The relation between visceral fat measurement and torso level--is one level better than another? The Atherosclerosis Risk in Communities Study, 1990-1992.

Intraabdominal fat (IAF) area is often measured indirectly in epidemiologic studies. The authors recruited 147 participants from the second examination (1990-1992) of the Atherosclerosis Risk in Communities Study to examine IAF area and determine whether there were differences in IAF area and distribution by location. Magnetic resonance imaging was used to image four 10-mm slices between the second and fourth lumbar vertebrae by an inverse recovery method, and IAF was calculated from each image. The authors constructed gender-specific mixed models with IAF area as the outcome and the location of imaging along the torso as the independent variable, using random intercepts to account for between-person variation in IAF area. The torso location of IAF measurement was a significant predictor of IAF area in both men (p = 0.02) and women (p < 0.0001) after adjustment for body mass index. A significant positive interaction between age and location was seen in men, with increasing IAF area moving down the torso with older ages. Using magnetic resonance imaging, location along the torso yields different IAF areas and distributions independently of body mass index in both genders, with measurement at the second lumbar vertebra (slightly above the umbilicus) capturing the largest amount of IAF. Studies that attempt to link IAF with cardiovascular disease risk factors should consider measurement location to accurately capture the association.