http://dx.doi.org/10.3349/ymj.2014.55.4.1028 Original Article pISSN: 0513-5796, eISSN: 1976-2437 Yonsei Med J 55(4):1028-1035, 2014 Comparison of the Body Adiposity Index to Body Mass Index in Korean Women Yeon-Ah Sung, Jee-Young Oh, and Hyejin Lee Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea. Received: August 30, 2013 Purpose: Obesity is a major public health issue and is associated with many meta- Revised: November 13, 2013 bolic abnormalities. Consequently, the assessment of obesity is very important. A Accepted: November 25, 2013 new measurement, the body adiposity index (BAI), has recently been proposed to Corresponding author: Dr. Hyejin Lee, provide valid estimates of body fat percentages. The objective of this study was to Department of Internal Medicine, compare the BAI and body mass index (BMI) as measurements of body adiposity Ewha Womans University School of Medicine, Ewha Womans University Mokdong Hospital, and metabolic risk. Materials and Methods: This was a cross-sectional analysis 1071 Anyangcheon-ro, Yangcheon-gu, performed on Korean women. The weight, height, and hip circumferences of 2950 Seoul 158-710, Korea. women (mean age 25±5 years old, 18--39 years) were measured, and their BMI Tel: 82-10-2650-2846, Fax: 82-2-2650-2846 and BAI [hip circumference (cm)/height (m)1.5-18] values were calculated. Bio- E-mail: [email protected] electric impedance analysis was used to evaluate body fat content. Glucose toler- ∙ The authors have no financial conflicts of ance status was assessed with a 75-g oral glucose tolerance test, and insulin sensi- interest. tivity was estimated with the insulin sensitivity index. Results: BMI was more significantly correlated with fat mass and fat percentage. Additionally, BMI was also more significantly associated with metabolic parameters, including fasting glucose, post-load 2-h glucose, fasting insulin, post-load 2-h insulin, triglycerides, and high density lipoprotein cholesterol than BAI. Receiver operating characteris- tic curve analysis revealed that BMI was a better tool for predicting body fat per- centage than BAI. Insulin sensitivity and metabolic syndrome were more signifi- cantly associated with BMI than with BAI. Conclusion: In Korean women, the current BMI-based classifications for obesity might be superior to BAI-based mea- surements for determining obesity and predicting metabolic risk. Key Words: Body adiposity index, body mass index, obesity INTRODUCTION Obesity is a common condition and is increasing in prevalence worldwide, includ- ing in Asia.1 Obesity is defined as a state of excess adipose tissue, and it is associ- © Copyright: ated with numerous chronic health conditions, such as type 2 diabetes mellitus, Yonsei University College of Medicine 2014 cardiovascular disease, hypertension, and cancer. Moreover, mortality rates are in- This is an Open Access article distributed under the creased in obese individuals.2-4 Consequently, identifying obesity to estimate the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/ risks of associated diseases is a major health concern. licenses/by-nc/3.0) which permits unrestricted non- commercial use, distribution, and reproduction in any Obesity is characterized by excess body fat, something difficult to measure. In- medium, provided the original work is properly cited. creased body fat is usually accompanied by increased total body mass; therefore, 1028 Yonsei Med J http://www.eymj.org Volume 55 Number 4 July 2014 Body Adiposity Index to Body Mass Index indices of relative weight are commonly used to diagnose BAI would accurately represent body fat and metabolic risk obesity. One of the most commonly used indices of relative in Korean women. weight is body mass index (BMI), which is an accepted in- dex to characterize obesity in individuals and most widely used in epidemiological studies.5 BMI is very useful; how- MATERIALS AND METHODS ever, despite its widespread use, it is only a surrogate mea- surement of body fat, and it does not provide an accurate Subjects measurement of body composition,6 and may be influenced The present cross-sectional study was carried out on 2950 by age, sex, and ethnicity.7 Moreover, adipose tissue is re- Korean women (aged 18--39 years old) recruited from Ewha sponsible for the majority of obesity-associated diseases; Womans University Hospital within the framework of the therefore, complex and expensive methods, such as dual-en- “Health check-ups of women”, which was undergone be- ergy X-ray absorption (DXA) or magnetic resonance imag- tween December 2008 and October 2010. The participants ing, must be used to measure body fat accurately.8,9 were recruited from Seoul and the surrounding urban area, Recently, the body adiposity index (BAI) was proposed and they consisted of students (n=1481), office clerks (n= as a tool to evaluate adiposity, to overcome the shortcom- 622), professional workers (n=471), and unemployed wom- ings of BMI.10 BAI can be calculated solely from the hip en including housewives (n=376). Participants in the study circumference and height {(hip circumference)/[(height1.5)- provided complete medical histories regarding their health 18]}, and it can be used to reflect body fat percentage (BF%) status, current medication histories, social habits, such as in adults.10 BAI was suggested to have several advantages alcohol drinking and smoking, eating habits, physical activ- over BMI, including that it yields similar associations with ity, and family histories of chronic disease. Subjects were BF% for men and women and may be more practical to as- excluded from participation if they had any acute disease, sess in field studies because it does not require a weight severe liver, heart, or kidney dysfunction, cancer, or other measurement.11 BAI was developed and validated in studies conditions capable of altering body composition. The use of Mexican-American and African-American adults. Several of certain drugs, such as steroids or diuretics, was also a cri- recent studies of BAI values for predicting fat content or terion for exclusion. The institutional review board of the metabolic disorders in European-American, Mexican- Ewha Womans University Mokdong Hospital approved the American and Caucasian subjects have reported controver- study protocol, and written informed consent was obtained sial results.11-20 In Caucasians, BAI is a better estimate of from all the participants. adiposity than BMI in non-obese subjects, but less effec- tively than BMI in obese men and women.12,15 Another study Methods reported that BMI more strongly correlated with BF% than BAI, and more highly associated with diabetes risk in Cau- Anthropometric examination and body fat analysis casian.14 In Mexican Americans, BAI was correlated more The anthropometric examinations and bioelectrical imped- strongly than BMI with BF% in sex-pooled analyses, but ance tests were performed by a single experienced nurse. not in sex-stratified analyses. Also, BAI is inferior to the The subjects were instructed to avoid all diuretics for 7 widely used BMI as a correlate of the cardiometabolic risk days, alcohol for 2 days, intense exercise for 1 day, and all factors.17 In a Spanish-Mediterranean population, the Re- fluids for 4 hours. ceiver Operating Characteristic (ROC) curve analysis showed Blood pressure was measured using a sphygmomanometer a higher accuracy for BMI than BAI. Also, in African- with standardized oscillometric cuff sizes. Weight and height American and Hispanic women, the use of BAI has no ad- were measured for all the subjects. The waist circumference vantage over the use of BMI.11,16,19,20 Only one study has de- was measured on bare skin at the narrowest indentation be- termined the relationship between both BMI and BAI and tween the 10th rib and the iliac crest at mid-respiration. The BF% in Asian subjects,21 and additionally, the utility of this hip circumference was measured at the widest point over the index for metabolic risk has not yet been confirmed in this greater trochanters. BMI was calculated as the weight in kilo- ethnicity. Therefore, it is important to validate BAI for pre- grams divided by the square of the height in meters (kg/m2), dicting adiposity and metabolic risk in other Asian groups. and BAI was calculated as (hip/height1.5)-188. A BMI of at The objective of this study was to determine whether least 25 kg/m2 is considered obese, based on the Asia-Pacif- Yonsei Med J http://www.eymj.org Volume 55 Number 4 July 2014 1029 Yeon-Ah Sung, et al. ic criteria.22 assay using a commercial kit (Biosource, Nivelles, Bel- After the anthropometric measurements were obtained, gium). Fasting serum total cholesterol, triglycerides, and the subjects were instructed to assume a resting supine po- HDL cholesterol levels were measured with an enzymatic sition for 30 minutes, after which bioelectrical impedance assay on an automated analyzer (Hitachi 7150 Auto-Chem- measurements were taken. A single-frequency bioelectrical istry Analyzer, Tokyo, Japan). impedance plethysmograph was used (InBody 230, Bio- space Industry, Seoul, Korea). Standard electrocardiograph- Statistical analysis ic electrodes were placed on the hands and feet. Isopropyl Statistical evaluation was performed with the SPSS software alcohol was used to clean each electrode attachment site. package, version 18.0 for Windows (IBM Corporation, Chi- The subject’s legs were parted, and the arms were adducted cago, IL, USA). The quantitative variables are provided as by approximately 30° to prevent skin-to-skin contact. The the means±standard deviations. Two-tailed p values <0.05 cut-off used to define obesity was ≥35% BF, which is the were considered significant. Pearson’s correlations were most frequently used value reported in the literature.23-26 used to examine the correlations between BMI and BAI and metabolic indices.15,17,19,21,30 Partial correlation was also Laboratory evaluation used to adjust for the effect of age.