Optimal cutoff point of waist circumference and use of home blood pressure as a definition of metabolic syndrome: the Ohasama study

Estimation of visceral fat area using criteria for metabolic syndrome: A cross-sectional study

BACKGROUND AND AIMS

The aim of this study was to calculate the visceral fat area (VFA) based on the criteria for metabolic syndrome (MetS).

METHODS

A multiple regression analysis was performed to determine the estimated VFA using data from Japanese participants (2315 men and 1684 women). Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal estimated VFA cutoff for the diagnosis of central obesity. The cutoff was also applied to a second cohort to validate the model.

RESULTS

The estimated VFA was calculated using the MetS criteria, age, and body mass index (adjusted coefficient of determination = 0.682 for men and 0.726 for women). The area under the ROC curve for waist circumference, VFA, and estimated VFA were 0.669, 0.741, and 0.749, respectively, for men and 0.711, 0.787, and 0.803, respectively, for women. The optimal cutoffs for estimated VFA were 128.1 cm² for men and 82.2 cm² for women. Multivariate logistic regression for heart disease revealed that estimated VFA, rather than waist circumference, was associated with a high risk of heart disease.

CONCLUSION

The estimated VFA is a better index of central obesity than waist circumference and VFA for the diagnosis of MetS.

Using Latent Class Analysis to Identify Different Risk Patterns for Patients With Masked Hypertension

Background: There is controversy whether masked hypertension (MHT) requires additional intervention. The aim of this study is to evaluate whether MHT accompanied with high-risk metabolic syndrome (MetS), as the subphenotype, will have a different prognosis from low-risk MetS.

Methods: We applied latent class analysis to identify subphenotypes of MHT, using the clinical and biological information collected from High-risk Cardiovascular Factor Screening and Chronic Disease Management Programme. We modeled the data, examined the relationship between subphenotypes and clinical outcomes, and further explored the impact of antihypertensive medication.

Results: We included a total of 140 patients with MHT for analysis. The latent class model showed that the two-class (high/low-risk MetS) model was most suitable for MHT classification. The high-risk MetS subphenotype was characterized by larger waist circumference, lower HDL-C, higher fasting blood glucose and triglycerides, and prevalence of diabetes. After four years of follow-up, participants in subphenotype 1 had a higher non-major adverse cardiovascular event (MACE) survival probability than those in subphenotype 2 (P = 0.016). There was no interaction between different subphenotypes and the use of antihypertensive medications affecting the occurrence of MACE.

Conclusions: We have identified two subphenotypes in MHT that have different metabolic characteristics and prognosis, which could give a clue to the importance of tracing the clinical correlation between MHT and metabolic risk factors. For patients with MHT and high-risk MetS, antihypertensive therapy may be insufficient.

Aging attenuates the association of central obesity with the accumulation of metabolic risk factors when assessed using the waist circumference measured at the umbilical level (the Japanese standard method)

Objective:

The objective of this study was to clarify the generation and gender differences in the association between central obesity and the accumulation of metabolic risk factors (RFs) in the Japanese population.

Material and methods:

A total of 12 389 subjects (age: 18–80 years) without receiving medication for diabetes, dyslipidemia or hypertension were enrolled in this study and divided according to age and gender. In each group, we performed analyses as follows: (1) a receiver operating characteristic (ROC) analysis to evaluate the utility of the waist circumference (WC) for detecting subjects with multiple RFs of metabolic syndrome (MS); (2) a cross-sectional study to examine the relationship between the WC and the odds ratio (OR) for detecting those subjects and (3) a longitudinal study to examine how longitudinal changes (Δ) in WC over a 1-year period affected the values of each metabolic RF.

Results:

With age, the WC cutoff values yielding the maximum Youden index for detecting subjects with multiple RFs increased only in women, and the areas under the curves of the ROC analysis of WC for detecting those subjects decreased in both genders. The positive correlation between the WC and the OR for detecting subjects with multiple RFs became weaker with age, especially in women. In the longitudinal study, the significant correlation between ΔWC and Δ each metabolic RF, except for hypertension, and between ΔWC and Δ the number of RFs became weaker with age in women, whereas the significant correlation between ΔWC and Δ the number of RFs was not affected with age in men. In women aged ⩾60 years, none of the changes in each metabolic RF were significantly associated with ΔWC.

Conclusions:

Aging attenuates the association of central obesity with the accumulation of metabolic RFs, especially in women.

Body mass index is more strongly associated with hypertension than waist circumference in apparently healthy Japanese men and women

Obesity is associated with hypertension. However, it is controversial which obesity index, body mass index (BMI) or waist circumference (WC), is more strongly associated with hypertension. We compared the cross-sectional associations of BMI and WC with hypertension. Logistic regressions using hypertension as a dependent variable and age, BMI, WC, fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, smoking status, drinking status, and physical activity as independent variables were performed using data from apparently healthy 1,803 Japanese men aged 49.9 ± 9.0 and 1,150 women aged 49.5 ± 9.0 excluding subjects with a history of cardiovascular disease, or with antidiabetic, antihypertensive and/or antihyperlipidemic medications. The odds ratio [95% confidence interval] of 1 kg/m² increase in BMI and that of 1 cm increase in WC for diagnosing hypertension were 1.23 [1.11-1.36] (p < 0.0001) and 0.99 [0.95-1.02] (p = 0.4) in men and 1.35 [1.16-1.58] (p < 0.0001) and 0.97 [0.91-1.03] (p = 0.4) in women, respectively. Thus, BMI, but not WC, was independently associated with hypertension in apparently healthy Japanese men and women.

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

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

Optimal cut-off point of waist circumference for the diagnosis of metabolic syndrome in Japanese subjects

Metabolic syndrome (MetS) has been redefined by a new criterion in Japan, in which waist circumference cut-off points, that is 85 cm for men and 90 cm for women, are used; however, objections are rising against this criterion. The present study examined the criterion for waist circumference to predict the accumulation of the components of MetS. In the present study, we used data for 5972 Japanese people who received annual health examinations, and 621 men (16.3%) and 51 women (2.4%) were diagnosed as having MetS. A cut-off point as a predictor for two or more components of MetS was evaluated by the sensitivity/specificity and a receiver operating characteristic analysis. The optimal point of waist circumference was estimated as being approximately 84 cm for men and 80 cm for women. We therefore recommend revising the cut-off value for the criterion of MetS in women according to our results and studies from other investigators. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00020.x, 2010).

Abdominal circumference should not be a required criterion for the diagnosis of metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is an established concept. However, it is characterized by a number of different definitions as well as different cut-off points (COPs) for waist circumference (WC) and different modes for incorporating WC into the diagnostic criteria.

METHODS

Abdominal ultrasonography was performed in 2,333 subjects who also underwent comprehensive medical examinations between April and July 2006. The odds ratios for the number of MetS components were calculated by taking central obesity status into account and considering concurrent fatty liver as an independent variable. We compared the areas under the receiver operating characteristic (ROC) curves for fatty liver and MetS using several MetS criteria.

RESULTS

Regardless of the WC criterion selected, we observed a strong linear trend for an association (trend P < 0.0001) between MetS and the number of components. The odds ratio (OR) of subjects without central obesity but with all three MetS components was 9.69 (95% confidence interval 3.11-30.2) in men and 55.3 (6.34-483) in women. The COP for the largest area under the curve in men and women was ≥82 cm (OR 0.701) and ≥77 cm (OR 0.699), respectively, when WC was considered as a component. When WC distribution is taken into consideration, practical and appropriate COPs should be ≥85 cm for men and ≥80 cm for women.

CONCLUSION

We suggest that a WC of ≥85 cm for men and ≥80 cm for women would be optimal COPs for the central obesity criteria in the Japanese population. In addition, central obesity should be incorporated as a component of MetS rather than an essential requirement for the diagnosis of MetS.

Comparison among body mass index (BMI), waist circumference (WC), and percent body fat (%BF) as anthropometric markers for the clustering of metabolic risk factors in Japanese

OBJECTIVE

To compare body mass index (BMI), waist circumference (WC), and percent body fat (%BF) as markers for the clustering of metabolic risk factors in Japanese.

METHODS

Age-adjusted correlation coefficients (Rs) were calculated between the three anthropometric markers of obesity and metabolic risk factors in 2,444 men and 1,442 women among Japanese. Areas under receiver operating characteristic curves (AUCs) of BMI, WC, and %BF were calculated for diagnosing the clustering of 1 or more, 2 or more, 3 or more, and 4 risk factors among increased blood pressure, impaired fasting glucose, increased triglycerides, and decreased HDL cholesterol and for the clustering of 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, and 6 risk factors among the upper four risk factors as well as increased high-sensitivity C-reactive protein and increased LDL cholesterol.

RESULTS

The Rs were not significantly different among BMI, WC, and %BF except for the difference between the R of BMI (0.217) and that of %BF (0.283) with LDL cholesterol in men (p=0.014). The AUCs of BMI, WC, and %BF for diagnosing any of the risk factor clustering patterns defined above were not significantly different in both men and women.

CONCLUSION

The AUCs for diagnosing the clustering of metabolic risk factors were not significantly different among BMI, WC, and %BF.

Optimal cutoff points of waist circumference for the criteria of abdominal obesity: comparison with the criteria of the International Diabetes Federation

BACKGROUND

There are few studies that compare measures of diagnostic accuracy for selected waist cutoff points and the criteria of abdominal obesity given by the International Diabetes Federation (IDF) and the National Cholesterol Education Program (NCEP).

METHODS AND RESULTS

The present study utilized data from the Third Korean National Health and Nutrition Examination Survey. Analyses for receiver-operating characteristic (ROC) curve were performed with data for 4,677 men and women aged 20-80 years who reported being free of a physician-diagnosed cardiovascular disease or cancer. On the basis of measures of diagnostic accuracy, including minimum distance to ROC curve and Youden index, waist circumference of 84-86 cm for men and of 78-80 cm for women were found to be optimal cutoff points. The study also demonstrated that the use of smaller waist circumference for diagnosis of the metabolic syndrome decreases discrepancies between the prevalence of the IDF-defined metabolic syndrome and that of the NCEP-defined metabolic syndrome.

CONCLUSIONS

Waist circumference of 90 cm, the cutoff point given by the IDF for Asian men, may not be an appropriate value for Korean men, while its cutoff point for Asian women is appropriate for Korean women.

Characteristics of reference intervals of metabolic factors in healthy Japanese: a proposal to set generation- and gender-specific diagnostic criteria for metabolic syndrome

AIM

To verify the clinical diagnostic criteria for metabolic syndrome (MetS-Criteria) for Japanese (Japanese-Criteria) from the viewpoint of reference intervals (RIs) of metabolic factors.

METHODS

In healthy subjects selected from 1,379 males and 1,528 females aged 20-65 years, generation-and gender-specific RIs of metabolic factors were determined. Then, from the upper or lower limits of the RIs, new MetS-Criteria were tentatively set (New-Criteria).

RESULTS

RIs of some metabolic factors were associated with gender- and/or generation-specific differences. In both genders, the New-Criteria for subjects in their 40s and over (older adults) were comparable to the Japanese-Criteria, whereas the New-Criteria for these in their 30s and less (younger adults) were not. Levels of cut-off values in the New-Criteria for younger adults were mostly between those of the Japanese-Criteria and recently established MetS-Criteria for adolescents. The prevalence of metabolic syndrome estimated by the Japanese-Criteria and the New-Criteria well corresponded in older adults but significantly differed in younger adults.

CONCLUSION

MetS-Criteria prepared on gender- and generation-specific bases may be necessary. The Japanese-Criteria, which may still have room for minor changes, seem to be valid at least for older adults; however, new MetS-Criteria should be established for younger adults.