Abdominal Obesity Index as an Alternative Central Obesity Measurement During a Physical Examination

Abstract

Although BMI (body mass index) has been widely used to determine whether an individual is underweight, normal weight, overweight, or obese, its clinical usefulness for obesity study has been called into question because it does not specifically describe body fat content and distribution and has limited relevance to central obesity, which is most relevant to health risks. Although imaging techniques are used to determine central obesity, they are expensive and are thus not used in a routine physical examination of patients in medical offices. Developing an easy-to-use ABOI (Abdominal Obesity index) to measure central obesity during a physical examination. ABOI is an index utilized to assess central obesity of patients. To determine ABOI, two measurements are taken from the torso; the outer circumference of the thoracic segment, C1, at the xiphoid process and the outer circumference of the abdominal segment, C2, at the point of largest girth. The volume of the abdominal segment is divided by the volume of the thoracic segment to derive ABOI (V2/V1 = [C2]2/[C1]2). Thus, ABOI is the square of the ratio of the circumference of the abdominal segment to the circumference of the thoracic segment of the torso. Moreover, the ABOI does not concern total body weight, body height, or body shape (e.g. “apple-shaped” or “pear-shaped” body types). Instead, ABOI specifically highlights central obesity. We randomly recruited 282 subjects, ages 20-90 years, at a community health service center in Beijing, China, and determined their ABOI and BMI values. The mean (standard deviation) BMI for the female and male subjects is, respectively, 24.24 kg/m2 (3.35) and 24.86 kg/m2 (3.25). For ABOI, mean (standard deviation) is 1.17 (0.16) and 1.01 (0.13) for females and males, respectively. There is no strict relationship between ABOI and BMI in the context of obesity as defined by high BMI values, and ABOI appears to be a more specific measure of central obesity than BMI. ABOI is a useful and distinct independent measurement of central obesity, and ABOI (possibly in combination with the waist-to-height ratio) appears to be a more specific way to assess central obesity during a physical examination.