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Study: Frequent Hand Washing Appears to Reduce Exposure to Hormone-Disrupting PBDEs
By Brenda Goodman
WebMD Health News
Reviewed by Louise Chang, MD
(June 30, 2011) -- Hand washing at work doesn't just keep germs at bay. A new study shows that office workers who frequently lather up have lower levels of hormone-disrupting flame-retardant chemicals on their hands and in their blood.
The study tested for polybrominated diphenyl ethers (PBDEs) in 31 Boston-area offices and found the chemicals, which are used to keep everything from office chairs to carpeting to computers from catching fire, in every work space tested.
Additionally, researchers swabbed the hands of office workers and took blood samples to check for the presence of PBDEs.
Workers who washed their hands at least four times daily had lower levels of PBDEs on their skin, and their blood levels of some kinds of PBDEs were more than three times lower than workers who washed their hands less frequently.
Studies in animals and people suggest that exposure to PBDEs may affect the thyroid and brain. The chemicals, which have been widely used for decades, have also been linked to developmental delays in children and lowered testosterone levels in men. In one study, women with high PBDE levels had a harder time getting pregnant compared to women exposed to lower levels.
U.S. manufacturers voluntarily stopped using some kinds of PBDEs, called penta-PBDEs, in 2004. But because many of the products they made are still in use, the chemicals, which may be stored in the body for years, are still around. Another class of PBDEs, deca-PBDEs, is set to be phased out by 2013.
"It's still everywhere. It's still in people's homes and in people's offices and probably in people's cars, and even though we stopped making it, we still have this residual problem," says study researcher Thomas F. Webster, DSc, associate professor of environmental health in Boston University's School of Public Health.
One of the office buildings tested in the study was newly constructed, Webster says.
Picking Up PBDEs at Work
PBDEs seem to shed into the environment and are found in high levels in dust, but researchers haven't always understood how they get into the body.
"We were trying to figure out how PBDEs get out of products and into people," says study researcher Deborah Watkins, a doctoral candidate at the Boston University School of Public Health.
For the study, researchers recruited 31 adults who worked at least 20 hours a week in eight different office buildings around Boston.
Most of the study participants were women, and they were on average about 49 years old.
Investigators vacuumed the floors of their offices and checked the collected dust for PBDEs.
They also swabbed the hands of study volunteers at least an hour after the last time they washed their hands. They saved and analyzed those gauze pads for PBDEs.
Blood samples were taken and analyzed for 11 different types of PBDEs.
Study participants also answered a battery of questions about their work and personal habits, including the average number of hours they spent at work each day and how often they generally washed their hands.
Penta-PBDEs, the ones that were discontinued in 2004, were found on the hands of all study volunteers and in all the office dust.
And people whose offices had the highest PBDEs in the dust were also the most likely to have high levels on their hands.
But workers who were frequent hand washers, scrubbing at least four times each day, had blood levels of PBDEs that were about three times lower than people who washed their hands less frequently.
"One of the major results we found here is this very strong association between what we found was on people's hands and what was in their blood," Webster says.
That probably means that people aren't coming into contact with PBDEs by inhaling them.
"The more likely scenario is that you're absorbing it through your skin or you're getting it on your hands and then you're eating it," he says.
"Your desk has dust on it. Your keyboard's got dust on it. Actually everything in your whole office has a thin film of organic material on it," Webster tells WebMD. "And so there's PBDEs in that and then you get it on your hands and you eat a sandwich and you get it in your mouth."
The study was published in Environmental Health Perspectives.
Computers, Electronics Are Common Office Sources
Most previous studies have looked at household levels of PBDEs.
But a study published last year by researchers at the University of Michigan at Ann Arbor looked at 10 commercial and institutional buildings in that state and found levels of the chemicals "at the upper range" of previously reported levels. Levels were especially high in buildings that housed computer servers.
Flame retardants are widely used to insulate electronics, especially products that get hot when they're turned on, like computers.
But strikingly, both studies found the discontinued penta-PBDEs in newly constructed and furnished buildings, and researchers say they can't fully explain why because they didn't try to trace the source of the PBDEs to individual office items.
"Just because stuff isn't manufactured doesn't mean it isn't in use anymore. It could be that people brought in old stuff, old furniture, and old computers," he says.
The good news, Webster says, is that there appears to be a way to cut down on the exposure to flame retardants.
"You can actually wash your hands," he says. "Washing your hands is really great public health advice. It cuts down on infectious disease, and it looks like it may reduce exposure to these kinds of chemicals, too."