Accuracy of Current Body Mass Index Obesity Classification... : Obstetrics & Gynecology (original) (raw)
Original Research
Accuracy of Current Body Mass Index Obesity Classification for White, Black, and Hispanic Reproductive-Age Women
From the Department of Obstetrics and Gynecology and the Center for Interdisciplinary Research in Women's Health, Galveston, Texas.
Supported by two grants awarded by the Eunice Kennedy Shriver National Institute of Child Health & Human Development to A.B.B.: Research grant (R01HD039883) and, a Midcareer Investigator Award In Patient-Oriented Research Award (K24HD043659). Additional support provided by the General Clinical Research Centers program (M01RR00073), National Center for Research Resources, National Institutes of Health.
The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Child Health & Human Development or the National Institutes of Health.
Corresponding author: Mahbubur Rahman, MD, PhD, MPH, Center for Interdisciplinary Research in Women's Health, Department of Obstetrics & Gynecology, University of Texas Medical Branch, Galveston TX 77555-0587; e-mail: [email protected].
Financial Disclosure The authors did not report any potential conflicts of interest.
OBJECTIVE:
To compare the National Institutes of Health's (NIH) body mass index (BMI)-based classification to identify obesity in comparison with the World Health Organization (WHO), which uses percent body fat, among white, black, and Hispanic reproductive-aged women.
METHODS:
Body weight, height, BMI, and percent body fat (dual-energy X-ray absorptiometry generated) were determined for 555 healthy adult women aged 20–33 years (mean±standard deviation 26.5±4.0 years). Diagnostic accuracy of the NIH-based obesity definition (BMI of 30 kg/m2 or higher) was determined using the WHO criterion standard (percent body fat greater than 35%).
RESULTS:
Obesity as defined by the NIH (BMI 30 kg/m2 or higher) and by WHO (percent body fat greater than 35%) classified 205 (36.9%) and 350 (63.1%) of the women as obese, respectively. The NIH-defined obesity cutoff values had 47.8%, 75.0%, and 53.9% sensitivity in white, black and Hispanic, women, respectively. White and Hispanic women had 2.9% greater percent body fat than black women for a given BMI. Receiver operating characteristics curves analyses showed that the respective sensitivities improved to 85.6%, 81.3%, and 83.2%, and that 311 women (56.0%) were classified as obese as a whole when race or ethnic-specific BMI cutoff values driven by our data (BMI at or above 25.5, 28.7, and 26.2 kg/m2 for white, black, and Hispanic women, respectively) were used to detect percent body fat–defined obesity.
CONCLUSION:
Current BMI cutoff values recommended by the NIH failed to identify nearly half of reproductive-aged women who met the criteria for obesity by percent body fat. Using race or ethnic-specific BMI cutoff values would more accurately identify obesity in this population than the existing classification system.
LEVEL OF EVIDENCE:
II
© 2010 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.