Fat Workers and On-the-Job Injuries, Take 2


As a few commenters pointed out last week, I was insufficiently skeptical of the recent Duke University study that found an association between body-mass index (BMI) and workplace injuries. My biggest mistake was citing the dramatic numbers that were highlighted in the news coverage (and in the JAMA press release), comparing the workers' compensation claims of the most obese employees with those of employees in the "recommended weight" range. These numbers came from a simple analysis that did not control for occupational category. Not surprisingly, certain kinds of jobs, the ones involving a lot of manual labor and heavy lifting, had higher injury rates than others. And as the researchers note, "Employees in several of the high-risk occupations were heavier than average…, emphasizing [the need for] caution in the interpretation of the bivariate relationships."

In the multivariate analysis, which took job category into account, the differences between weight groups were much smaller: The heaviest workers had a claim rate only 45 percent higher than that of the "recommended weight" workers, compared to twice as high in the bivariate analysis. The  rate for the merely "overweight" employees was essentially the same as the rate for their thinner co-workers. The number of lost workdays per claim and the costs per claim were still substantially higher in the heaviest group, but the ratios after adjustment were not as dramatic as the ones I cited. Sandy Szwarc notes the importance of adjusting for job category and mentions some other study limitations here.

It's not clear why heavier employees in the same jobs had higher workers' compensation costs. As I noted in last week's post, there are plausible reasons to think some of the difference may be due to extra weight per se, but fitness might also be a factor. The researchers mention a few other possible explanations:

If obese nurses (because of discrimination or for some other reason) are less likely to get promoted, they may be doing more of the heavy lifting. It is also possible that obese workers, given the same illness or injury, may be more or less likely to submit a workers' compensation claim than a colleague of recommended weight; we cannot assess this possibility based on our data. Furthermore, there are potential underlying unobservable factors that might make obese individuals more likely to get injured independent of their weight. Education may be such a factor, although educational differences are, at least to some extent, adjusted for through occupational category.

In short, the association is not as strong as the press coverage implied, and it does not prove a cause-and-effect relationship—points to keep in mind when anti-fat activists cite this study as evidence that obesity imposes costs on others. In any case, assuming excess weight does contribute to workplace injuries, the appropriate response—whether fitness programs, BMI limits for job candidates, or nothing at all—should be left to employers, who are in the best position to judge the impact on their own bottom lines.

NEXT: So How's That War on Terror Going?

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  1. In short, the association is not as strong as the press coverage implied

    Is it ever?

  2. You do realize BMI was created at around 1830? It is vastly outdated.

    Watch the Penn and Teller episode on Obesity, it talks about a lot of this. Penn Jillette also covered it on his past radio show (R.I.P.)

  3. Keep in mind that having a high BMI doesn’t necessarily mean that someone is obese–muscle weighs more than fat, after all. I don’t think it’s unreasonable to speculate that people in those jobs with heavy lifting and manual labor are likely to be considerably stronger than the average office worker.

  4. “The heaviest workers had a claim rate ONLY 45 percent higher than that of the “recommended weight” workers, compared to twice as high in the bivariate analysis.”

    Maybe I’m too pro-business and not analytical enough, but damn… so it isn’t “twice as much”…. it’s still (almost) “half again as much”. That’s a lot. Loss some weight. Or get taller.


  5. I am fat and I got hurt at work and this is a very offensive thread.

  6. Did it say anything about fat people’s bad engineering skills? I am waiting for Rosie to tell us how the California freeway collapse was an inside job since fire can’t melt steel.

  7. Another thing to take in to account is the fact that most of us gain weight as we age. Some of the injuries and sicknesses can be attributed to the extra weight, but how much is associated with the extra years?

  8. I meant “gain EXTRA weight as we age”. Damn self-editor mode clicked in too late again.

  9. I got fat because of work.

  10. I think Sandy made it quite clear why workers primarily in lower paying positions involving more physical labor would incur slightly higher costs. The fact that they were also slightly heavier is a straw man argument.

  11. I am waiting for Rosie to tell us how the California freeway collapse was an inside job since fire can’t melt steel.

    That is really kind of funny that you mention that, I was just thinking about that. I do agree with Rosie that steel will only melt under certain conditions, perhap though, because of my weight, I can not elucidate explicitly what those are.

  12. If I only had a brain!

  13. I imagine the best way to approach this isn’t to look at total dollars spent, but dollars spent per given injury. Let’s say a type of injury is common among certain workers. How long do they spend hospitalized, and how long are they home from work? This way they aren’t confusing how injury prone fat people are with how poorly they recover from the injury. It’s well established that fat people are prone to more complications from an injury, or surgery for that matter. It’s has to cost something, eh?

  14. their own bottom lines

    = VPLs?

  15. The hormone-releasing pill has so far only been given to female monkeys and shrews who displayed more mating behaviour and ate less.

    That’s not like any shrew I was ever married to.

  16. How about the more common sense scenario, in contrast to the leading assumption of the obese nurse, that if a physicaly fit man falls a few feet from a ladder, he’s more likely to get up and keep working with only a bruise or two. As opposed to the overweight and proportionately less coordinated guy who falls the same distance and is out of work for two weeks on disability pay.

    Not only is the heavier man more likely to fall due to less coordination, the fall itself will be more damaging due to his size, and inability to flex, stretch and react.

    I had a maintenance man literally fall on me from a ladder at my last place of employment. He only hit my head and shoulder, and then hit the floor with a mighty thump.

    Jacked him up royally, but I’ve taken much harder falls than that doing jiu-jitsu, playing ball, etc and just walked away a little sore.

  17. Ray, did he sue you as being the cause of his injuries? You were the last thing he came in contact with before hitting the ground, after all.

    I’m only half joking.

  18. Secretary position opening at mid-size local engineering firm.

    Flexible hours and good pay. FT/PT. Prior office experience required. Microsoft Office skills a plus.

    No Fatties.

  19. “…keep in mind when anti-fat activists cite this study as evidence that obesity imposes costs on others…”

    Even if the study was true, obesity still would not be imposing any costs on others.

    Government health care schemes and forced insurance pooling would be imposing costs on the subjects of those state initiatives.

  20. I think it’s pretty obvious that the better shape you’re in (as in having a respectable anount of muscle mass and not carrying a lot of fat) the less you will be injured in a fall or while lifting boxes, etc.

    My BMI says I’m fat- I work out so I weigh a lot for my height. I don’t injure easily either. Fall off my bike at speed, maybe a bruise, slip on ice- land on my back, I’m able to keep my head for hitting the ground, etc.

  21. “Even if the study was true, obesity still would not be imposing any costs on others”

    Yep, having by bus trip time increased by 10% because numerous “heavy” people can barely make it up the stairs costs me nothing. Oh and I love unrestrained soft shoulders and thighs that I share my seat with on the plane.

  22. If fatty is 45% more likely to file a claim, for any correlated reason, isn’t that a good reason not to hire him?

    I always chuckle at the protestations: Athletes have high BMIs!

    Right, that’s our biggest health problem. Too much muscle.

  23. the California freeway collapse was an inside job since fire can’t melt steel

    The driver of the gasoline tanker had a criminal record too. And he may be an illegal.
    That sound you hear is Bill O’Reilly’s posse getting all up in that guy’s shit.

    Oh, and fat can melt steel too. Toss a match on Rosie and step back.

  24. Then again, perhaps that tendency is offset by us fatties generally staying at our desks more? “No, I can’t help move those boxes. In the interest of our company’s worker’s comp fund, I’m staying at my desk at eating another ho-ho.”

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