Estimation of abdominal fat compartments by bioelectrical impedance: the validity of the ViScan measurement system in comparison with MRI.

BACKGROUND/
OBJECTIVES: Abdominal obesity, more specifically increased intra-abdominal adipose tissue, is strongly associated with increased risk of metabolic disease. Bioelectrical impedance analysis (BIA) has been proposed as a potential method of determining individual abdominal fat compartments in the form of the commercially available ViScan measurement system (Tanita Corporation), but it has yet to be independently validated. The objective of this study was to analyse the validity of the ViScan to assess adult abdominal adiposity across a range of body fatness. SUBJECTS/
METHODS: This was a cross-sectional study with 74 participants (40 females and 34 males with body mass index (BMI) between 18.5 and 39.6 kg/m(2)). Total abdominal adipose tissue, subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) were measured by magnetic resonance imaging (MRI). In addition, intra-hepatocellular lipid was obtained by magnetic resonance spectroscopy. Estimates of abdominal adiposity (total and compartmental) were obtained from BIA and anthropometry.
RESULTS: ViScan-derived percentage trunk fat strongly and significantly related with total abdominal adipose tissue and SAAT in both lean and overweight/obese individuals, and categorized individuals reliably in terms of total abdominal fat. ViScan-derived 'visceral' fat correlated significantly with IAAT but the strength of this relationship was much weaker in overweight/obese individuals, particularly those with higher SAAT, leading to less reliable classification of individuals for IAAT.
CONCLUSIONS: The ViScan may serve as a useful tool for predicting total abdominal fat, but prediction of visceral fat (IAAT) may be limited, especially in abdominally obese individuals.