Effects of BMI on the risk and frequency of AIS 3+ injuries in motor‐vehicle crashes

Rupp, Jonathan D.; Flannagan, Carol A. C.; Leslie, Andrew; Hoff, Carrie N.; Reed, Matthew P.; Cunningham, Rebecca M.

doi:10.1002/oby.20079

Cited by 52 publications

(31 citation statements)

References 28 publications

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“…Using computational modeling, Stemper and colleagues 89 demonstrated greater facet joint capsular ligament distortions (up to 73%) for straight and kyphotic cervical spine curvatures (FIGURE 7), indicating remarkably increased injury risk. These findings showed that pre-existing abnormal curvatures inherently altered mechanisms of load transfer in the cer- 74 but has not been investigated for rear impacts using experimental or epidemiological methods. However, increased BMI is likely associated with greater neck muscle mass and greater torso mass, which can reduce injury risk during rear impacts through the mechanisms described above, as can decreased neck slenderness and greater energy absorption of the seatback.…”

Section: Cervical Spinal Posturementioning

confidence: 99%

Whiplash-Associated Disorders: Occupant Kinematics and Neck Morphology

Stemper¹,

Corner²

2016

J Orthop Sports Phys Ther

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FIGURE 1.Initial phases of head-neck response to automotive rear impacts. The rear impact initiates with the occupant in a neutral upright position. As the thorax is accelerated anteriorly, the head remains stationary during the retraction phase, producing an S-shaped cervical spine curvature. Eventually, loads from the thorax are transferred up the cervical spine and the head-neck complex transitions into extension, with the cervical spine in an overall C-shaped extension curvature. The head eventually rebounds forward (not shown), and the cervical spine then transitions into flexion. Used with permission from Stemper et al. 93 Copyright ©2011 Wiley-Liss, Inc. foam/springs and rearward deflection, which absorb energy and decrease impact severity for the occupant. The magnitude of seatback deformation and deflection is dependent on the occupant's torso mass and center of gravity. Greater mass and higher center of gravity contribute to greater deflection and decreased overall impact severity. Average female body mass is 20% lighter and torso height is 8% shorter. 30,31 Therefore, the ability to deflect the seatback is decreased in females, who would experience more severe loading on the head-neck complex during a given rear impact.This section highlighted the role of body size on cervical spine injury risk during automotive rear impacts, advancing the theory that size-based mismatches between the vehicle seat and occupant anthropometrics contribute to greater injury risk for smaller occupants. This concept would hold true for either males or females, but may help explain the preponderance of whiplash injuries in females due to their generally smaller body size. Shorter sitting height can result in head interaction with the bottom of the head restraint, which increases injury risk. However, taller occupants with incorrectly adjusted head restraints also experience increased injury risk due to the head rotating over the head restraint and increasing extension moments on the cervical spine. Decreased body mass and shorter center-of-torso mass in smaller occupants also contribute to decreased dynamic energy absorption of the seatback. While these differences illustrate mechanisms of increased injury risk for smaller occupants, other morphological differences may also contribute. Differences in Head and Neck MorphologyGiven that a majority of injuries resulting from automotive rear impacts affect the cervical spine, 9 differences in headneck morphology can influence injury risk. Once again, sex-based differences will be used to demonstrate this concept. Neck slenderness, a mechanical term body sizes farther from those standards may not be protected as well.Research studies report that head-tohead restraint backset is lower in females than in males due to rearward incline of automotive seats and decreased sitting height for average females compared to males.12 Sitting height for average females is approximately 6 cm shorter than that for average males. 30,31 This means that the posterior aspect of the head for the comp...

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Section: Cervical Spinal Posturementioning

confidence: 99%

Whiplash-Associated Disorders: Occupant Kinematics and Neck Morphology

Stemper¹,

Corner²

2016

J Orthop Sports Phys Ther

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“…(Augenstein, Perdeck et al 2003, Austin and Faigin 2003, Newgard 2008, Insurance Institute on Highway Safety 2010, Ridella, Rupp et al 2012) Obesity also increases the risk of death and serious injury, although males and females may be affected differently. (Choban, Weireter et al 1991, Boulanger, Milzman et al 1992, Mock, Grossman et al 2002, Arbabi, Wahl et al 2003, Neville, Brown et al 2004, Zhu, Layde et al 2006, Ryb and Dischinger 2008, Viano, Parenteau et al 2008, Sivak, Schoettle et al 2010, Jehle, Gemme et al 2012, Rupp, Flannagan et al 2013) Some studies find an increased risk only for male obese drivers,(Zhu, Kim et al 2010, Ma, Laud et al 2011) while others find an increased risk for both obese male and female drivers, although greater for obese males. (Viano, Parenteau et al 2008) On average, male drivers experience more severe crashes than female drivers (Insurance Institute on Highway Safety 2010), but prior research has also shown that in crashes of equal severity, women are more likely than men to be injured or killed.…”

Section: Introductionmentioning

confidence: 99%

“…Kent et al (2009) used information on the distribution of occupants involved in crashes by age and the risk of injury as a function of age normalized to the risk of a twenty year old to characterize the effects of age on the number of occupants killed and injured in crashes. Rupp et al (2013) modeled the risk of serious-to-fatal injury to different body regions in frontal, nearside, farside, and rollover crashes as functions of significant predictors of injury and then applied these models to a probability sample of occupants in crashes, adjusting the BMI distribution in this sample to estimate the effect of BMI in terms of the numbers of occupants with injury to different body regions in different crash modes.…”

Section: Introductionmentioning

confidence: 99%

Comparing the effects of age, BMI and gender on severe injury (AIS 3+) in motor-vehicle crashes

Carter

Flannagan

Reed

et al. 2014

Accident Analysis & Prevention

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Background The effects of age, body mass index (BMI) and gender on motor vehicle crash (MVC) injuries are not well understood and current prevention efforts do not effectively address variability in occupant characteristics. Objectives 1) Characterize the effects of age, BMI and gender on serious-to-fatal MVC injury 2) Identify the crash modes and body regions where the effects of occupant characteristics onthe numbers of occupants with injuryis largest, and thereby aid in prioritizing the need forhuman surrogates that the represent different types of occupant characteristics and adaptive restraint systems that consider these characteristics. Methods Multivariate logistic regression was used to model the effects of occupant characteristics (age, BMI, gender), vehicle and crash characteristics on serious-to-fatal injuries (AIS 3+) by body region and crash mode using the 2000-2010 National Automotive Sampling System (NASS-CDS) dataset. Logistic regression models were applied to weighted crash data to estimate the change in the number of annual injured occupants with AIS 3+ injury that would occur if occupant characteristics were limited to their 5th percentiles (age ≤ 17 years old, BMI ≤ 19 kg/m2) or male gender. Results Limiting age was associated with a decrease inthe total number of occupants with head [8,396, 95% CI 6,871-9,070] and thorax injuries [17,961, 95% CI 15,960 – 18,859] across all crash modes, decreased occupants with spine [3,843, 95% CI 3,065 – 4,242] and upper extremity [3,578, 95% CI 1,402 – 4,439] injuries in frontal and rollover crashes and decreased abdominal [1,368, 95% CI 1,062 – 1,417] and lower extremity [4,584, 95% CI 4,012 – 4,995] injuries in frontal impacts. The age effect was modulated by gender with older females morelikely to have thorax and upper extremity injuries than older males. Limiting BMI was associated with 2,069 [95% CI 1,107 – 2,775] fewer thorax injuries in nearside crashes, and 5,304 [95% CI 4,279 – 5,688] fewer lower extremity injuries in frontal crashes. Setting gender to male resulted in fewer occupants with head injuries in farside crashes [1,999, 95% CI 844 – 2,685] and fewer thorax [5,618, 95% CI 4,212 – 6,272], upper [3,804, 95% CI 1,781 – 4,803] and lower extremity [2,791, 95% CI 2,216 – 3,256] injuries in frontal crashes. Results indicate that age provides the greater relative contribution to injury when compared to gender and BMI, especially for thorax and head injuries. Conclusions Restraint systems that account for the differential injury risks associated with age, BMI and gender could have a meaningful effect on injury in motor-vehicle crashes. Computational models of humans that represent older, high BMI, and female occupants are needed for use in simulations of particular types of crashes to develop these restraint systems.

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“…28 Rupp et al reported head-on MVCs to be associated with higher risk for lower and upper extremity injuries, as well as spinal injuries in obese patients. 29 Obesity is associated with increased anterior abdominal fat content and as such, could serve as a protective factor for abdominal blunt and penetrating injuries. Bloom et al evaluated chest and abdomen abbreviated injury scale (AIS).…”

Section: The Effect Of Bmi In Injury Patterns and Recovery Timementioning

confidence: 99%