Race-ethnicity-specific waist circumference cutoffs for identifying cardiovascular disease risk factors

BACKGROUND: Waist circumferences (WCs) in white men and women that represent a risk of cardiovascular disease (CVD) equivalent to that of body mass indexes (BMIs; in kg/m2) of 25 and 30 have been identified. However, WC cutoffs for other race-ethnicity groups remain unknown. OBJECTIVE: The objective was to determine WC cutoffs for CVD risk in non-Hispanic blacks (blacks), Mexican Americans (MA), and non-Hispanic whites (whites). DESIGN: Data from 10,969 participants in the third National Health and Nutrition Examination Survey (1988-1994) were analyzed. The presence of CVD risk factors was the main outcome. Sex- and race-ethnicity-specific WC cutoffs were determined with logistic regression models by linking WC cutoffs with equivalent CVD risk based on BMI cutoffs for overweight and obesity. WC cutoffs for metabolic syndrome risk factors were similarly calculated. RESULTS: Correlations between WC and lipid profiles, blood pressure, and glucose were significantly higher than those between BMI and these same variables in all groups. The WC cutoffs were approximately 5-6 cm greater for white than for black men at BMIs between 25 and 40, and those for MA were intermediate. In women, few differences in WC cutoffs were observed between the groups. Simplified WC cutoffs corresponding to BMIs of 25 and 30, largely independent of age, for the 3 race-ethnicity groups were 89 and 101 cm for men and 83 and 94 cm for women. Minimal distances in receiver operating characteristic curves tended to be shorter when WC cutoffs rather than BMI cutoffs were used. CONCLUSIONS: WC is a better indicator of CVD risk than is BMI in the 3 race-ethnicity groups studied. The proposed WC cutoffs are more sensitive than are BMI cutoffs in predicting CVD risk.     

Non-obese (body mass index < 25 kg/m2) Asian Indians with normal waist circumference have high cardiovascular risk

OBJECTIVE: Although the prevalence of obesity is not high in Asian Indians, increased prevalence rates of metabolic perturbations and cardiovascular risk factors have been reported. In this study, we evaluated body mass index (BMI), anthropometric measurements, and body fat profiles of obese and non-obese subjects and correlated those values with cardiovascular risk factors. METHODS: This cross-sectional study involved 639 subjects (170 men and 469 women) from low socioeconomic stratum residing in urban slums of New Delhi. Non-obese subjects were categorized into quartiles of percentage of body fat (%BF) and waist circumference (WC). Using logistic regression analysis, the odds ratios (ORs) and 95% confidence intervals (CIs) for the occurrence of cardiovascular risk factors (diabetes mellitus [DM], hypertension, hypercholesterolemia, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, and high levels of low-density lipoprotein cholesterol) were computed with first quartile in the non-obese group as the reference category for the following five categories: %BF and WC quartiles in the non-obese group and obese group (BMI > or = 25 kg/m(2)). RESULTS: In the non-obese group, approximately 66% of men and 88% of women had at least one risk factor. In non-obese women, significantly high ORs and 95% CIs were found for hypertension (3.2, 1.4-7.2), DM (2.8, 1.2-6.3), and hypertriglyceridemia (3.9, 1.9-8.3) in the upper quartiles of %BF, and significantly high OR (95% CIs) was observed for hypertriglyceridemia (3.9, 1.4-10.8) in non-obese men. Among non-obese men, significantly high OR (95% CIs) was found for hypertriglyceridemia (3.2, 1.0-10.3); among non-obese women, significantly high ORs (95% CIs) were observed for hypertension (2.5, 1.1-5.8) and hypertriglyceridemia (2.5, 1.2-5.2) in the normal range of WC (70-80 cm). CONCLUSION: The study showed that Asian Indians have excess cardiovascular risk at BMI and WC values considered "normal." These data suggested that definitions of "normal" ranges of BMI and WC need to be revised for Asian Indians.     

Obesity misclassification and the metabolic syndrome in adults with functional mobility impairments: Nutrition Examination Survey 2003–2006

ObjectivesThe purpose of this study was to estimate the degree of obesity misclassification between body mass index (BMI) and body fat percentage in adults with functional mobility impairment, and to determine cardiometabolic risk profiles.MethodsData from the combined 2003–2006 National Health and Nutrition Examination Survey (NHANES) were incorporated. The representative sample included 852 individuals, aged 20–85 years, reporting at least one major physical limitation related to mobility or lower body function, and 4724 individuals reporting no impairments. Body mass index, percent body fat (%BF) as determined by dual energy X-ray absorptiometry (DXA), objectively measured sedentary behavior and activity, and markers of cardiometabolic risk were compared between adults with and without functional mobility impairments. Among functional mobility impaired individuals, sensitivity, specificity, and receiver operating characteristic curves were used to evaluate the performance of BMI as a continuous variable, as well as various BMI thresholds to detect obesity defined by sex-specific %BF cutoffs.ResultsAdults with functional mobility impairments were older, had larger waist circumferences (WC), had greater prevalence of obesity according to BMI and %BF, were more sedentary, had less physical activity, and had higher overall cardiometabolic risk. The standard BMI cutoff for obesity had excellent specificity in both men (100%) and women (98.4%) with functional mobility impairment, but sensitivity was poor (< 55%). Whereas approximately 36% and 43% of impaired men and women fell into the obese BMI category, over 80% of men and women were obese according to %BF. Individuals with high %BF who were misclassified as not obese, according to BMI, had a significantly higher prevalence of the metabolic syndrome (17.6%) compared to subjects with normal BMI and low %BF (2.1%).ConclusionsObesity misclassification and cardiometabolic risk are prevalent among individuals with functional mobility impairments, and thus diagnostic screening for obesity should be modified to account for %BF and/or waist circumference. Behavioral interventions to decrease sedentary behavior, increase activity, and reduce abdominal obesity are warranted.     

Body composition interpretation. Contributions of the fat-free mass index and the body fat mass index

OBJECTIVE: Low and high body mass index (BMI) values have been shown to increase health risks and mortality and result in variations in fat-free mass (FFM) and body fat mass (BF). Currently, there are no published ranges for a fat-free mass index (FFMI; kg/m(2)), a body fat mass index (BFMI; kg/m(2)), and percentage of body fat (%BF). The purpose of this population study was to determine predicted FFMI and BFMI values in subjects with low, normal, overweight, and obese BMI. METHODS: FFM and BF were determined in 2986 healthy white men and 2649 white women, age 15 to 98 y, by a previously validated 50-kHz bioelectrical impedance analysis equation. FFMI, BFMI, and %BF were calculated. RESULTS: FFMI values were 16.7 to 19.8 kg/m(2) for men and 14.6 to 16.8 kg/m(2) for women within the normal BMI ranges. BFMI values were 1.8 to 5.2 kg/m(2) for men and 3.9 to 8.2 kg/m(2) for women within the normal BMI ranges. BFMI values were 8.3 and 11.8 kg/m(2) in men and women, respectively, for obese BMI (>30 kg/m(2)). Normal ranges for %BF were 13.4 to 21.7 and 24.6 to 33.2 for men and women, respectively. CONCLUSION: BMI alone cannot provide information about the respective contribution of FFM or fat mass to body weight. This study presents FFMI and BFMI values that correspond to low, normal, overweight, and obese BMIs. FFMI and BFMI provide information about body compartments, regardless of height.     

Prospective study of optimal obesity index cutoffs for predicting development of multiple metabolic risk factors: the korean genome and epidemiology study

Background: In this prospective cohort study, we estimated the risk of developing more than 1 metabolic risk factor, using different obesity indices. In addition, we investigated the relative usefulness of the obesity indices for predicting development of such risk factors and calculated optimal cutoffs for the obesity indices.Methods: The cohort comprised 10 038 representative residents of a small city and a rural county who were recruited in 2001-2002. Follow-up examinations were conducted every 2 years. Among the 3857 participants without metabolic syndrome at baseline, 1102 new cases occurred during the 6-year follow-up. Receiver operating characteristic (ROC) curves for the obesity indices were plotted to compare the usefulness of the obesity indices.Results: The numbers of new cases of multiple metabolic risk factors among people in the highest quintiles of body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), and waist-height ratio at the baseline examination were 2 to 3 times those in the lowest quintiles. The area under the ROC curve for WHR was significantly higher than that for BMI. The optimal BMI cutoff was 24 kg/m(2) in men and women, and the optimal WC cutoffs were 80 cm and 78 cm in men and women, respectively.Conclusions: Both overall obesity and central obesity predicted risk of developing multiple metabolic risk factors, and WHR appeared to be a better discriminator than BMI. To prevent development of metabolic diseases among Koreans, it might be useful to lower the cutoff for abdominal obesity, as defined by WC.     

Waist circumference and obesity-associated risk factors among whites in the third National Health and Nutrition Examination Survey: clinical action thresholds

BACKGROUND: Waist circumference (WC) is strongly linked to obesity-associated risks. However, currently proposed WC risk thresholds are not based on associations with obesity-related risk factors but rather with body mass index (BMI; in kg/m(2)). OBJECTIVE: The objective was to determine the relations of WC to obesity-associated risk factors in a representative sample of US whites and to derive comparable risk thresholds for WC and BMI. DESIGN: Data on 9019 white participants of the third National Health and Nutrition Examination Survey were divided into 2 groups according to the presence of >or= 1 of 4 obesity-associated risk factors: low HDL cholesterol, high LDL cholesterol, high blood pressure, and high glucose. Odds ratio (OR) equations were derived from logistic regression models for WC and BMI with the use of the 25th percentile in the study population as the reference. Receiver operating characteristic curves for identifying risk factors were computed for WC and BMI. RESULTS: At BMIs of 25 and 30, ORs were 1.19 (95% CI: 1.06, 1.35) and 2.37 (95% CI: 1.33, 4.22) for men and 1.56 (95% CI: 1.29, 1.91) and 3.16 (95% CI: 1.94, 5.28) for women, respectively. The corresponding ORs for WC were at 90 and 100 cm for men and at 83 and 93 cm for women. Minima on the receiver operating characteristic curves for men were at 96 cm for WC and at 26 for BMI and for women were at 86 cm for WC and 25 for BMI. CONCLUSION: WC is more closely linked to cardiovascular disease risk factors than is BMI.     

Discrimination of health risk by combined body mass index and waist circumference

OBJECTIVE: NIH Clinical Guidelines (1998) recommend the measurement of waist circumference (WC, centimeters) within body mass index (BMI, kilograms per square meter) categories as a screening tool for increased health risk. RESEARCH METHODS AND PROCEDURES: The Canada Heart Health Surveys (1986 through 1992) were used to describe the prevalence of the metabolic syndrome in Canada and to test the use of the NIH guidelines for predicting metabolic risk factors. The sample included 7981 participants ages 20 to 74 years who had complete data for WC, BMI, high-density lipoprotein-cholesterol, triglycerides, diabetic status, and systolic and diastolic blood pressures. National Cholesterol Education Program Adult Treatment Panel III risk categories were used to identify the metabolic syndrome and associated risk factors. Logistic regression was used to test the hypothesis that WC improves the prediction of the metabolic syndrome, within overweight (25 to 29.9 kg/m(2)) and obese I (30 to 34.9 kg/m(2)) BMI categories. RESULTS: The prevalence of the metabolic syndrome was 17.0% in men and 13.2% in women. The odds ratios (OR) for the prediction of the metabolic syndrome were elevated in overweight [OR, 1.85; 95% confidence interval (95%CI), 1.02 to 3.35] and obese (OR, 2.35; 95%CI, 1.25 to 4.42) women with a high WC compared with overweight and obese women with a low WC, respectively. On the other hand, WC was not predictive of the metabolic syndrome or component risk factors in men, within BMI categories. DISCUSSION: In women already at increased health risk because of an elevated BMI, the additional measurement of WC may help identify cardiovascular risk.     

Body fat percentages measured by dual-energy X-ray absorptiometry corresponding to recently recommended body mass index cutoffs for overweight and obesity in children and adolescents aged 3-18 y

BACKGROUND: Body mass index (BMI; in kg/m2) cutoffs for use with children and adolescents aged 2-18 y that correspond to the well-accepted BMI cutoffs for overweight (> or = 25 but < 30) and obesity (> or = 30) in adults were published recently. OBJECTIVE: The objective was to estimate the percentage body fat (%BF) values typically associated with these BMI cutoffs in children and adolescents. DESIGN: The %BF was measured by dual-energy X-ray absorptiometry in 661 subjects (49% male) aged 3-18 y. Regression equations using BMI, age, and sex were developed to predict the %BF associated with BMI cutoffs for overweight (age-specific BMI equivalent to a BMI of 25 in an 18-y-old) and obesity (age-specific BMI equivalent to a BMI of 30 in an 18-y-old) over this age range. RESULTS: Measurements classified 17.1% of males and 19.8% of females as overweight and 5.5% of males and 7.5% of females as obese. The %BF associated with an obese BMI tended to be higher in peripubertal males (34-36%) than in younger (24-30%) or older (27-30%) males. Although the predicted %BF of young females was similar to that of young males, values rose steadily with age, such that an 18-y-old female with a BMI of 30 had an estimated %BF of 42%, whereas that in males of similar age was 27%. CONCLUSION: The %BF values associated with BMI classifications of overweight and obesity vary considerably with age in growing children, particularly in girls.     

Socioeconomic disparities in metabolic syndrome differ by gender: evidence from NHANES III

PURPOSE: The aim of the study is to examine whether socioeconomic position (SEP) is associated with metabolic syndrome and whether the association differs by gender and race/ethnicity. METHODS: Study participants were from the Third National Health and Nutrition Examination Survey. SEP was measured by using education and poverty income ratio (PIR). Metabolic syndrome was measured according to the National Institutes of Health guidelines. Multivariable-adjusted logistic regression analyses were performed. RESULTS: Low education (<12 years) was associated with metabolic syndrome in women (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.39-2.24) and less so in men (OR, 1.27; 95% CI, 0.97-1.66) versus more than 12 years of education. For income, low PIR (相似文献   

A proposed method for the evaluation of body fat in Japanese adults that predicts obesity

The present study was designed to develop a simple predictive equation for the percent body fat (%BF) in Japanese adults based on variables collected during health examinations. We hypothesized that a benchmark for defining metabolic syndrome and obesity could be based on %BF, which was measured by underwater weighing (UW) as a gold standard for body composition assessment. Thus, we developed a predictive equation for %BF derived from UW that may contribute to the assessment of obesity status, characterized by an excess accumulation of visceral or subcutaneous fat. The subjects were 810 Japanese participants (283 men, 527 women, ages 18-59 years). Anthropometric variables, including height, weight, 7 circumferences, and 8 skinfold thicknesses, were measured. The developed predictive equation was as follows: %BF = 10.558 × sex (1 for men; 2 for women) + 0.069 × age + 0.667 × body mass index + 0.314 × abdominal circumference − 35.881.The coefficient of determination (r²) was 0.69. The predicted %BF derived from this equation was highly correlated with UW-measured values and did not show underestimation or overestimation in either sex. These data suggested that this predictive equation for %BF can be used for all Japanese adults and does not require the use of medical equipment and special measurement techniques. By combining the equation for %BF developed in this study with a %BF cutoff value of metabolic syndrome and obesity (>25.0% in men and >30.0% in women), all Japanese adults can easily and conveniently assess obesity status.     

Measures of adiposity in the identification of metabolic abnormalities in elderly men

BACKGROUND: Body mass index (BMI; in kg/m(2)) is considered a poor indicator of overall and abdominal obesity in the elderly. OBJECTIVES: Our goal was to determine which simple anthropometric measurements [BMI, waist-to-hip ratio (WHR), waist circumference (WC), percentage body fat (%BF), or fat mass (FM)] are most closely associated with metabolic risk factors and insulin resistance in elderly men. DESIGN: This was a cross-sectional study of 2924 men aged 60-79 y with no history of coronary heart disease, stroke, or diabetes who were drawn from general practices in 24 British towns. RESULTS: BMI and WC were the measures most strongly associated with the metabolic syndrome (>/=3 of the following: hypertension, low HDL cholesterol, high triacylglycerols, or high blood glucose) and insulin resistance. For a 1-SD increase in BMI, WC, WHR, %BF, and FM, the odds ratios (95% CIs) of having the metabolic syndrome after adjustment for age, socioeconomic status, smoking status, and physical activity were as follows: BMI, 1.61 (1.44, 1.79); WC, 1.65 (1.48, 1.81); WHR, 1.49 (1.34, 1.66); %BF, 1.41 (1.25, 1.59); and FM, 1.53 (1.38, 1.70). For insulin resistance, the odds ratios (95% CIs) were as follows: 2.48 (2.22, 2.77), 2.46 (2.19, 2.65), 1.75 (1.59, 1.93), 1.79 (1.60, 2.00), and 2.10 (1.88, 2.34), respectively. In normal-weight (BMI < 25) and overweight (BMI 25-29.9) men, the presence of the metabolic syndrome and insulin resistance increased with increasing WC; this did not occur in obese men. CONCLUSIONS: BMI and WC are the simple measures of adiposity most strongly associated with metabolic abnormalities in elderly men. Our findings suggest that WC can be used as a complementary measurement to identify health risks in normal-weight and overweight elderly persons.     

Defining obesity by body mass index in the Thai population: an epidemiologic study

The objective of this study was to develop cut-off values and evaluate the accuracy of body mass index (BMI) in the definition of obesity in the Thai population. A cross-sectional, epidemiologic study in 340 men and 507 women aged 50 +/- 16 yr (mean +/- SD; range: 20-84 yr), were sampled by stratified clustering sampling method. Body composition, including percentage body fat (%BF), was measured by dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). BMI was obtained by dividing weight (in kg) by height (in m2). The "golden standard "for defining obesity was %BF > or =25% in men and %BF > or =35% in women. The %BF-based prevalence of obesity in men and women was 18.8% and 39.5%, respectively. However, using the BMI cut-off of > or =30, only 2.9% of men and 8.9% of women were classified as obese. In the cubic regression model, BMI was a significant predictor of %BF, such that in men a BMI of 27 kg/m2 would predict a %BF of 25%, and in women a BMI of 25 kg/m2 would correspond to a %BF of 35%. The area under the receiver operating characteristic curve for BMI was approximately 0.87 (95% CI: 0.82-0.92) and 0.86 (95% CI: 0.83-0.90) in men and women, respectively. In conclusion, for the Thai population, BMI is a reasonably useful indicator of obesity; however, the cut-off values of BMI for diagnosing obesity should be lowered to 27 kg/m2 in men and 25 kg/m2 in women.     

Anthropometric cutoff points for predicting chronic diseases in the Mexican National Health Survey 2000

OBJECTIVE: To determine optimum anthropometric cutoffs for predicting the likelihood ratios of type 2 diabetes mellitus (DM) and hypertension (HT) in Mexicans. RESEARCH METHODS AND PROCEDURES: Data from a randomly selected, nationally representative health survey (2000) with 11,730 men [37.4 (+/- 12.9) years] and 26,647 women [37.3(+/- 12.9) years] were assessed for values of body mass index (BMI) and waist circumference (WC) for predicting DM or HT by receiver operating characteristic curve analyses. Likelihood ratios for DM and HT were calculated, and BMIs or WCs for public-health screening were developed. Subanalyses included regional data. RESULTS: Likelihood ratios of DM and HT increased from BMI values of 22 to 24 kg/m(2) in both sexes and with WC values of 75 to 80 cm in men and 70 to 80 cm in women. The best BMI cutoffs for predicting DM were 26.3 to 27.4 kg/m(2) in men and 27.7 to 28.9 kg/m(2) in women, with similar values for HT, i.e., 26.2 to 27.0 kg/m(2) and 27.7 to 28.5 kg/m(2), for men and women, respectively; WC cutoffs for DM were 93 to 98 cm in men and 94 to 99 cm in women, and cutoffs for HT were 92 to 96 cm and 93 to 96 cm for men and women, respectively. The WC cutoffs had higher sensitivity and specificity than those of BMI. DISCUSSION: The risk for DM and HT starts at lower levels of BMI and WC than those suggested by WHO. WC is a better discriminator than BMI measures for use in public health.     

Ability of new octapolar bioimpedance spectroscopy analyzers to predict 4-component-model percentage body fat in Hispanic, black, and white adults

BACKGROUND: New, vertical, 8-electrode bioimpedance spectroscopy (BIS) analyzers provide detailed body-composition and nutritional information within 2 min. This is the first report on BIS's accuracy in predicting relative fatness [percentage body fat (%BF)] in a heterogeneous sample according to a multicomponent model criterion. OBJECTIVE: We compared %BF measurements from 2 BIS devices with those from a multicomponent model in a sample of Hispanic, black, and white adults. DESIGN: Equal numbers of apparently healthy men and women (n = 75 of each) from each racial-ethnic group, diverse in body mass index and age, volunteered. Reference %BF (%BF(4C)) was computed by using a 4-component (4C) model with total bone mineral content obtained from dual-energy X-ray absorptiometry, body density from underwater weighing with measured residual lung volume, and total body water from traditional BIS. Estimations from InBody 720 (%BF(720)) and InBody 320 (%BF(320)) BIS analyzers were validated against %BF(4C). RESULTS: The %BF(720) (r = 0.85, SEE = 5.19%BF) and %BF(320) (r = 0.84, SEE = 5.17%BF) correlations were significant (P < 0.05) in the men; main effects were nonsignificant. Correlations for %BF(720) (r = 0.88, SEE = 4.85%BF) and %BF(320) (r = 0.89, SEE = 4.82%BF) also were significant in the women (P < 0.05); there was a main effect for method but not race-ethnicity. There were no sex-specific overestimations or underestimations at the extremes of the distributions. CONCLUSIONS: BIS estimates of %BF(4C) were well correlated in men and women. There were no significant methodologic differences in the men. The %BF(4C) was significantly underestimated by %BF(720) and %BF(320) in the women.     

Prediction of percentage body fat in rural thai population using simple anthropometric measurements

OBJECTIVE: To develop and validate sex-specific equations for predicting percentage body fat (%BF) in rural Thai population, based on BMI and anthropometric measurements. RESEARCH METHODS AND PROCEDURES: %BF (DXA; GE Lunar Corp., Madison, WI) was measured in 181 men and 255 women who were healthy and between 20 and 84 years old. Anthropometric measures such as weight (kilograms), height (centimeters), BMI (kilograms per meter squared), waist circumference (centimeters), hip circumference (centimeters), thickness at triceps skinfold (millimeters), biceps skinfold (millimeters), subscapular skinfold (millimeters), and suprailiac skinfold (millimeters) were also measured. The sample was randomly divided into a development group (98 men and 125 women) and a validation group (83 men and 130 women). Regression equations of %BF derived from the development group were then evaluated for accuracy in the validation group. RESULTS: The equation for estimating %BF in men was: %BF(men) = 0.42 x subscapular skinfold + 0.62 x BMI - 0.28 x biceps skinfold + 0.17 x waist circumference - 18.47, and in women: %BF(women) = 0.42 x hip circumference + 0.17 x suprailiac skinfold + 0.46 x BMI - 23.75. The coefficient of determination (R2) for both equations was 0.68. Without anthropometric variables, the predictive equation using BMI, age, and sex was: %BF = 1.65 x BMI + 0.06 x age - 15.3 x sex - 10.67 (where sex = 1 for men and sex = 0 for women), with R2 = 0.83. When these equations were applied to the validation sample, the difference between measured and predicted %BF ranged between +/-9%, and the positive predictive values were above 0.9. DISCUSSION: These results suggest that simple, noninvasive, and inexpensive anthropometric variables may provide an accurate estimate of %BF and could potentially aid the diagnosis of obesity in rural Thais.     

Appropriate body mass index and waist circumference cutoffs for categorization of overweight and central adiposity among Chinese adults

BACKGROUND: Recent data suggest that current overweight and central adiposity guidelines based on Western populations are not appropriate for Asian populations. The published data among Chinese are insufficient to address this issue. OBJECTIVE: We aimed to identify cutoffs for body mass index (BMI; in kg/m(2)) and waist circumference that confer increased risk of cardiovascular disease in Chinese adults as would be consistent with overweight and central adiposity. DESIGN: A nationally representative, cross-sectional sample of 15 239 Chinese adults aged 35-74 y was studied. RESULTS: Mean blood pressure, total cholesterol, LDL-cholesterol, triacylglycerol, and glucose values were incrementally higher and mean HDL-cholesterol values were incrementally lower with each unit increase in BMI and waist circumference in both men and women. Both the point at which sensitivity equaled specificity and the shortest distance in the receiver operating characteristic curves for hypertension, dyslipidemia, diabetes, or >/=2 of these risk factors suggested a BMI cutoff of 24 and a waist circumference cutoff of 80 cm for both men and women. CONCLUSIONS: Lower cutoffs for BMI and waist circumference are needed in the identification of Chinese patients at high risk of cardiovascular disease.     

成人代谢综合征适宜体质指数切点的研究

目的:探讨成人诊断代谢综合征的适宜体质指数切点。方法:以2008-2009年南京地区参加健康体检成人27822人为研究对象,测量身高、体重、血压,采集空腹静脉血测定葡萄糖、血甘油三酯、高密度脂蛋白胆固醇,通过对体质指数和各代谢异常危险因素的分析,建立受试者工作特征曲线(ROC曲线),探讨适宜的体质指数诊断切点。结果:男性出现代谢异常危险因素的比例高于女性;根据ROC曲线分析,在男性BMI为24.32、女性BMI为23.06时,预测≥2项代谢异常危险因素的Youden指数最大。结论:南京地区成人代谢综合征的体质指数切点,以男性BMI=24,女性BMI=23比较合适。     

The effect of decision rules on the choice of a body mass index cutoff for obesity: examples from African American and white women

BACKGROUND: Ethnic differences in the relation of body mass index (BMI; in kg/m2) to morbidity and mortality have led investigators to question whether a single cutoff for obesity should be applied to all ethnic groups. OBJECTIVE: The effects of using 4 different outcomes and 3 different measures of effect as criteria for comparing BMI cutoffs were shown with the use of data from 45- to 64-y-old African American and white women. DESIGN: Data were from the Cancer Prevention Study I (CPS-I) and the Atherosclerosis Risk in Communities (ARIC) Study. The outcomes were mortality (9211 deaths), diabetes (757 cases), hypertension (1518 cases), and hypertriglyceridemia (1264 cases). The measures of effect were incidence rate, rate ratio, and rate difference. The BMI in African American women that was associated with a risk equivalent to that of white women with a BMI of 30 was estimated. RESULTS: There was no significant association between BMI and mortality in African American women. The BMI in African American women that was associated with a risk of diabetes equivalent to that of white women with a BMI of 30 was 28.0-34.5, depending on the measure of effect. For hypertension, the equivalent risk in African American women occurred at a BMI of <18-38, depending on the measure of effect. There was no BMI at which African American women had an incidence rate or rate ratio for hypertriglyceridemia that was as high as that of white women with a BMI of 30. CONCLUSION: BMI cutoffs associated with equivalent risk across ethnic groups differ widely depending on the outcome and the risk estimate.     

Accuracy of anthropometric measurements in estimating fat mass in individuals with 21-hydroxylase deficiency

ObjectiveThe use of anthropometric measurements to estimate the percentage of body fat (%BF) is easy and inexpensive. However, the accuracy of these methods in patients with 21-hydroxylase deficiency (21OHD) has not been explored. The objective of this study was to evaluate the accuracy of skinfold-based models, body mass index (BMI), and waist circumference (WC) in estimations of %BF using dual-energy X-ray absorptiometry (DXA) as the reference method in individuals with 21OHD.MethodsFifty-four 21OHD patients (32 women and 22 men), aged 7 to 20 y, were recruited for the study. DXA was used to determine %BF; four predictive skinfold equations, BMI, and WC were assessed for accuracy in determining %BF.ResultsAll predictive skinfold equations were highly associated (R, range: 0.82-0.89) with DXA %BF values. In women, BMI and WC showed moderate correlations (R = 0.69 for both BMI and WC) with DXA values. In contrast, among men there was a low explanatory power for BMI (13%) and WC (4%) and high errors (BMI, 6.9%; WC, 7.4%). All predictive equations significantly underestimated %BF (range of differences, ?4.1 to ?8.9) compared with DXA (women, 31.3 ± 6.1; men, 24.4 ± 7.3), and large limits of agreement were observed (range, ?15.3 to 1.7 and ?15.5 to 4.2 for women and men, respectively).ConclusionIn children and adolescents with 21OHD, %BF as estimated by skinfold measurements was associated more strongly with DXA-assessed %BF than both BMI and WC. However, still, the skinfold-based assessment underestimated DXA %BF and showed moderate agreement.     

Serum ferritin and risk of the metabolic syndrome in some Korean rural residents]

OBJECTIVES: The purpose of this study was to examine the relationship between serum ferritin and the metabolic syndrome (MS). METHODS: We conducted a cross-sectional study of 1,444 adults over age 40 and under age 70 that lived in a rural area and participated in a survey conducted as part of the Korean Rural Genomic Cohort Study (KRGCS). The MS was defined as the presence of at least three of the followings: elevated blood pressure, low high density lipoprotein cholesterol, elevated serum triglycerides, elevated plasma glucose, or abdominal obesity. After adjustment for age, alcohol intake, menopausal status, body mass index (BMI), high sensitivity C-reactive protein (hs-CRP), and alanine aminotransferase (ALT), odds ratios (ORs) for the prevalence of the MS by sex were calculated for quartiles of serum ferritin using logistic regression analysis. RESULTS: The MS was more common in those persons with the highest levels of serum ferritin, compared to persons with the lowest levels, in men (37.1% vs. 22.4%, p=0.006) and women (58.8% vs. 34.8, p<0.001). In both sexes, the greater the number of MS components presents, the greater the serum ferritin levels. After adjustment for age, alcohol intake, and menopausal status, the OR for metabolic syndrome, comparing the fourth quartile of ferritin with the first quartile, was 2.21 (95% confidence interval; CI=1.26-3.87; p-trend=0.024) in men and 2.10 (95% CI=1.40-3.17; p-trend=0.001) in women. However, after further adjustment for BMI, hs-CRP, and ALT, the ORs were statistically attenuated in both sexes. CONCLUSIONS: Moderately elevated serum ferritin levels were not independently associated with the prevalence of the MS after adjusting for other risk factors. Further studies are needed to obtain evidence concerning the association between serum ferritin levels and the MS.