From the latest study: Back belts don't work

Confusion reigns, but don't throw belts out yet

Yet another major study has suggested back support belts are not effective in preventing back injuries, but one researcher cautions that you should not tell your clients to throw out their back belts just yet.

The study is the latest in a string of research strongly suggesting there is no benefit in using back belts to prevent injury from lifting in the workplace, despite the great popularity of such belts in recent years.

This latest study comes from the Institute for Research in Extramural Medicine in Amsterdam, where doctors studied the use of back belts in the cargo department of an airline in the Netherlands.1 Though there may be some limitations to the study, it follows the pattern of several recent reports suggesting that the belts do not decrease low back injuries in the workplace.

The researchers studied 282 cargo workers for six months, using a back belt that has adjustable elastic side pulls with Velcro fasteners and flexible stays and is kept in place with an anchor belt. The belt has no shoulder straps. It comes in four sizes. The workers were given written and verbal instructions on the use of the belt, and they were instructed to wear the belt at all times during working hours. They also were instructed to tighten the side pulls for more support when performing strenuous work.

The 282 workers were divided into these four groups:

1. receiving education only;

2. receiving back belts and education;

3. receiving back belts only;

4. receiving no intervention.

The lifting instructions were designed to make the workers aware of their movement and posture during work. The workers also practiced lifting techniques and relaxation exercises for the neck, shoulder, and back muscles. The last educational session took place at the workplace when workers were actually loading and unloading cargo, with the instructors giving individual advice on lifting and movement.

One of the first findings of the study may be key to interpreting the rest of the results. Compliance with wearing the back belts at least half the time was only 43%. That figure is very low, since it means that some of the 43% were wearing the belt only half the time.

The primary finding of the study was not encouraging. In the four groups, the use of a back belt produced no statistically significant difference in back pain incidence or in sick leave because of low back pain. However, the belts did seem to aid some workers who already had low back pain, reducing their median number of days per month with low back pain from 6.5 days to 1.2 days.

"Overall, lumbar supports or education did not lead to a reduction in low back pain incidence or sick leave," the researchers conclude. "Based on our results, the use of education or lumbar supports cannot be recommended in the prevention of low back pain in industry."

Previous studies have yielded similar conclusions. On the other hand, some research has suggested that the belts do work as promised, so the debate continues.

The study most highly regarded as proving the effectiveness of belts involved a very large cohort of Home Depot workers who performed strenuous activities.2 In that study, the positive effects were so dramatic that the researchers say they have rarely seen such definitive results from an epidemiological study. The research was completely free of any back belt manufacturer sponsorship or involvement.

The study came from the University of California-Los Angeles School of Public Health, where epidemiologist David L. McArthur, PhD, MPH, and other researchers studied the workplace injury history of 36,000 workers of Home Depot over a six-year period. Low back injuries fell by about one-third after the company imposed a consistent policy on belt use.

The decrease was seen across all lines at Home Depot, but the effect was more pronounced in some subgroups. Workers in the youngest set - those aged 25 or younger - suffered 43.8 low back injuries per million hours without back belts, but only 21.7 injuries per million hours with back belts: a prevention rate of 50.5%. Those aged 25 to 34 had a less pronounced but still substantial benefit, with 26 injuries per million hours without belts and 20.2 injuries per million hours with belts - a prevention rate of 22.3%.

The beneficial effect differed for men and women. For men, the rate of injuries was 35.9 per million hours without belts and 22.9 per million hours with belts - a prevention rate of 36.2%. For women, the rate of injuries was 19.2 per million hours without belts and 14.6 per million hours with belts - a prevention rate of 24%.

(For a more complete summary of the research regarding back belt effectiveness, and the debate among occupational health professionals, see Occupational Health Management, February 1997, pp. 13-16.)

Low compliance rate: Results questionable

The debate over the effectiveness of back belts will not end any time soon, says Timothy R. Dillingham, MD, MS, a physiatrist at Johns Hopkins University in Baltimore, who wrote an editorial in the same issue of the Journal of the American Medical Association.3 He tells Occupational Health Management that providers should be careful not to overreact to the negative conclusions in the latest study.

"I still think lumbar supports can be helpful," he says. "I would not discard them solely based on the JAMA article because there are other articles in the literature that show a benefit."

Dillingham is skeptical of many of the studies showing no benefit from the back belts, saying many of them have methodological flaws such as small sample sizes. He also is especially troubled by the low compliance rate in the study from Amsterdam. With only 43% wearing the belts at least half of the time, Dillingham says it is not possible to conclude that the belts offered no benefit.

"That's like doing a drug study and half the people flush the drug down the toilet," he says. "Then you conclude that there's no benefit from the drug."

Dillingham praises the Home Depot study because the compliance was very high, approaching 100% in some circumstances. Encouraging compliance may be the key to making belts effective in reducing low back injuries, he says. And it's not so hard to encourage compliance.

"At Home Depot, the belts were mandatory and they had walk-through checks," he says. "If your employer tells you that the safety officer is going to walk around and anyone without a belt is going to get a reprimand, you're going to use that belt. When compliance was encouraged and measured as very high, the benefits of a back brace were pretty stunning."

Dillingham notes that he often prescribes back belts for his patients with acute back pain, and he wears one himself when working in his yard at home. He says there is no apparent downside to the braces because studies have shown that they do not weaken the back or stomach. "It's a very inexpensive intervention with no downside, and it quite possibly helps," he says.

Reference

1. van Poppel MNM, Koes BW, van der Ploeg T, et al. Lumbar supports and education for the prevention of low back pain in industry. JAMA 1998; 279:1,789-1,794.

2. Kraus JF, Brown KA, McArthur DL, et al. Reduction of acute low back injuries by use of back supports. Int J Occup Environ Health 1996; 2:1-10.

3. Dillingham TR. Lumbar supports for prevention of low back pain in the workplace. JAMA 1998; 279:1,826-1,827.