BMI and Risk of Serious Upper Body Injury Following Motor Vehicle Crashes: Concordance of Real-World and Computer-Simulated Observations Shankuan Zhu 1,2 *, Jong-Eun Kim 3 , Xiaoguang Ma 1 , Alan Shih 3 , Purushottam W. Laud 4 , Frank Pintar 1,5 , Wei Shen 6 , Steven B. Heymsfield 7 , David B. Allison 8 1 Injury Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America, 2 Injury Control Research Center, and Obesity and Body Composition Research Center, Zhejiang University School of Public Health, Hangzhou, China, 3 Department of Mechanical Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America, 4 Department of Population Health, Division of Biostatistics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America, 5 Neurosurgery Neuroscience Lab, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America, 6 Obesity Research Center, St. Luke’s Roosevelt Hospital and Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, New York, United States of America, 7 Center for Scientific Affairs, Merck & Co., Rahway, New Jersey, United States of America, 8 Department of Biostatistics, and Nutrition and Obesity Research Center, University of Alabama at Birmingham, Alabama, United States of America Abstract Background: Men tend to have more upper body mass and fat than women, a physical characteristic that may predispose them to severe motor vehicle crash (MVC) injuries, particularly in certain body regions. This study examined MVC-related regional body injury and its association with the presence of driver obesity using both real-world data and computer crash simulation. Methods and Findings: Real-world data were from the 2001 to 2005 National Automotive Sampling System Crashworthiness Data System. A total of 10,941 drivers who were aged 18 years or older involved in frontal collision crashes were eligible for the study. Sex-specific logistic regression models were developed to analyze the associations between MVC injury and the presence of driver obesity. In order to confirm the findings from real-world data, computer models of obese subjects were constructed and crash simulations were performed. According to real-world data, obese men had a substantially higher risk of injury, especially serious injury, to the upper body regions including head, face, thorax, and spine than normal weight men (all p,0.05). A U-shaped relation was found between body mass index (BMI) and serious injury in the abdominal region for both men and women (p,0.05 for both BMI and BMI 2 ). In the high-BMI range, men were more likely to be seriously injured than were women for all body regions except the extremities and abdominal region (all p,0.05 for interaction between BMI and sex). The findings from the computer simulation were generally consistent with the real-world results in the present study. Conclusions: Obese men endured a much higher risk of injury to upper body regions during MVCs. This higher risk may be attributed to differences in body shape, fat distribution, and center of gravity between obese and normal-weight subjects, and between men and women. Please see later in the article for the Editors’ Summary. Citation: Zhu S, Kim J-E, Ma X, Shih A, Laud PW, et al. (2010) BMI and Risk of Serious Upper Body Injury Following Motor Vehicle Crashes: Concordance of Real- World and Computer-Simulated Observations. PLoS Med 7(3): e1000250. doi:10.1371/journal.pmed.1000250 Academic Editor: Emmanuel Lagarde, Research Center INSERM U897 ‘‘Epide ´ miologie et Biostatistiques’’, France Received January 29, 2009; Accepted February 17, 2010; Published March 30, 2010 Copyright: ß 2010 Zhu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was supported by a grant from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health (grant R01EB006552-01A1, Obesity-Related Variables and Motor Vehicle Injury). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Abbreviations: AIS, abbreviated injury scale; BMI, body mass index; CI, confidence interval; CDS, crashworthiness data system; MADYMO, mathematical dynamic models; MVC, motor vehicle crash; NASS, national automotive sampling system; OR, odds ratio; PMHS, postmortem human surrogates; SES, socioeconomic status * E-mail: szhu@mcw.edu PLoS Medicine | www.plosmedicine.org 1 March 2010 | Volume 7 | Issue 3 | e1000250