Visceral adipose tissue as a predictor for metabolic risk factors in the Korean population

Subcutaneous and Visceral Adipose Tissue Reference Values From the Framingham Heart Study Thoracic and Abdominal CT

BACKGROUND

Computed tomography (CT) captures the quantity, density, and distribution of subcutaneous and visceral (SAT and VAT) adipose tissue compartments. These metrics may change with age and sex.

OBJECTIVE

The study aims to provide age-, sex-, and vertebral level-specific reference values for SAT on chest CT and for SAT and VAT on abdomen CT.

MATERIALS AND METHODS

This secondary analysis of an observational study describes SAT and VAT measurements in participants of the Framingham Heart Study without known cancer diagnosis who underwent at least 1 of 2 CT examinations between 2002 and 2011. We used a previously validated machine learning-assisted pipeline and rigorous quality assurance to segment SAT at the fifth, eighth, and tenth thoracic vertebra (T5, T8, T10) and SAT and VAT at the third lumbar vertebra (L3). For each metric, we measured cross-sectional area (cm2) and mean attenuation (Hounsfield units [HU]) and calculated index (area/height2) (cm2/m2) and gauge (attenuation × index) (HU × cm2/m2). We summarized body composition metrics by age and sex and modeled sex-, age-, and vertebral level-specific reference curves.

RESULTS

We included 14,898 single-level measurements from up to 4 vertebral levels of 3797 scans of 3730 Framingham Heart Study participants (1889 [51%] male with a mean [standard deviation] age of 55.6 ± 10.6 years; range, 38-81 years). The mean VAT index increased with age from 65 (cm2/m2) in males and 29 (cm2/m2) in females in the <45-year-old age group to 99 (cm2/m2) in males and 60 (cm2/m2) in females in >75-year-old age group. The increase of SAT with age was less pronounced, resulting in the VAT/SAT ratio increasing with age. A free R package and online interactive visual web interface allow access to reference values.

CONCLUSIONS

This study establishes age-, sex-, and vertebral level-specific reference values for CT-assessed SAT at vertebral levels T5, T8, T10, and L3 and VAT at vertebral level L3.

Sex Differences of Visceral Fat Area and Visceral-to-Subcutaneous Fat Ratio for the Risk of Incident Type 2 Diabetes Mellitus

BACKGROUND

This study aimed to determine the optimal cut-off values of visceral fat area (VFA) and visceral-to-subcutaneous fat ratio (VSR) for predicting incident type 2 diabetes mellitus (T2DM).

METHODS

A total of 10,882 individuals (6,835 men; 4,047 women) free of T2DM at baseline aged between 30 and 79 years who underwent abdominal computed tomography scan between 2012 and 2013 as a part of routine health check-ups were included and followed. VFA, subcutaneous fat area, and VSR on L3 vertebral level were measured at baseline.

RESULTS

During a median follow-up of 4.8 years, 730 (8.1% for men; 4.3% for women) incident cases of T2DM were identified. Receiver operating characteristic curve analysis showed that the optimal cut-off values of VFA and VSR for predicting incident T2DM were 130.03 cm2 and 1.08 in men, respectively, and 85.7 cm2 and 0.48 in women, respectively. Regardless of sex, higher VFA and VSR were significantly associated with a higher risk of incident T2DM. Compared with the lowest quartiles of VFA and VSR, the highest quartiles had adjusted odds ratios of 2.62 (95% confidence interval [CI], 1.73 to 3.97) and 1.55 (95% CI, 1.14 to 2.11) in men, respectively, and 32.49 (95% CI, 7.42 to 142.02) and 11.07 (95% CI, 3.89 to 31.50) in women, respectively.

CONCLUSION

Higher VFA and VSR at baseline were independent risk factors for the development of T2DM. Sex-specific reference values for visceral fat obesity (VFA ≥130 cm2 or VSR ≥1.0 in men; VFA ≥85 cm2 or VSR ≥0.5 in women) are proposed for the prediction of incident T2DM.

Risk factors for hemorrhoidal disease among healthy young and middle-aged Korean adults

Hemorrhoidal disease is a highly prevalent anorectal condition causing substantial discomfort, disability, and decreased quality of life. Evidence on preventable risk factors for hemorrhoidal disease is limited. We conducted a cross-sectional study of 194,620 healthy men and women who completed a health screening exam including colonoscopy in 2011–2017. We evaluated potential risk factors of hemorrhoidal disease, including lifestyle factors, medical history, birth history, gastrointestinal symptoms, and anthropometric measurements. The prevalence of hemorrhoidal disease was 16.6%, and it was higher in females than in males (17.2 vs. 16.3%; P < 0.001). Compared to men, the prevalence of hemorrhoidal disease was higher in parous women (adjusted odds ratio [OR] 1.06; 95% confidence interval [CI] 1.02–1.10), and lower in nulliparous women (adjusted OR 0.92; 95% CI 0.86–0.98). In the adjusted analyses, older age, female sex, smoking, overweight, and being hypertensive were independently associated with the presence of hemorrhoidal disease. The prevalence of hemorrhoidal disease was positively associated with body mass index and waist circumference in parous women. The prevalence of hemorrhoidal disease was higher in older age, females, ever-smokers, and hypertensive participants. The association of excess adiposity with the prevalence of hemorrhoidal disease differed by sex and parity.

[Effect of a Physical Activity Promoting Program Based on the IMB Model on Obese-Metabolic Health Outcomes among Obese Older Adults with Knee Osteoarthritis]

PURPOSE

This study examined the effects of a physical activity promoting program based on the Information-Motivation-Behavioral Skills (IMB) model on physical activity and health outcomes among obese older adults with knee osteoarthritis.

METHODS

This study utilized a randomized controlled trial with a convenience sample of 75 obese older adults with knee osteoarthritis in a university hospital. The older adults in the intervention group participated in a 12-week program involving weekly group sessions and monitoring calls with education booklets and video clips for exercise dances, while those in the control group received an usual care. Outcomes were measured using self-report questionnaires, anthropometrics, and blood analyses. The intervention effects were analyzed using Mann-Whitney U test and ANCOVA.

RESULTS

The mean age of participants was 74.9 years with 84.0% women. The intervention group at 12 weeks showed significantly greater improvements in self-efficacy for physical activity (F=81.92, p<.001), physical activity amounts (Z=-2.21, p=.044), knee joint function (F=15.88, p<.001), and health-related quality of life (F=14.89, p<.001) compared to the control group. Among obese-metabolic outcomes, the intervention group at 12 weeks showed a significant decrease in visceral fat mass (F=7.57, p=.008) and improvement in high-density level cholesterol (F=9.51, p=.003) compared to the control group.

CONCLUSION

Study findings support the need for an IMB based physical activity program for promoting physical activity, knee function and health outcomes in obese older adults with knee osteoarthritis. Longitudinal studies are warranted to confirm the persistence of obese-metabolic effects in clinical settings.

Impact of Visceral Obesity on the Risk of Incident Metabolic Syndrome in Metabolically Healthy Normal Weight and Overweight Groups: A Longitudinal Cohort Study in Korea

Background

Although both obesity, measured by body mass index, and visceral obesity are known to be major risk factors of metabolic syndrome and its components, there have been debates on the relative contribution of general obesity and visceral obesity to the development of metabolic syndrome.

Methods

We performed a large longitudinal cohort study of 3,093 subjects (age range, 18–65 years) who were metabolically healthy and had a normal weight who received health screenings over a 3-year follow-up period. Cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for incident metabolic syndrome and its components per sex-specific 1-standard deviation (SD) increase in visceral adipose tissue (VAT) and body mass index.

Results

Both obesity and visceral obesity increased the risk of incident metabolic syndrome, but when HR was compared per sex-specific 1-SD, visceral obesity appeared to confer more risk than simple obesity. The HR for 1-SD of body mass index was 1.19 (95% CI, 1.07–1.32; P=0.001) in men and 1.29 (95% CI, 1.10–1.52; P=0.002) in women, while the HR for 1-SD of VAT was 1.29 (95% CI, 1.15–1.44; P<0.001) in men and 1.50 (95% CI, 1.28–1.75; P<0.001) in women.

Conclusion

Visceral obesity and obesity were longitudinally associated with an increased risk of incident metabolic syndrome among metabolically healthy adults, and visceral fat accumulation appears to be better predictor of metabolic syndrome.

Optimal cut-points of visceral adipose tissue areas for cardiometabolic risk factors in a Chinese population: a cross-sectional study

AIM

To determine the optimal cut-points of visceral adipose tissue (VAT) areas at different anatomic levels to discriminate participants with cardiometabolic risk factors in a Chinese middle-aged population.

METHODS

A total of 1744 individuals who underwent regular health checks in Nanjing BENQ Medical Center from January 2013 to December 2016 were included in this cross-sectional study. VAT areas were measured by abdominal quantitative computed tomography at the L2/3 intervertebral disk and umbilicus levels. Cardiometabolic risk factors including serum triglycerides, HDL cholesterol levels, plasma glucose and blood pressure were defined using IDF 2005 criteria for metabolic syndrome.

RESULTS

The cut-points for VAT area at the umbilicus level were 111 cm² for men and 96 cm² for women to identify people with one or more cardiometabolic risk factors. For VAT area at the L2/3 level, the optimal cut-points were 142 cm² for men and 115 cm² for women. A VAT area at the L2/3 level of ≥ 142 cm² for men or 115 cm² for women significantly increased the prevalence of hyperglycaemia [odds ratio (OR) 3.18, 95% confidence interval (CI) 2.45-4.13], hypertension (OR 2.81, 95% CI 2.27-3.49) and dyslipidaemia (OR 4.37, 95% CI 3.50-5.45) after adjusting age.

CONCLUSIONS

The optimal cut-points for VAT area at the umbilicus level and L2/3 level were 111 cm² and 142 cm² for men and 96 cm² and 115 cm² for women to identify participants with one or more cardiometabolic risk factors.

Perspective on Diagnostic Criteria for Obesity and Abdominal Obesity in Korean Adults

Excessive body weight is associated with increased health risks in humans. In general, the risk of mortality increases with greater obesity. The 2018 guideline for the management of obesity by the Korean Society for the Study of Obesity proposed the body mass index (BMI) cut-off levels of 25 kg/m2 and 23 kg/m2 as diagnostic criteria for obesity and overweight (pre-obese) in Korean adults, respectively. Abdominal obesity has been defined as waist circumference (WC) ≥90 cm in men and WC ≥85 cm in women. In this review, the validity of these criteria for Korean adults was examined based on the evidence regarding the associations of obesity index with mortality and morbidity. The American Association of Clinical Endocrinologists/American College of Endocrinology algorithm and American Diabetes Association guideline for the medical care of obese and overweight patients support a BMI of 25 kg/m2 and 23 kg/m2, respectively, as the cut-off levels for Asians (and some ethnicities) corresponding to the BMI values of 30 kg/m2 and 25 kg/m2, respectively, for Caucasians. In the future, the optimal cut-off levels for obesity and abdominal obesity may require adjustment as the demographic characteristics of the Korean population change. In addition, development of more valid indicators that better reflect health risks of obesity is needed.

Cut-Off Values for Visceral Fat Area Identifying Korean Adults at Risk for Metabolic Syndrome

Background

Cut-off values for visceral fat area (VFA) measured by computed tomography (CT) for identifying individuals at risk of metabolic syndrome (MetS) have not been clearly established in Korean adults, particularly for large populations. We aimed to identify optimal VFA and waist circumference (WC) cut-off values and compare the ability of VFA and WC to predict the presence of ≥2 metabolic risk factors.

Methods

We included 36,783 subjects aged 19–79 years undergoing abdominal fat CT during regular health checkups between January 2007 and February 2015 in Seoul. The risk factors for MetS except WC were based on the International Diabetes Federation criteria. Receiver operating characteristic curve analyses were used to determine the appropriate VFA and WC cut-off values for MetS.

Results

VFA was a more significant predictor of metabolic risk factors than WC and body mass index (BMI). The optimal cut-off values for VFA and WC were 134.6 cm² and 88 cm for men and 91.1 cm² and 81 cm for women, respectively. We estimated age-specific cut-off values for VFA, WC, and BMI. VFA cut-off values increased with age, particularly among women.

Conclusion

This large population study proposed the cut-off values for VFA and WC for identifying subjects at risk of MetS among Korean adults. For more accurate diagnosis, different age-specific cut-off values for VFA and WC may be considered.

Visceral Fat Mass Has Stronger Associations with Diabetes and Prediabetes than Other Anthropometric Obesity Indicators among Korean Adults

PURPOSE

This study determined which obesity measurement correlates the best with diabetes and prediabetes.

MATERIALS AND METHODS

This cross-sectional study enrolled 1603 subjects (611 men, 992 women; age 30-64 years) at the Cardiovascular and Metabolic Diseases Etiology Research Center. Body mass index, waist circumference, waist-height ratio, waist-hip ratio, waist-thigh ratio, and visceral fat were used as measures of obesity. Visceral fat was acquired using dual-energy X-ray absorptiometry (DXA). The prevalences of diabetes and prediabetes were defined using the criteria in the American Diabetes Association 2015 guidelines.

RESULTS

After adjusting for age and other potential confounding factors, participants with a visceral fat mass in the upper 10th percentile had a higher odds ratio (OR) for diabetes and prediabetes than the upper 10th percentile of other adiposity indices [men, OR=15.9, 95% confidence interval (CI)=6.4-39.2; women, OR=6.9, 95% CI=3.5-13.7]. Visceral fat mass also had the highest area under the curve with diabetes and prediabetes in both men (0.69, 95% CI=0.64-0.73) and women (0.70, 95% CI=0.67-0.74) compared to other anthropometric measurements of obesity.

CONCLUSION

Visceral fat mass measured using DXA is an indicator of diabetes or prediabetes, due to its ability to differentiate between abdominal visceral and subcutaneous fat.

Comparison of Visceral Fat Measures with Cardiometabolic Risk Factors in Healthy Adults

We aimed to evaluate the associations of visceral adiposity with cardiometabolic risk factors in normal subjects with integrated ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). A total of 58 normal subjects who underwent ¹⁸F-FDG PET/CT scan for cancer screening were included in this study. Volume and average Hounsfield unit (HU) of visceral adipose tissue (VAT) was measured from CT components of integrated PET/CT. Standardized uptake values (SUVmax) of liver, spleen, lumbar spine and ascending aorta (AA) were measured from PET components of integrated PET/CT. Body mass index (coefficient 78.25, p = 0.0259), glucose (37.62, p<0.0001), insulin (348.90, p = 0.0011), logarithmic transformation of homeostatic model assessment index-insulin resistance (-2118.37, p = 0.0007), and VAT HU (-134.99, p<0.0001) were independently associated with VAT volume. Glucose (0.1187, p = 0.0098) and VAT volume (-0.004, p<0.0001) were found to be associated with VAT HU. Both VAT volume and VAT HU of whole abdominal cavity is significantly associated with cardiometabolic risk factors.

Clinical utility of visceral adipose tissue for the identification of cardiometabolic risk in white and African American adults

BACKGROUND

Visceral adipose tissue (VAT) has been identified as a harmful fat depot, and sex and race differences in VAT have been reported in white and African Americans.

OBJECTIVES

We determined the clinical utility of VAT in the identification of individuals at elevated cardiometabolic risk in white and African American adults and compared the clinical utility with measures obtained by using dual-energy X-ray absorptiometry (DXA) and anthropometric measures.

DESIGN

The sample included 429 white women, 311 African American women, 406 white men, and 100 African American men who were 18-74 y of age. VAT was measured by using computed tomography, fat mass (FM) and percentage of body fat were measured by using DXA, and waist circumference (WC) and BMI were assessed. Receiver operating characteristic curves were used to compare the utility of measures in the identification of participants in the upper quintile of a continuous score derived from principal components analysis of fasting glucose, HDL cholesterol, triglycerides, and blood pressure.

RESULTS

The clinical utility of measures varied across sex-by-race groups. In the overall sample, the areas under the curve were significantly higher for VAT and WC in comparison with the other indicators. Identified VAT thresholds were higher in white men (140 cm(2)) and women (141 cm(2)) than in African American men (82 cm(2)) and women (97 cm(2)).

CONCLUSIONS

VAT and WC showed greater clinical utility than did other obesity measures. Because of the complexity of measuring VAT, the use of WC is recommended for the identification of adults with elevated cardiometabolic risk factors. The Pennington Center Longitudinal Study was registered at clinicaltrials.gov as NCT00959270.

Gender differences in diagnostic values of visceral fat area and waist circumference for predicting metabolic syndrome in Koreans

Abdominal fat accumulation is known to be strongly implicated in development of metabolic syndrome (MetS). We examined diagnostic values of obesity-related parameters in 95 men and 185 women, and we determined optimal cutoff values of visceral fat area (VFA) and waist circumference (WC) for predicting the presence of multiple non-adipose components of MetS. Receiver operating characteristic (ROC) curve analysis revealed that VFA was the best indicator of MetS. WC and VFA exhibited similar diagnostic values for men and postmenopausal women, whereas WC was inferior to VFA for premenopausal women (area under ROC curve of VFA and WC was 0.76 and 0.52, respectively; P < 0.001). Optimal cutoff points of VFA and WC for predicting MetS were 136 cm(2) and 89 cm in men and 95 cm(2) and 82 cm in women, respectively. Subjects with VFA and WC above these cutoff values exhibited increased insulin resistance and increased carotid intima-media thickness. In conclusion, WC has a diagnostic value similar to VFA for predicting MetS in men and postmenopausal women, but not in premenopausal women. Further studies are necessary to develop a simple clinical parameter that reflects visceral fat in premenopausal women.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Optimal waist circumference cutoff value reflecting insulin resistance as a diagnostic criterion of metabolic syndrome in a nondiabetic Korean population aged 40 years and over: the Chungju Metabolic Disease Cohort (CMC) study

PURPOSE

We aimed at determining the cutoff value of waist circumference with respect to its ability to reflect insulin resistance in a Korean population.

MATERIALS AND METHODS

A total of 8,817 subjects aged 40 years and over were analyzed. Insulin resistant individuals were defined as those who had the highest quartile value of the homeostasis model assessment of insulin resistance (HOMA-IR) in a non-diabetic population. Receiver operating characteristic (ROC) curve analysis and multiple logistic regression analysis were applied.

RESULTS

The cutoff value of waist circumference reflecting insulin resistance from the ROC analysis was 84.4 cm for men and 80.6 cm for women. Sensitivity and specificity were 70.0% and 54.2% in men and 71.1% and 59.3% in women, respectively. After being controlled for other covariates, the odds ratio for the risk of insulin resistance using < 70 cm of waist circumference as a reference increased significantly in the category of 85.0-89.9 cm for men and 80.0-84.9 cm for women. In addition, statistically significant associations were consistently observed over the category of 85.0-89.9 cm for men and 80.0-84.9 cm for women.

CONCLUSION

The optimal cutoff value for waist circumference reflecting insulin resistance is considered to be 85 cm for men and 80 cm for women, suggesting that the Asian criterion of abdominal obesity (90 cm for men and 80 cm for women) as a component of metabolic syndrome (MetS) might not be applicable for middle-aged to older men in Korea.

The cutoff values of visceral fat area and waist circumference for identifying subjects at risk for metabolic syndrome in elderly Korean: Ansan Geriatric (AGE) cohort study

Background

In Korea, the cutoff values of waist circumference (WC) for the identification of metabolic syndrome (MetS) were suggested to be 90 cm for men and 85 cm for women based on the analysis mainly in middle-aged adults. As aging is associated with increased fat, especially abdominal visceral fat, the cutoff value of WC may differ according to age. In addition, the usefulness of visceral abdominal fat area (VFA) to predict MetS in the elderly has not been studied yet. We aimed to suggest WC and VFA criteria and to compare the predictability of WC and VFA to identify people at risk for MetS.

Methods

A total of 689 elderly subjects aged ≥63 years (308 men, 381 women) were chosen in this cross-sectional study from an ongoing, prospective, population-based study, the Ansan Geriatric (AGE) cohort study. VFA was measured by single slice abdominal computed tomography scanning. The metabolic risk factors except WC (plasma glucose, blood pressure, serum triglycerides and HDL cholesterol levels) were defined using modified NCEP-ATP III criteria. We estimated the accuracy of VFA and WC for identifying at least two of these factors by receiver operating characteristic (ROC) curve analysis.

Results

Two hundred three of 308 men and 280 of 381 women had ≥2 metabolic risk factors. The area under the ROC curve (AUC) value for VFA to predict the presence of ≥2 metabolic risk factors was not significantly different from that for WC (men, 0.735 and 0.750; women, 0.715 and 0.682; AUC values for VFA and WC, respectively). The optimal cutoff points for VFA and WC for predicting the presence of ≥2 metabolic risk factors were 92.6 cm² and 86.5 cm for men and 88.9 cm² and 86.5 cm for women.

Conclusion

WC had comparable power with VFA to identify elderly people who are at risk for MetS. Elderly Korean men and women had very similar cutoff points for both VFA and WC measurements for estimating the risk of MetS. Age-specific cutoff point for WC might be considered to identify subjects at risk for MetS.

Adipogenic risk factor differences between Korean and white adults--potential role of plasma free fatty acid and adiponectin

Asian adults are at greater risk for metabolic abnormalities (insulin resistance, dyslipidemia) at the same body mass index (BMI) than are whites. Elevated free fatty acids (FFA) and decreased adiponectin are linked with these same metabolic abnormalities. We tested the hypothesis that fasting plasma FFA are greater and adiponectin concentrations are lower in Korean than white adults matched for age, sex, and BMI. Plasma FFA and adiponectin concentrations were analyzed using a microfluorometric assay and radioimmunoassay, respectively. Fasting plasma FFA concentrations were not different (P = .51) between Korean and white subjects (208 [183-232] vs 215 [168-262] mumol/L, median and 95% confidence interval). Despite similar body composition in the 2 groups, the plasma adiponectin concentrations in Koreans were significantly lower than those in whites in men, women, and total subgroups (adjusted mean +/- SEM: 4.9 +/- 0.8 vs 9.1 +/- 0.8 microg/mL, P = .004; 8.9 +/- 1.0 vs 13.2 +/- 1.0 microg/mL, P = .006; and 6.5 +/- 0.6 vs 11.1 +/- 0.6 microg/mL, P <or= .001, respectively) after adjustment for differences in height, weight, and fat-free mass as covariates. Men had lower plasma adiponectin concentrations than women in both Korean (P = .041) and Western adults (P < .001). Plasma adiponectin levels are lower in Korean than age-, sex-, and body mass index-matched white adults, whereas fasting plasma FFA are not different. To the extent that adipogenic factors account for ethnic differences in metabolic disease risk, our data suggest that differences in the regulation of adiponectin may predispose toward greater metabolic abnormalities in Asians than whites at comparable BMI levels.