Optimal Waist-to-Height Ratio Values for Cardiometabolic Risk Screening in an Ethnically Diverse Sample of South African Urban and Rural School Boys and Girls

Background

The proposed waist-to-height ratio (WHtR) cut-off of 0.5 is less optimal for cardiometabolic risk screening in children in many settings. The purpose of this study was to determine the optimal WHtR for children from South Africa, and investigate variations by gender, ethnicity and residence in the achieved value.

Methods

Metabolic syndrome (MetS) components were measured in 1272 randomly selected learners, aged 10–16 years, comprising of 446 black Africans, 696 mixed-ancestry and 130 Caucasians. The Youden’s index and the closest-top-left (CTL) point approaches were used to derive WHtR cut-offs for diagnosing any two MetS components, excluding the waist circumference.

Results

The two approaches yielded similar cut-off in girls, 0.465 (sensitivity 50.0, specificity 69.5), but two different values in boys, 0.455 (42.9, 88.4) and 0.425 (60.3, 67.7) based on the Youden’s index and the CTL point, respectively. Furthermore, WHtR cut-off values derived differed substantially amongst the regions and ethnic groups investigated, whereby the highest cut-off was observed in semi-rural and white children, respectively, Youden’s index0.505 (31.6, 87.1) and CTL point 0.475 (44.4, 75.9).

Conclusion

The WHtR cut-off of 0.5 is less accurate for screening cardiovascular risk in South African children. The optimal value in this setting is likely gender and ethnicity-specific and sensitive to urbanization.     

Comparison of Body Mass Index (BMI), Body Adiposity Index (BAI), Waist Circumference (WC), Waist-To-Hip Ratio (WHR) and Waist-To-Height Ratio (WHtR) as Predictors of Cardiovascular Disease Risk Factors in an Adult Population in Singapore

Background

Excess adiposity is associated with cardiovascular disease (CVD) risk factors such as hypertension, diabetes mellitus and dyslipidemia. Amongst the various measures of adiposity, the best one to help predict these risk factors remains contentious. A novel index of adiposity, the Body Adiposity Index (BAI) was proposed in 2011, and has not been extensively studied in all populations. Therefore, the purpose of this study is to compare the relationship between Body Mass Index (BMI), Waist Circumference (WC), Waist-to-Hip Ratio (WHR), Waist-to-Height Ratio (WHtR), Body Adiposity Index (BAI) and CVD risk factors in the local adult population.

Methods and Findings

This is a cross sectional study involving 1,891 subjects (Chinese 59.1% Malay 22.2%, Indian 18.7%), aged 21–74 years, based on an employee health screening (2012) undertaken at a hospital in Singapore. Anthropometric indices and CVD risk factor variables were measured, and Spearman correlation, Receiver Operating Characteristic (ROC) curves and multiple logistic regressions were used. BAI consistently had the lower correlation, area under ROC and odd ratio values when compared with BMI, WC and WHtR, although differences were often small with overlapping 95% confidence intervals. After adjusting for BMI, BAI did not further increase the odds of CVD risk factors, unlike WC and WHtR (for all except hypertension and low high density lipoprotein cholesterol). When subjects with the various CVD risk factors were grouped according to established cut-offs, a BMI of ≥23.0 kg/m² and/or WHtR ≥0.5 identified the highest proportion for all the CVD risk factors in both genders, even higher than a combination of BMI and WC.

Conclusions

BAI may function as a measure of overall adiposity but it is unlikely to be better than BMI. A combination of BMI and WHtR could have the best clinical utility in identifying patients with CVD risk factors in an adult population in Singapore.     

代谢综合征患者肥胖和脂质代谢参数的特征及其诊断价值

目的:比较代谢综合征(MetS)患者不同肥胖和脂质代谢参数的特征和其对疾病的诊断价值。方法:回顾性分析2016年1月至2018年12月在我院就诊的MetS患者和健康体检者,比较其体重指数(Body Mass Index, BMI)、腰高比(Waist-to-Height Ratio,WHt R)、甘油三酯/高密度脂蛋白胆固醇(TG/HDL-C)、脂肪蓄积指数(Lipid accumulation product, LAP)和内脏脂肪指数(Visceral adiposity index,VAI)的差异及不同代谢因素分组患者上述参数差异。采用ROC曲线评价不同肥胖和脂质代谢参数对MetS的诊断价值。结果:与健康组相比,MetS组无论男性还是女性患者BMI、WC、WHt R、血压、FPG、TG、TG/HDL-C、LAP和VAI均明显升高,而HDL-C显著降低(P0.05)。随着MetS特征个数的增加,MetS组患者的BMI、WHt R、TG/HDL-C、LAP和VAI均呈现显著增加趋势(P0.05)。上述五个诊断MetS的ROC曲线中都是LAP的AUC最大,男性AUC为0.896,敏感度为0.75,特异度为0.84。女性LAP的AUC为0.874,最佳诊断切点为31.05,此时的敏感度为0.74,特异度为0.92。结论:LAP对代谢综合征的诊断效能最高,男性LAP大于26.36、女性LAP大于31.05有助于诊断代谢综合征患者。     

Receiver operating characteristic curve analysis of BMI in assessing obesity among adult Bengalee males in India

The present study attempted to understand the appropriateness of different body mass index (BMI) cut-off points in assessing obesity. Four hundred thirty adult Bengalee males with mean age 36.48 +/- 12.23 years (mean +/- SD) from West Bengal, India were studied. Height, weight and percent body fat were measured and BMI was derived following standard equation. Receiver operating characteristic (ROC) curve analysis demonstrated low sensitivity and high specificity of international (> or = 30 kg/m2) and proposed (> or = 25 kg/m2) BMI cut-off points in identifying individuals with obesity. Furthermore, these international and proposed BMI cut-off points also found to be in substantial misclassification to assess obesity as much as 32.09% and 17.44% respectively. However, based on ROC curve analysis, a BMI cut-off point of > or = 24 kg/m2 revealed optimal sensitivity (83.66%) and specificity (90.61%) and as well as less misclassification (11.86%) in assessing obesity among the adult Bengalee males. The present study accentuated that the international and proposed BMI cut-off points so far might not be appropriate in assessing obesity and on the other hand, lower BMI cut-off point (> or = 24 kg/m2) has relatively high sensitivity and specificity in assessing obesity as well. Therefore, the present study envisages the requirement of further lowering down of BMI cut-off point in assessing excess body fat in adult Bengalee males.     

Cardiovascular risk management of hypertension and hypercholesterolaemia in the Netherlands: from unifactorial to multifactorial approach

About 30?years ago, the first Dutch unifactorial guidelines on hypertension and hypercholesterolaemia were developed. These guidelines have been revised several times, often after publication of landmark studies on new generations of drugs. In 1978, cut-off points for pharmacological treatment of hypertension were based on diastolic blood pressure values ≥115?mmHg, and in 2000 they were lowered to >100?mmHg. From 1997 onwards, cut-off points for systolic blood pressure values >180?mmHg were introduced, which became leading. In 1987, cut-offs for hypercholesterolaemia of ≥8?mmol/l were set and from 2006 pharmacological treatment was based on a total/HDL cholesterol ratio >8. Around 2000, treatment decisions for hypertension and/or hypercholesterolaemia were no longer based on high levels of individual risk factors, but on a multifactorial approach based on total risk of cardiovascular diseases (CVD), determined by a risk function. In the 2006 multidisciplinary guideline on cardiovascular risk management, the Framingham risk tables were replaced by European SCORE risk charts. A cut-off point of 10% CVD mortality was set in the Netherlands. In 2011, this cut-off point changed to 20% fatal plus nonfatal CVD risk. Nowadays, 'the lower the risk factors, the lower the absolute risk' is the leading paradigm in CVD prevention.     

Age trends in prevalence of cardiovascular risk factors in Roma minority population of Croatia

The Roma (Gypsy) are the largest European minority population characterized by poverty, social exclusion as well as by numerous life-style and cultural specificities, which all could have an adverse impact on their cardiovascular health. This study assesses the prevalence of cardiovascular diseases (CVD) risk factors in community-based sample of 430 adult Roma, living in rural area of Croatia, by providing the actual and age-adjusted estimates using the European standard population. The most prominent classical CVD risk phenotypes (blood pressure, obesity, smoking, glucose and lipid profile) were selected, and the standard risk cut-offs were applied. The study has shown that compared to general population of Croatia, the Roma population bears a high CVD risk factors load related to smoking and high glucose level. The CVD risk factors prevalence in Roma also showed important sex and age patterns, the most imposing of which are the findings of higher prevalence of CVD risks in women (especially obesity and triglyceride levels) and the trend of higher body mass index (BMI) level in younger age group (18–34 years) which both stand in contrast to the trends characterizing the general population of Croatia. These findings are complemented by the trend of decreased risk in the oldest age group (65+ years) for all investigated CVD risk factors (with exception of triglycerides level) compared to the 50–64 age group. We conclude that the age and sex CVD risks pattern point to the health transition of this rural Roma population. As we expect the proportion of CVD in the Roma minority of Croatia to increase in the future along with further modernization of their lifestyle, the CVD prevention measures in this population are urgent and should be primarily targeted at women and at the younger segment of this population.     

Simple anthropometric indices in relation to cardiovascular risk factors in Chinese type 2 diabetic patients

To determine which is the best anthropometric index among body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHtR) in type 2 diabetic patients, we examined the relationship between these indices and cardiovascular risk factors using partial correlation analysis, chi-square test, logistic regression analysis and Receiver Operator Characteristic (ROC) curves. Partial correlation analysis showed that among the 4 obesity indices, WHtR had the highest r values for all the cardiovascular risk factors in both sexes, followed by WC. Chi-square analysis which revealed that an increased WHtR was more strongly associated with hypertension, hypertriglyceridemia (high TG) and low high-density lipoprotein cholesterol (HDL-C) than the other indices. Logistic regression analysis showed that, after controlling for age, the hypertension, high TG and low HDL-C odds ratios of WHtR > or = 0.5 were 2.56 (95% CI: 1.24, 5.29), 2.87 (95% CI: 1.43, 5.78), 2.59 (95% CI: 1.03, 6.59) in men and 3.75 (95% CI: 1.75, 8.05), 3.21 (95% CI: 1.52, 6.79), 3.62 (95% CI: 1.43, 9.21) in women, respectively. In ROC analysis, the areas under curve of WHtR were the largest for at least one risk factor in both men and women. These results indicated that WHtR had a higher correlation with cardiovascular risk factors than WC, WHR or BMI in newly diagnosed type 2 diabetes. We proposed the measurement of WHtR as a screening tool for cardiovascular risk factors in this population.     

Phenotypical characterisation of the isolated norfolk island population focusing on epidemiological indicators of cardiovascular disease

OBJECTIVES: Only 193 people from Pitcairn Island, all descended from 9 'Bounty' mutineers and 12 Tahitian women, moved to the uninhabited Norfolk Island in 1856. Our objective was to assess the population of Norfolk Island, several thousand km off the eastern coast of Australia, as a genetic isolate of potential use for cardiovascular disease (CVD) gene mapping. METHODS: A total of 602 participants, approximately two thirds of the island's present adult population, were characterized for a panel of CVD risk factors. Statistical power and heritability were calculated. RESULTS: Norfolk Islander's possess an increased prevalence of hypertension, obesity and multiple CVD risk factors when compared to outbred Caucasian populations. 64% of the study participants were descendents of the island's original founder population. Triglycerides, cholesterol, and blood pressures all had heritabilities above 0.2. CONCLUSIONS: The Norfolk Island population is a potentially useful genetic isolate for gene mapping studies aimed at identifying CVD risk factor quantitative trait loci (QTL).     

Anthropomorphic measurements that include central fat distribution are more closely related with key risk factors than BMI in CKD stage 3

Background

Body Mass Index (BMI) as a marker of obesity is an established risk factor for chronic kidney disease (CKD) and cardiovascular disease (CVD). However, BMI can overestimate obesity. Anthropomorphic measurements that include central fat deposition are emerging as a more important risk factor. We studied BMI, waist circumference (WC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR) and conicity index (CI) in a cohort of patients with CKD stage 3 and compared the associations with other known risk factors for CKD progression and CVD.

Methods

1740 patients with CKD stage 3 were recruited from primary care for the Renal Risk in Derby study. Each participant underwent clinical assessment, including anthropomorphic measurements and pulse wave velocity (PWV), as well as urine and serum biochemistry tests.

Results

The mean age of the cohort was 72.9±9 years with 60% females. The mean eGFR was 52.5±10.4 ml/min/1.73 m² and 16.9% of the cohort had diabetes. With the cohort divided into normal and increased risk of morbidity and mortality using each anthropomorphic measurement, those measurements that included increased central fat distribution were significantly associated with more risk factors for CKD progression and CVD than increased BMI. Univariable analysis demonstrated central fat distribution was correlated with more risk factors than BMI. Subgroup analyses using recognised BMI cut-offs to define obesity and quartiles of WHR and CI demonstrated that increasing central fat distribution was significantly associated with more CKD and CVD risk factors than increasing BMI.

Conclusion

Anthropomorphic measurements that include a measure of central fat deposition are related to more key risk factors in CKD stage 3 patients than BMI. Central fat deposition may be of greater importance as a risk factor in CKD than BMI and reliance on BMI alone may therefore underestimate the associated risk.     

Body configuration as a predictor of mortality: comparison of five anthropometric measures in a 12 year follow-up of the Norwegian HUNT 2 study

Background

Distribution of body fat is more important than the amount of fat as a prognostic factor for life expectancy. Despite that, body mass index (BMI) still holds its status as the most used indicator of obesity in clinical work.

Methods

We assessed the association of five different anthropometric measures with mortality in general and cardiovascular disease (CVD) mortality in particular using Cox proportional hazards models. Predictive properties were compared by computing integrated discrimination improvement and net reclassification improvement for two different prediction models. The measures studied were BMI, waist circumference, hip circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). The study population was a prospective cohort of 62,223 Norwegians, age 20–79, followed up for mortality from 1995–1997 to the end of 2008 (mean follow-up 12.0 years) in the Nord-Trøndelag Health Study (HUNT 2).

Results

After adjusting for age, smoking and physical activity WHR and WHtR were found to be the strongest predictors of death. Hazard ratios (HRs) for CVD mortality per increase in WHR of one standard deviation were 1.23 for men and 1.27 for women. For WHtR, these HRs were 1.24 for men and 1.23 for women. WHR offered the greatest integrated discrimination improvement to the prediction models studied, followed by WHtR and waist circumference. Hip circumference was in strong inverse association with mortality when adjusting for waist circumference. In all analyses, BMI had weaker association with mortality than three of the other four measures studied.

Conclusions

Our study adds further knowledge to the evidence that BMI is not the most appropriate measure of obesity in everyday clinical practice. WHR can reliably be measured and is as easy to calculate as BMI and is currently better documented than WHtR. It appears reasonable to recommend WHR as the primary measure of body composition and obesity.     

Obesity in the Elderly and Its Relationship with Cardiovascular Risk Factors in Taiwan**

Objectives: The obese elderly are at increased risk of mortality, morbidity, and functional disability. In this study, we examined the prevalence of obesity and relationship between various anthropometric indices (AI) and cardiovascular disease (CVD) risk factors in the elderly. Research Methods and Procedures: A stratified multistage clustered sampling scheme was used in the Elderly Nutrition and Health Survey in Taiwan during 1999 to 2000. 2432 non‐institutionalized subjects (age, 72.8 ± 9.4 years; BMI, 23.6 ± 6.4 kg/m²) were recruited. The receiver operating characteristic analysis was used to compare predictive validity of CVD risk factors among various AI, including BMI, waist circumference (WC), and waist‐to‐hip ratio (WHR). Results: The prevalence of obesity was 29.0% in men and 36.8% in women by obesity criteria for Asians (BMI ≥ 25 kg/m²) and 13.3% in men and 21.0% in women by the Taiwanese definition (BMI ≥ 27 kg/m²). Odds ratios of acquiring various CVD risk factors increased significantly with increment of WC, WHR, and BMI. The areas under the curve predicting metabolic syndrome were all <0.8. The cut‐off values of WC corresponding to the highest sensitivity and the highest specificity in predicting various CVD risk factors were 86.2–88.0 cm in men and 82.0–84.0 cm in women, respectively. Discussion: Obesity was prevalent in the Taiwanese elderly. WC was related to CVD risk factors to a greater extent than BMI and WHR. However, none of them alone was a good screening tool for CVD risk factors. Therefore, how to apply AI prudently to screen elderly for CVD risk factors needs further research.     

Waist circumference and BMI cut-off based on 10-year cardiovascular risk: evidence for "central pre-obesity"

Objective: The objective was to assess the waist circumference (WC) cut‐off point that best identifies a level of 10‐year cardiovascular disease (CVD) risk with optimal balance of sensitivity and specificity in Chinese subjects according to their predicted 10‐year CVD risk. Research Methods and Procedures: A community‐based cross‐sectional observational study involving 14,919 Hong Kong Chinese subjects. The 10‐year CVD risk based on various prediction models was calculated. The projected WC cut‐off points were then determined. Results: There were 4837 (32.4%) men and 10,082 (67.6%) women (mean age ± standard deviation, 47.3 ± 13.5 years; age range, 18 to 93 years; median age, 45.0 years). The mean optimal WC or BMI predicting a 15% to 30% 10‐year CVD risk were 83 to 88 cm and 25 kg/m² for men, and 76 cm and 23 kg/m² for women, respectively. With WC ≥90 cm in men and ≥80 cm in women, the likelihood ratio at various WC cut‐off points to develop a ≥20% 10‐year CVD risk is 1.5 to 2.0 in men and 3.0 in women. The likelihood ratio was 1.5 in men with WC at 84 cm and in women at 70 cm. Discussion: Our results agree with the present guidelines on the definition of general and central obesity in Asia‐Pacific regions. We propose the creation of an intermediate state of high WC, the “central pre‐obesity” for Chinese men with WC ≥84 to 90 cm (≥33 to 36 inches) and women with WC ≥74 to 80 cm (≥29 to 32 inches). People with central pre‐obesity, similar to those with overweight (BMI ≥23 to 25 kg/m²), already have an increased risk of co‐morbidities.     

Trends in Cardiovascular Disease Risk Factors in People with and without Diabetes Mellitus: A Middle Eastern Cohort Study

Aims/Hypothesis

To investigate secular trends in cardiovascular disease (CVD) risk factors during a decade of follow-up in a Middle Eastern cohort, and to compare observed trends between diabetic and non-diabetic populations.

Methods

In a population of 6181 participants (2622 males and 3559 females), diabetes status and CVD risk factors were evaluated in 4 study phases from 1999–2011. 1045 subjects had type 2 diabetes mellitus at baseline and 5136 participants were diabetes-free. To examine the trends of CVD risk factors, generalized estimation equation models were constructed. The interaction between the diabetes status and each phase of the study was checked in a separate model.

Results

During the follow-up period diabetic females significantly gained better control of their blood pressure, serum low density lipoprotein cholesterol and general and central obesity measures compared to non-diabetic counterparts, although 60% of them had high BP and 64% had high serum LDL-C levels till the end of the study. Diabetic males however, experienced significantly better control on their serum LDL-C and general and central obesity measures compared to their non-diabetic controls; but 24% of them were still smoker, 63% had high BP and 60% had high serum LDL-C levels at the end of the follow-up (all Ps _interaction <0.05). Use of lipid-lowering and antihypertensive medications increased consistently in both diabetic and non-diabetic populations.

Conclusions/Interpretation

Although CVD risk factors have been controlled to some extent among diabetic population in Iran, still high numbers of people with diabetes have uncontrolled CVD risk factors that prompt more attention.     

Body mass index and the risk of head and neck cancer in the Chinese population

ObjectiveTo investigate potential associations between body mass index (BMI) and head and neck cancer (HNC) risk in an East Asian population.MethodsWe conducted a hospital-based multicenter case-control study in East Asia including 921 cases and 806 controls. We estimated the odds ratios (ORs) and 95% confidence intervals (95% CI) for HNC risks by using logistic regression, adjusting on potential confounders.ResultsCompared to normal BMI at interview (18.5–<25 kg/m²), being underweight (BMI < 18.5 kg/m²) was associated with a higher HNC risk (OR = 2.71, 95% CI 1.40–5.26). Additionally, obesity (BMI > 30 kg/m²) was associated with a lower HNC risk (OR = 0.30, 95% CI 0.16–0.57). Being underweight at age 20 was also associated with an increased risk of HNC. However, being underweight at 5 years or 2 years before interview was not associated with a higher risk of HNC.ConclusionWe observed an inverse association between BMI and HNC risk, which is consistent with previous studies in other geographic regions. Being underweight at age 20 was also associated with a higher risk of HNC, suggesting that reverse causality was not the main source of the association.     

Metabolically Healthy Obesity and the Risk of Cardiovascular Disease in the Elderly Population

BackgroundWhether being metabolically healthy obese (MHO)—defined by the presence of obesity in the absence of metabolic syndrome—is associated with subsequent cardiovascular disease (CVD) remains unclear and may depend on the participants’ age. We examined the association of being MHO with CVD risk in the elderly.ConclusionsIn our elderly population, we found that the presence of obesity without metabolic syndrome did not confer a higher CVD risk. However, metabolic syndrome was strongly associated with CVD risk, and was associated with an increased risk in all BMI categories. Therefore, preventive interventions targeting cardiometabolic risk factors could be considered in elderly, regardless of weight status.     

Comparison of measures of adiposity in identifying cardiovascular disease risk among Ethiopian adults

We sought to determine which measures of adiposity can predict cardiovascular disease (CVD) risk and to evaluate the extent to which overall and abdominal adiposity are associated with cardiometabolic risk factors among working adults in Ethiopia. This was a cross-sectional study of 1,853 individuals (1,125 men, 728 women) in Addis Ababa, Ethiopia. The World Health Organization STEPwise approach was used to collect sociodemographic data, anthropometric measurements, and blood samples among study subjects. Fasting blood glucose (FBG) and lipid concentrations were measured using standard approaches. Spearman's rank correlation, receiver operating characteristic (ROC) curves, and logistic regression were employed to determine the association and predictive ability (with respect to CVD risk factors) of four measures of adiposity: BMI, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). Overall, FBG is best associated with WHtR in men and WC in women. Systolic blood pressure (SBP) is most strongly associated with BMI in men, but with WC in women. Compared to those with low BMI and low WC, the risk of having CVD is the highest for those with high BMI and high WC and those with high WC and low BMI. Review of ROC curves indicated that WC is the best predictor of CVD risk among study subjects. Findings from our study underscore the feasibility and face validity of using simple measures of central and overall adiposity in identifying CVD risk in resource-poor settings.     

Familial Risk of Overweight and Obesity in the Canadian Population using the WHO/NIH Criteria

Objective: To determine the familial risk of overweight and obesity in Canada. Research Methods and Procedures: The sample was comprised of 15,245 participants from 6377 families of the Canada Fitness Survey. The risk of overweight and obesity among spouses and first‐degree relatives of individuals classified as underweight, normal weight, pre‐obese, or obese (Class I and II) according to the WHO/NIH guidelines for body mass index (BMI) was determined using standardized risk ratios. Results: Spouses and first‐degree relatives of underweight individuals have a lower risk of overweight and obesity than the general population. On the other hand, the risk of Class I and Class II obesity (BMI 35 to 39.9 kg/m²) in relatives of Class I obese (BMI 30 to 34.9 kg/m²) individuals was 1.84 (95% CI: 1.27, 2.37) and 1.97 (95% CI: 0.67, 3.25), respectively, in spouses, and 1.44 (95% CI:1.10, 1.78) and 2.05 (95% CI: 1.37, 2.73), respectively in first‐degree relatives. Further, the risk of Class II obesity in spouses and first‐degree relatives of Class II obese individuals was 2.59 (95% CI: ?0.91, 6.09) and 7.07 (95% CI: 1.48, 12.66) times the general population risk, respectively. Discussion: There is significant familial risk of overweight and obesity in the Canadian population using the BMI as an indicator. Comparison of risks among spouses and first‐degree relatives suggests that genetic factors may play a role in obesity at more extreme levels (Class II obese) more so than in moderate obesity.     

Combination of BMI and Waist Circumference for Identifying Cardiovascular Risk Factors in Whites

Objective: BMI (kilograms per meters squared) and waist circumference (WC) (measured in centimeters) are each associated with the risk of developing cardiovascular disease (CVD). Therefore, a combination of the two may be more effective in identifying subjects at risk than either alone. The present study sought to identify the combination of BMI and WC that has the strongest association with CVD risk factors in whites. Research Methods and Procedures: Subjects were 8712 white men and women from the Third National Health and Nutrition Examination Survey. The optimal combination of BMI and WC was developed using logistic regression models with BMI and WC as predictors and CVD risk factors as outcomes. The combined measure of BMI and WC using current cut‐off points was also examined. Sensitivity, specificity, and receiver operating characteristics curves were compared between the combined measures and BMI alone. Results: For white men, the optimal combination of BMI and WC for identifying CVD risk factors was 0.68 × BMI + 0.32 × WC. This combination generated a score that better estimated the odds of having CVD risk factors than either alone. For white women, WC alone largely determined the likelihood of having CVD risks. The combination of BMI and WC using current cut‐off points may provide an improved measure of CVD risk. Combined measures showed a higher sensitivity or a shorter distance in receiver operating characteristic curves in the identification of CVD risk factors. Discussion: Combined measures of BMI and WC may provide a higher overall test performance for CVD risk factors and may be useful in some ethnic groups as an improved means of screening subjects for further evaluation in the clinical setting.     

Age-Dependent Influence of Gender on the Association Between Obesity and a Cluster of Cardiometabolic Risk Factors

BackgroundObesity is a main risk factor in metabolic syndrome. Gender is known to influence the risk of obesity and other cardiovascular risk factors. However, it remains to be determined whether there is a gender-specific difference in the relationship between obesity and accumulation of other cardiometabolic risk factors such as hypertension, dyslipidemia, and diabetes.ObjectiveThe aim of this study was to determine whether the association between obesity and a cluster of other cardiometabolic risk factors is modified by gender.MethodsThe subjects were 17,791 Japanese men and women who were divided into younger (35–40 years) and older (60–70 years) age groups. The relationships between obesity (body mass index [BMI] ≥25 kg/m² or waist-to-height ratio [WHtR] ≥0.5) and multiple cardiometabolic risk factors (≥2 of the risk factors of high blood pressure, dyslipidema, and hyperglycemia) were compared between men and women in each age group.ResultsIn the younger group, the crude odds ratios (ORs) for multiple cardiometabolic risk factors in obese versus nonobese subjects were significantly higher in women than in men (BMI: 6.23 [range, 5.53–7.02] in men vs 16.63 [range, 12.37–22.37] in women, P < 0.01; WHtR: 6.04 [range, 5.36–6.81] in men vs 9.77 [range, 7.14–13.37] in women, P < 0.01), whereas this difference was not found in the older group (BMI: 3.03 [range, 2.69–3.42] in men vs 2.92 [range, 2.33–3.67] in women P = 0.076; WHtR: 3.11 [range, 2.78–3.47] in men vs 2.50 [range, 2.02–3.09] in women, P < 0.05). On multivariate logistic regression analysis, the ORs for multiple cardiometabolic risk factors after adjusting for age, smoking, alcohol consumption, and regular exercise in subjects with versus subjects without a large waist circumference tended to be higher in women than in men in the younger group but not in the older group. The ORs of the interaction term consisting of gender and each adiposity index for multiple cardiometabolic risk factors were significantly higher than a reference level of 1.00 in the younger group (BMI: 2.68 [range, 1.95–3.69], P < 0.01; WHtR: 1.62 [range, 1.16–2.27], P < 0.01) but not in the older group (BMI: 0.95 [range, 0.74–1.23], P = 0.712; WHtR: 0.80 [range, 0.63–1.02], P = 0.066).ConclusionThe results suggest that the association between obesity and a cluster of cardiometabolic risk factors is stronger in women than in men, and this gender-specific difference exists in younger (35–40 years) but not in older (60–70 years) individuals.     

Association of Body Mass Index with All-Cause and Cardiovascular Disease Mortality in the Elderly

Objectives

To evaluate the associations of body mass index (BMI) with all-cause, cardiovascular disease (CVD), and expanded CVD mortality in the elderly.

Design

Observational cohort study.

Setting

Annual physical examination program for the elderly from 2006 to 2010.

Participants

We included 77,541 Taipei residents aged ≥65 years (39,365 men and 38,176 women).

Measurements

BMI was categorized as underweight (BMI<18.5), normal weight (18.5≤BMI<25), overweight (25≤BMI<30), grade 1 obesity (30≤BMI<35), or grade 2–3 obesity (BMI≥35). Mortality was ascertained by national death files.

Results

Underweight (hazard ratios [HRs] of all-cause, CVD, and expanded CVD mortality: 1.92, 1.74, and 1.77, respectively), grade 2–3 obesity (HRs: 1.59, 2.36, and 2.22, respectively), older age, male sex, smoking, and high fasting blood sugar were significant predictors of mortality. Meanwhile, being married/cohabitating, higher education, alcohol consumption, more regular exercise, and high total cholesterol were inversely associated with mortality. Multivariate stratified subgroup analyses verified smokers (HRs of all-cause, CVD, and expanded CVD mortality: 3.25, 10.71, and 7.86, respectively, for grade 2–3 obesity), the high triglyceride group (HRs: 5.82, 10.99, and 14.22, respectively for underweight), and patients with 3–4 factors related to metabolic syndrome (HRs: 4.86, 12.72, and 11.42, respectively, for underweight) were associated with mortality.

Conclusion

The associations of BMI with all-cause, CVD, expanded CVD mortality in the elderly are represented by U-shaped curves, suggesting unilateral promotions or interventions in weight reduction in the elderly may be inappropriate. Heterogeneous effects of grades 1 and 2–3 obesity on mortality were observed and should be treated as different levels of obesity.