Skinny people, too. if you get past the weak statistics, the theory is…
The authors point to other research, showing that the lower body of obese drivers is propelled further forward on impact before the seatbelt engages the pelvis, because of the additional soft tissue which prevents the belt from fitting snugly, while the upper body is held back.
Media release below.
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Obese much more likely to die in car crashes than normal weight drivers
Car design may have to change to better protect them, suggest authors
The findings prompt the researchers to consider whether car design might need to change to afford greater protection to the considerable proportion of obese people in the population – currently around a third of all US adults.
The researchers used data from the US Fatality Analysis Reporting System (FARS) for 1996 to 2008. This is operated by the National Highway Traffic Safety Administration and records all fatalities arising within 30 days of a traffic collision.
During this period, details of 57,491 road traffic collisions were submitted to the system.
The researchers looked for collisions in which two passenger vehicles were involved, and for which the impact of the crash was the most harmful component of the incident, resulting in the deaths of one or both drivers.
They also looked for collisions in which both parties had been driving vehicles of similar size and type. They selected 3,403 pairs of drivers for whom data on weight, age, seat belt use and airbag deployment were available.
Almost half of these drivers (46%) were of normal weight; one in three was overweight; and almost one in five (18%) were obese.
Two thirds were male, and almost one in three was aged between 16 and 24; one in three was not using a seat belt properly – lap or shoulder only, rather than both – and in over half (53%) of cases, the airbag deployed.
The analysis showed that risk of death increased the more obese the driver was, according to the World Health Organization classification, which categorises obesity from levels I to III.
At level I, obese drivers were 21% more likely to die; at level II they were 51% more likely to do so; and at level III they were 80% more likely to do so than drivers of normal weight.
When broken down by gender, obese women were at even greater risk. At level I they were 36% more likely to die; at level II they were more than twice as likely to do so; and at level III they were almost twice as likely to die.
Interestingly underweight men were also more likely to die in a collision than their normal weight peers.
There were no significant differences among different types of vehicle, collision or use of seat belts, although almost a third of drivers who sustained a fatal injury were not properly belted.
The authors point to other research, showing that the lower body of obese drivers is propelled further forward on impact before the seatbelt engages the pelvis, because of the additional soft tissue which prevents the belt from fitting snugly, while the upper body is held back.
They also suggest that obese drivers may be more likely to have underlying health problems, which may contribute to their greater risk of death. But car design may need to change, they venture.
“The ability of passenger vehicles to protect overweight or obese occupants may have increasingly important public health implications, given the continuing obesity epidemic in the USA,” they write. And they add: “It may be the case that passenger vehicles are well designed to protect normal weight vehicle occupants but are deficient in protecting overweight or obese occupants.”
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If the hypothesis relates to movement of the pelvis in high-BMI vs intermediate-BMI vs low-BMI, the next question would be, how does the pelvic movement affect the injuries received.
It’s reasonable to think that people of very different BMI may move differently within the restraint system and that the different movements may cause differing injuries.
My understanding is that most people killed in vehicle accidents die when they either leave the vehicle or collide with something inside the vehicle. It seems doubtful that BMI would affect this directly, although high-BMI individuals may be less compliant in using their seatbelts. Extenders could be a partial answer.
This is an interesting and perhaps valuable area of research. When followed out, it may prove illusory or it may provide answers that can help save lives and ability.
The media is using this story to pile on more anti-obesity hype, suggesting that fat people are inherently more likely to die because they’re unhealthy and should just lose weight [http://www.dailyrx.com/obese-individuals-car-crashes-more-likely-die-those-normal-weight] to avoid dying in a car accident. Instead, they could be offering sounder information and a public health message that might actually help people and save lives.
This latest study isn’t publicly available yet, so the media is reporting the press release. But the study, led by Thomas M. Rice, MPH, PhD, with SafeTREC at the University of California, Berkeley, was presented [https://apha.confex.com/apha/140am/webprogram/Paper269789.html] last October at the American Public Health Association meetings. The authors’ focus was on the automobiles, not on blaming fat people, and found that the risks of dying in an automobile accident were slightly higher for extremely thin adults but almost two-fold higher among those at the highest ranges of body size. Most telling, the risks were much greater for women, who are more likely to carry their weight in their hips and lower body than men.
They pointed out research showing that the seatbelts in passenger vehicles are not designed to fit snuggly over the lower body of the very large people and their bodies are propelled forward on impact before the seatbelts engage the pelvis. They concluded that “passenger vehicle restraint systems as used do not adequately protect obese and very obese drivers during severe traffic collisions.” While seat belt use itself didn’t change the risks, the authors weren’t able to evaluate how many had the appropriately fitting seat belt for their size.
This confirms what research has been showing for over a decade. Just as small children benefit by properly sized seat belts and restraints, so do larger adults. Seat belt manufacturers currently design once-size-fits-all seat belts that aren’t. Throughout the last decade research has been reporting [http://www.ncbi.nlm.nih.gov/pubmed/18301207] and cautioning that fat people are less likely to use appropriately fitted seat belts or to wear seat belts at all [http://usatoday30.usatoday.com/news/health/2008-02-08-obesity-seat-belts_N.htm], including teens [http://www.ncbi.nlm.nih.gov/pubmed/21181247], leading to nearly 10-fold increased risks of dying in auto accidents. This spurred efforts to encourage car manufacturers to offer seat belt extenders for their vehicles for people with larger BMIs, as well as for pregnant women.
The public health message, if media cared about actually trying to help people, is that wearing a proper fitting seat belt could save lives of people of every size. And, if you weigh over 215 pounds, the seat belt that comes with your vehicle may not be right for you. Information on getting a seat belt extender for your vehicle is available from such resources as Seat Belts for Larger Passengers [http://www.ifisher.com/getbelts.asp].