Age and sex influence the relationship between waist circumference and abdominal fat distribution measured by bioelectrical impedance

Waist circumference (WC) is a subrogate measurement of abdominal visceral fat (AVF) with a different normal threshold for men and women. However, age plays an important role in the relationship of WC with AVF. The hypothesis of the present work was that the adjustment of the WC, not only by sex but also by age, would improve WC prediction of AVF as measured by a new bioelectrical impedance (BIA) methodology. The study was carried out in 311 subjects (178 men and 133 women) with a body mass index between 18 and 35 kg/m2. Abdominal fat composition was measured by BIA by using a new device recently developed specifically for the measurement of abdominal fat compartments (ViScan AB140;Omron Corp, Tokyo, Japan). Clinical, anthropometric, and biochemical data were also collected. There was a high correlation of WC with total abdominal fat and AVF in all age ranges and for both fat depots, which decreased with age in men but remained more stable in women. Age independently influenced the level of AVF in women and in those subjects with normal WC, increasing by 0.32 and 0.47 for each decade of age, respectively. In conclusion, age plays an important role in the association between WC and AVF with a high correlation existing in all age ranges. A specific BIA method that measures abdominal composition would be useful in women and in those subjects with normal WC as an indicator of AVF.