts to understand and reduce the high prevalence of central obesity and related chronic diseases among Aboriginal women.

Appropriate cut-off values of waist circumference to predict cardiovascular outcomes: 7-year follow-up in an Iranian population

OBJECTIVE

Due to the lack of compelling evidence for waist circumference (WC) as a cardiovascular disease (CVD) risk factor in many ethnic groups, the need for local research has been expressed by international authorities. This study was undertaken to determine the optimal cut-off points of WC for predicting incident CVD and metabolic syndrome in an Iranian population.

MATERIALS AND METHODS

A total of 6,504 participants from three areas in central Iran were followed over 7 years. Receiver operating characteristics (ROC) and area under the curve (AUC) were used to identify the maximum value of sensitivity and specificity combinations corresponding to the appropriate cut-off points of WC for the detection of the metabolic syndrome and CVD events. The optimal cut-off values were defined as the point at which the value of "sensitivity+specificity-1" reached the maximum value. Finally, Cox proportional hazard modeling was used to determine which cut-off point was better fit in the CVD risk prediction model.

RESULTS

After 394,418 person-years of follow-up, 427 incident primary CVD events (233 men) were identified. Considering CVD, the optimum cut-off points were 99/103.5 cm (men/women) but these had a low sensitivity (AUC: 0.59, 95%CI 0.55-0.63 in both men and women). The second highest values for discriminating CVD were 93/97 cm that resulted in acceptable sensitivity. Regarding the metabolic syndrome, 92.6/97.8 cm were identified as optimum (AUC: 0.67, 95%CI 0.65-0.69 in men and 0.65, 95%CI 0.63-0.67 in women). The best cut-off values that fit in the Cox regression model were 90/97 cm.

CONCLUSION

International recommended WC cut-off values for the Middle East are not appropriate compared to the locally defined cut-off values in Iran.

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.

Incidence of type 2 diabetes in two Indigenous Australian populations: a 6-year follow-up study

OBJECTIVE

To estimate the incidence of type 2 diabetes in two ethnically distinct Indigenous populations in north Queensland, Australia.

DESIGN, SETTING AND PARTICIPANTS

A community-based follow-up study of 1814 Australian Aboriginal and Torres Strait Islander adults from 1999 to 2007. Participants were initially free of diabetes and lived in 19 remote communities in Far North Queensland.

MAIN OUTCOME MEASURES

Fasting blood glucose level; diagnosis of diabetes; blood lipid levels; weight; waist circumference (WC); and blood pressure.

RESULTS

Of the 554 adults who completed the study, 100 developed diabetes over 3412 person-years (py) of follow-up. The incidence of diabetes was similar for Aboriginals (29.7 [95% CI, 20.4-38.4] per 1000 py) and Torres Strait Islanders (29.0 [95% CI, 21.8-38.6] per 1000 py) despite large differences in baseline body mass index (BMI) and WC. The age-standardised incidence for both populations was 30.5 per 1000 py. Obesity defined by WC increased the risk of developing diabetes for Aboriginals (rate ratio [RR], 2.0 [95% CI, 1.1-3.6]) and for Torres Strait Islanders (RR, 6.3 [95% CI, 2.5-16.1]) compared with normal WC. Presence of the metabolic syndrome (MetS) was a strong predictor of incident diabetes (adjusted hazard ratio, 2.4 [95% CI, 1.6-3.7]). For both groups, waist-to-hip ratio and the presence of the MetS better predicted diabetes than WC or BMI.

CONCLUSIONS

The incidence of diabetes in these Indigenous Australians is nearly four times higher than for the non-Indigenous population and 50% higher than the incidence reported 10 years ago in Australian Aboriginals. Currently used BMI cut-off points are not appropriate for Indigenous Australians to predict diabetes.

Performance of body mass index in predicting diabetes and hypertension in the Eastern Province of Saudi Arabia

BACKGROUND AND OBJECTIVES

Body mass index (BMI) is the most widely used measure to define obesity and predict its complications, such as diabetes and hypertension, but its accuracy and usefulness in Saudi subjects is unknown. This study aimed to assess the validity of standard BMI cut-point values in the Saudi population.

SUBJECTS AND METHODS

197 681 adults participated in a cross-sectional study to detect diabetes and hypertension in the Saudi Eastern province in 2004/2005, with blood pressure, fasting blood sugar, height and weight measurements taken. Sensitivities, specificities, areas under the curves, predictive values, likelihood ratios, false positive, false negatives and total misclassification ratios were calculated for various BMI values determined from receiver operating characteristic (ROC) curves. The significance of the association between risk factors and BMI was assessed using regression analysis.

RESULTS

For the definition of overweight, ROC curve analysis suggested optimal BMI cut-offs of 28.50 to 29.50 in men and 30.50 to 31.50 in women, but the levels of sensitivity and specificity were too low to be of clinical value and the overall misclassification was unacceptably high across all the selected BMI values (>0.80). The relationship between BMI and the presence of diabetes and/or hypertension was not improved when a BMI of 25 was used. Using regression analyses, the odds ratios for hypertension and/or diabetes increased significantly from BMI values as low as 21-23 with no improvement in the diagnostic performance of BMI at these cutoffs.

CONCLUSION

In Saudi population, there is an increased risk of diabetes and hypertension relative to BMI, starting at a BMI as low as 21 but overall there is no cutoff BMI level with high predictive value for the development of these chronic diseases, including the WHO definition of obesity at BMI of 30.