Body volume index: time to replace body mass index?
Abd Tahrani2, Kristien Boelaert2, Richard Barnes3, Suzanne Palin2, Annmarie Field1, Helen Redmayne1, Lisa Aytok3 & Asad Rahim1
Background: Body Mass Index (BMI) and waist circumference (WC) are currently used to assess obesity. BMI and WC do not take into account fat/muscle distribution or allow for distinctions between gender, age or ethnicity. WC reflects abdominal fat distribution more accurately, but is operator-dependant and variable in terms of reproducibility. BVI is a totally new, reproducible and novel concept using a 3D body scanner and appropriate software, to measure total body and 8 body segment volumes, such as the abdomen. Thus, obesity based on individual body shape may be assessed.
Aims: To evaluate the use of BVI in assessing obesity and its relation to BMI and WC.
Methods: Fifty-three obese/overweight volunteers were recruited. Data collected included age, gender, BMI and WC (manually). Subjects underwent 3D body scanning and had their BVI and WC calculated using data generated from the 3D scans.
Results: Data presented as median (range). 53 patients (77% males) were included. BMI was 30.5 (26.436.1) kg/m2;WC was 98 (73.5119.5) cm. Total BVI was 76 (6297) litres. Trunk volume was 41.8 (29.759.1) litres. Correlations between BVI (total and trunk), BMI and WC are summarised in Table 1. Automated and manual WC correlated significantly with total BVI and trunk volume (P<0.0001). BMI also correlated with total and trunk BVI (P<0.001).
|Variables||Correlation coefficient||P value|
|BMI and Total BVI||0.488||<0.001|
|BMI and automated WC||0.497||<0.001|
|BMI and trunk volume||0.337||0.014|
|Manual and automated WC||0.509||<0.001|
|Manual WC and BVI||0.620||<0.001|
|Manual WC and trunk volume||0.654||<0.001|
Conclusions: BVI, total and trunk, and automated WC measurements correlated significantly with BMI and manual WC measurements in overweight/obese subjects. BVI is a valid new method in assessing overweight/obesity and more reproducible and less operator-dependant than BMI and WC. Further studies to assess cut-off values to define overweight/obesity using BVI and the correlation between BVI and obesity-related complications are needed.