TY - JOUR

T1 - Inverted BMI rather than BMI is a better proxy for percentage of body fat

AU - Nevill, AM

AU - Stavropoulos-Kalinoglou, A

AU - Metsios, GS

AU - Koutedakis, Y

AU - Holder, Roger

AU - Kitas, GD

AU - Mohammed, Mohammed

PY - 2011/11/1

Y1 - 2011/11/1

N2 - Background: Percentage of body fat (BF%) is a known risk factor for a range of healthcare problems but is difficult to measure. An easy to measure proxy is the weight/height(2) ratio known as the Body Mass Index (BMI kg/m(2)). However, BMI does have some inherent weaknesses which are readily overcome by its inverse iBMI (1000/BMI, cm(2)/kg).
Methods: The association between BF% and both BMI and iBMI together with their distributional properties was explored using previously published data from healthy (n = 2993) and diseased populations (n = 298).
Results: BMI is skewed whereas iBMI is symmetrical and so is better approximated by the normal distribution. The relationship between BF% and BMI is curved, but that of iBMI and BF% is linear and thus iBMI explains more of the variation in BF% than BMI. For example a unit increase in BMI for a group of thin women represents an increase of 2.3% in BF, but for obese women this represents only a 0.3% increase in BF-a 7-fold difference. The curvature stems from body mass being the numerator in BMI but the denominator in BF% resulting in a form of hyperbolic curve which is not the case with iBMI. Furthermore, BMI and iBMI have different relationships (interaction) with BF% for men and women, but these differences are less marked with iBMI.
Conclusions: Overall, these characteristics of iBMI favour its use over BMI, especially in statistical models.

AB - Background: Percentage of body fat (BF%) is a known risk factor for a range of healthcare problems but is difficult to measure. An easy to measure proxy is the weight/height(2) ratio known as the Body Mass Index (BMI kg/m(2)). However, BMI does have some inherent weaknesses which are readily overcome by its inverse iBMI (1000/BMI, cm(2)/kg).
Methods: The association between BF% and both BMI and iBMI together with their distributional properties was explored using previously published data from healthy (n = 2993) and diseased populations (n = 298).
Results: BMI is skewed whereas iBMI is symmetrical and so is better approximated by the normal distribution. The relationship between BF% and BMI is curved, but that of iBMI and BF% is linear and thus iBMI explains more of the variation in BF% than BMI. For example a unit increase in BMI for a group of thin women represents an increase of 2.3% in BF, but for obese women this represents only a 0.3% increase in BF-a 7-fold difference. The curvature stems from body mass being the numerator in BMI but the denominator in BF% resulting in a form of hyperbolic curve which is not the case with iBMI. Furthermore, BMI and iBMI have different relationships (interaction) with BF% for men and women, but these differences are less marked with iBMI.
Conclusions: Overall, these characteristics of iBMI favour its use over BMI, especially in statistical models.

KW - body fat

KW - inverted body mass index

KW - Body mass index

KW - transformation

U2 - 10.3109/03014460.2011.606832

DO - 10.3109/03014460.2011.606832

M3 - Article

C2 - 21846303

SN - 0301-4460

VL - 38

SP - 681

EP - 684

JO - Annals of Human Biology

JF - Annals of Human Biology

IS - 6

ER -