Visceral obesity and cardiometabolic risks: lessons from the VACTION-J study

Visceral fat area and cardiometabolic risk: The Kardiovize study

BACKGROUND

Visceral fat is associated with adiposity-based complications. Bioimpedance measurement allows estimation of visceral fat area (VFA) in an easy manner. However, a validated cut-off value for VFA by bioimpedance associated with cardiometabolic risk is lacking in European population.

AIM

To determine cut-off values of VFA measured via bioimpedance associated with cardiometabolic risk.

METHODS

Random cross-sectional Czech population-based sample of 25-64 years old subjects. Receiver Operating Characteristic (ROC) curves were used and the area under the curve (AUC), sensitivity, and specificity were calculated. The Cardiometabolic Disease Staging System (CMDS) was used to classify cardiometabolic risk: Stage 1 - 1 or 2 metabolic syndrome (MetS) components, without impaired fasting glucose (IFG); Stage 2 - MetS or IFG; Stage 3 - MetS with IFG; Stage 4 - type 2 diabetes and/or cardiovascular disease.

RESULTS

2052 participants (54.5% females, median age 49 years) were included. Median VFA (inter-quartile range) were 82.2 cm² (54.8) in men and 89.8 cm² (55.6) in women. The best VFA cut-offs associated with Stage 1 in men and women were 71 cm² (sensitivity = 0.654; specificity = 0.427) and 83 cm² (sensitivity = 0.705; specificity = 0.556) ; Stage 2: 84 cm² (sensitivity = 0.673; specificity = 0.551) and 98 cm² (sensitivity = 0.702; specificity = 0.628) ; Stage 3: 90 cm² (sensitivity = 0.886; specificity = 0.605) and 109 cm² (sensitivity = 0.755; specificity = 0.704); Stage 4: 91 cm² (sensitivity = 0.625; specificity = 0.611) and 81 cm² (sensitivity = 0.695; specificity = 0.448), respectively.

CONCLUSION

A cut-off value of VFA of 71 cm² in men and 83 cm² in women exhibited the earliest stage of cardiometabolic risk, and 90 cm² in men and 109 cm² in women showed the best performance to detect risk.

Quantitative Assessment of Visceral Obesity and Postoperative Colon Cancer Outcomes

BACKGROUND

Quantitative computed tomography (CT) assessment of visceral adiposity may be superior to body mass index (BMI) as a predictor of surgical morbidity. We sought to examine the association of CT measures of obesity and BMI with short-term postoperative outcomes in colon cancer patients.

METHODS

In this retrospective study, 110 patients treated with colectomy for stage I-III colon cancer were classified as obese or non-obese by preoperative CT-based measures of adiposity or BMI [obese: BMI ≥ 30 kg/m², visceral fat area (VFA) to subcutaneous fat area ratio (V/S) ≥0.4, and VFA > 100 cm²]. Postoperative morbidity and mortality rates were compared.

RESULTS

Obese patients, by V/S and VFA but not BMI, were more likely to be male and have preexisting hypertension and diabetes. The overall complication rate was 25.5%, and there were no mortalities. Obese patients by VFA (with a trend for V/S but not BMI) were more likely to develop postoperative complications as compared to patients classified as non-obese: VFA (30.5 vs.10.7%, p = 0.03), V/S (29.2 vs. 9.5%, p = 0.05), and BMI (32.4 vs. 21.9%, p = 0.23).

CONCLUSIONS

Elevated visceral obesity quantified by CT is associated with the presence of key metabolic comorbidities and increased postoperative morbidity and may be superior to BMI for risk stratification.

Clinical significance of visceral adiposity assessed by computed tomography: A Japanese perspective

Abdominal obesity, rather than total amount of fat, is linked to obesity-related disorders. Visceral adiposity is an important component of obesity-related disorders in Japanese individuals with a mild degree of adiposity compared with Western subjects. In 1983, our group reported techniques for body fat analysis using computed tomography (CT) and established the concept of visceral fat obesity in which intra-abdominal fat accumulation is an important factor in the development of obesity-related complications, such as diabetes, lipid disorders, hypertension and atherosclerosis. Our group also established ideal imaging conditions for determining abdominal fat area at the umbilical level CT scan. Visceral fat area (VFA) measured in a single slice at L4 level correlated significantly with the total abdominal visceral fat volume measured on multislice CT scan. In a large-scale study of a Japanese population, the mean number of obesity-related cardiovascular risk factors (hypertension, low high-density lipoprotein cholesterolemia and/or hypertriglyceridemia, and hyperglycemia) was greater than 1.0 at 100 cm² of VFA, irrespective of gender, age and body mass index. Our group also demonstrated that reduction of visceral fat accumulation subsequent to voluntary lifestyle modification, “Hokenshido”, correlated with a decrease in the number of obesity-related cardiovascular risk factors. It is important to select the most appropriate subjects from the general population (e.g., non-obese subjects with a cluster of risk factors for the metabolic syndrome) that are most suitable for body weight reduction, with the goal of preventing atherosclerotic cardiovascular diseases.