[Abdomen specific bioelectrical impedance analysis (BIA) methods for evaluation of abdominal fat distribution].

Two novel bioelectrical impedance analysis (BIA) methods have been developed recently for evaluation of intra-abdominal fat accumulation. Both methods use electrodes that are placed on abdominal wall and allow evaluation of intra-abdominal fat area (IAFA) easily without radiation exposure. Of these, "abdominal BIA" method measures impedance distribution along abdominal anterior-posterior axis, and IAFA by BIA method(BIA-IAFA) is calculated from waist circumference and the voltage occurring at the flank. Dual BIA method measures impedance of trunk and body surface at the abdominal level and calculates BIA-IAFA from transverse and antero-posterior diameters of the abdomen and the impedance of trunk and abdominal surface. BIA-IAFA by these two BIA methods correlated well with IAFA measured by abdominal CT (CT-IAFA) with correlatipn coefficient of 0.88 (n = 91, p < 0.0001) for the former, and 0.861 (n = 469, p < 0.01) for the latter. These new BIA methods are useful for evaluating abdominal adiposity in clinical study and routine clinical practice of metabolic syndrome and obesity.

Intra-abdominal fat area is a predictor for new onset of individual components of metabolic syndrome: MEtabolic syndRome and abdominaL ObesiTy (MERLOT study).

OBJECTIVE: To investigate the significance of intra-abdominal fat area (IAFA) on new onset of individual components of the metabolic syndrome: high blood pressure, dyslipidemia, or hyperglycemia. METHODS: We conducted a longitudinal study using checkup data of a hospital from 1994 to 2010. Of 25,255 subjects, we examined 1,380 Japanese, who underwent computed tomography to measure IAFA and had no metabolic syndrome components at baseline. RESULTS: During 3.6 years of the mean follow-up period, one of metabolic syndrome components occurred in 752 subjects. Of three components, high blood pressure was more prevalent. The multiple Cox regression analysis disclosed that IAFA is significantly associated with onset of metabolic syndrome components (HR: 1.05 per 10 cm(2), 95%CI: 1.03-1.07). This finding was independent of BMI, and significant even in non-obese individuals with body mass index <25 kg/m(2). CONCLUSIONS: MERLOT study demonstrates that IAFA is an independent predictor for new onset of individual components of the metabolic syndrome, even in non-obese healthy Japanese.

[Concept and classification of obesity].

Obesity is recognized as a disease when it is associated with current or future health problems. The association of obesity with hypertension, glucose intolerance, and lipid metabolism disorder is diagnosed as metabolic syndrome since it tends to cause arteriosclerotic diseases. Obesity is important since it is pandemic throughout the earth. In this review we explain the concept and classification of obesity. We discuss the disease basis of obesity and metabolic syndrome, especially from the standpoint of adipotoxicity.

Early changes of abdominal adiposity detected with weekly dual bioelectrical impedance analysis during calorie restriction.

OBJECTIVE: To elucidate early change of intra-abdominal fat in response to calorie restriction in patients with obesity by weekly evaluation using a dual bioelectrical impedance analysis (Dual BIA) instrument. METHODS: For 67 Japanese patients with obesity, diabetes, or metabolic syndrome, intra-abdominal fat area (IAFA), initially with both Dual BIA and computed tomography (CT), and in subsequent weeks of calorie restriction, with Dual BIA were measured. RESULTS: IAFA by Dual BIA (Dual BIA-IAFA) correlated well with IAFA by CT (CT-IAFA) in obese patients (r = 0.821, P < .0001, n = 67). Ten males and 9 females (age 49.0 ± 14.4 years, BMI 33.2 ± 7.3 kg/m2) lost more than 5% of baseline body weight (BW) in 3 weeks, and their Dual BIA-IAFA, BW, and WC decreased by 18.9%, 5.3%, and 3.8%, respectively (P < .05, ANCOVA). CONCLUSION: Dual BIA instrument could detect the weekly change of Dual BIA-IAFA under calorie restriction in obese patients and demonstrated a substantially larger change of IAFA compared with changes of BW and WC in early weeks. This observation corroborates the significance of evaluating IAFA as a biomarker for obesity, and indicates the clinical usefulness of the Dual BIA instrument.