Measurement Of Visceral Fat Area Research Articles

Contribution of Visceral Fat Accumulation to the Risk Factors for Atherosclerosis in Non-Obese Japanese

To clarify the contributions of visceral fat tissue (VAT) mass deposition to the accumulation of risk factors for atherosclerosis in normal weight subjects. We investigated the relationship between VAT accumulation and both risk factors and waist circumference in non-obese subjects. In the 955 normal weight Japanese subjects (782 men and 173 women), visceral fat area (VFA), subcutaneous fat area (SFA) and waist circumference were measured through computed tomography. Total cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, uric acid, fasting blood glucose, and 2-hour postprandial glucose in the oral glucose tolerance test (OGTT) were measured to assess the risk factors for atherosclerosis. In both men and women with normal body weight, VFA was correlated with total cholesterol (r=0.78 and r=0.71, respectively), HDL cholesterol (r=-0.89 and r=-0.82, respectively), triglyceride (r=0.72 and r=0.91, respectively), uric acid (r=0.71 and r=0.69, respectively), fasting blood glucose (r=0.84 and r=0.82, respectively), OGTT 2-hour postprandial glucose (r=0.75 and r=0.50, respectively), and systolic (r=0.93 and r=0.73, respectively) and diastolic (r=0.91 and r=0.73, respectively) blood pressure. The average number of risk factors was also correlated with VFA both in men (r=0.88, p=0.005) and women (r=0.91, p=0.003) with normal body weight. Based on the results of the multiple regression analyses, among VFA, SFA, body mass index (BMI) and age, VFA was considered to be the most important predictor for explaining the average number of risk factors. We also demonstrated that VFA was correlated with the waist circumference in normal weight men (r=0.74) and women (r=0.59). In normal weight subjects, the waist circumference equivalent to more than 1.0 of the average number of risk factors was 81 cm in men and 89 cm in women. VAT accumulation itself plays a role as a risk factor for atherosclerosis irrespective of BMI, and measurement of VFA may be more important than that of BMI for predicting the presence of risk factors in normal weight subjects. Measurement of waist circumference also might be important for assessing the possibility of VAT accumulation leading to atherosclerosis.

Reproducibility of fat area measurements in young, non-obese subjects by computerized analysis of magnetic resonance images.

To assess reproducibility, expressed as both inter-observer variability and intra-observer variability, of fat area measurements on images obtained by magnetic resonance (MR); to compare variability between fat area measurements, calculated from a single image per body region and from the average fat area of three images, and to determine reproducibility of image acquisition at the abdominal level. Thirty young, non-obese subjects (reproducibility of image analysis) and nine young, non-obese subjects (reproducibility of image acquisition). Three MR images at the level of the abdomen (in 30 subjects) and at the level of the hip and thigh (in 14 of them). Quantification of subcutaneous fat depots (abdomen, hip and thigh) and visceral fat depots using an image-analyzing computer program. Assessment of variability of image analysis for fat area measurements between two observers and within observers. Assessment of reproducibility of image acquisition at the abdominal level (in nine subjects). Subcutaneous fat areas in all body regions were quantified with coefficients of variation (CV) ranging from only 2.1%-4.9%. By contrast, visceral fat area measurements showed markedly higher CVs (range: 9.4%-17.6%). Moreover, relative variability was much larger in small visceral fat areas (CVs up to 25.6%). The majority of CVs, calculated for intra-observer variability and calculated from the average fat area measurements of three images, was lower than calculated for inter-observer variability and for one single image, respectively. In particular, for the visceral fat depot, this reduction in variability had practical consequences for the number of subjects required for a study. Variation of repeated image acquisition was in the same range as variation of repeated measurements on the same image. One image per body site is sufficient to obtain a reliable estimate of subcutaneous fat depots. For estimations of the visceral fat depot, the average area measurements of three images reduces variability and increases statistical power. The availability of one single experienced observer during a study adds to accuracy.