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Cosmic Rays Sound Scary, But Radiation Risk On A Flight Is Small

Sat, 09/06/2014 - 5:30am
Cosmic Rays Sound Scary, But Radiation Risk On A Flight Is Small September 06, 2014 5:30 AM ET

Credit: Katherine Streeter for NPR

If you take a Geiger counter with you on your next flight, you'll notice the dial ratchet up as the plane approaches cruising altitude. Every time you fly, you get zapped by a little extra radiation from space. It goes right through you, in teensy amounts. It's usually nothing to worry about, even if you're pregnant.

But for people who fly a lot — like the plane's crew — that sort of exposure might, in rare instances, amount to something.

Research published Wednesday in JAMA Dermatology shows that pilots and other air crew members have "approximately twice the incidence of melanoma compared to the general population." The study's authors say that difference might be partially due to in-flight exposure to UV and cosmic radiation.

The National Institute for Occupational Safety and Health is using computer models to look into how working as a flight attendant might affect reproductive health. A recent study in the journal Aviation, Space, and Environmental Medicine looked at data from 2 million flights and found that some flight attendants may exceed recommended radiation limits.

The sun regularly shoots charged particles at the Earth, especially during solar temperature tantrums. Earth's atmosphere and magnetic field deflect most of these particles before they reach us.


"This would be uncommon, but it does happen," says Barbara Grajewski, an epidemiologist with NIOSH and an author of the study. "It could be at a level that could be of concern, and in excess of the national recommended dose for a pregnant woman."

In some countries, including the United States, members of a flight crew are considered "radiation workers." According to NASA researchers, a pilot who routinely works long-haul flights may be exposed to about twice the radiation of the average landlubber and more than a fuel-cycle worker in a nuclear power plant.

"Galactic cosmic rays" may sound like beams from an alien weapon, but they're actually the charged particles emitted by stars, including our sun. In an instrument called a cloud chamber, they look like gentle wisps. When accompanied by violinists, they sound like buzzing flies.

The rays pass through us all, "whizzing through you every day of your life," delivering a smidgen of radiation, says radiation physicist Robert Barish, who wrote a book about in-flight radiation. On a long-haul flight, particularly at high latitudes, that smidgen can become a dollop.

There are a few reasons for that. At a passenger jet's cruising altitude — 30,000 feet or more above the ground — the protective layer of atmosphere that surrounds the Earth and deflects cosmic rays isn't as dense. The Earth's magnetic shielding is also weaker over the poles, which means that more radiation enters at high latitudes. And the sun sometimes lets loose with space weather, delivering 100 times more radiation than usual.

Data from the National Council on Radiation Protection and Measurements show the average annual effective dose for workers in various fields. Aviation doses are estimated based on flight routes and altitudes.

NCRP Report 160

Airlines in European Union countries train and monitor their employees as if they were working directly with radioactive materials. Elsewhere, Canada and Japan have issued similar recommendations. U.S. airlines tend to be less prescriptive, though the Federal Aviation Administration has published guidelines to advise them.

The possible health ramifications for flight crews are still under study. NASA is developing a space weather monitoring system that might be used to give airlines a heads up when rays are likely to be particularly intense. The International Commission on Radiological Protection is working on a report on the subject. And an upcoming NIOSH study will look at the possible impact of flight on the risk of miscarriage.

Evidence that solar radiation has any effect on fetuses is scanty, researchers say. "The science says that the fetus is particularly sensitive between the eighth and 15th week," says Jacques Lochard, leader on the upcoming ICRP report. "This is the sensitive period [for] IQ loss."

But most of that information is based on cases of extreme exposure, he says, such as the children of atomic bomb survivors, who would have received a different kind of radiation, and in doses much higher than those experienced on a plane flight.

Radiation is only one part of why European airlines encourage female staff to declare their pregnancy as soon as possible. Jet lag, for example, which entails a disruption of circadian rhythms, might also affect reproductive health.

Even if the risk from occupational exposure to cosmic radiation is small, airlines should routinely provide information that would enable flight crew members to figure out their lifetime exposure, as "a matter of respect," Lochard says.

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Judith Murawski, an industrial hygienist with the Association of Flight Attendants, agrees. "Would it be justified to not mention to nuclear workers that they're being exposed to radiation?" she asks. "It's the same."

There isn't much crews or passengers can do about their exposure, short of avoiding polar flights, or taking a boat instead. Flying airlines at low altitudes would burn more fuel, and it wouldn't make sense to encase jets in heavy protective material.

NIOSH's Grajewski and her co-authors suggest that commercial airlines heed warnings about unusual space weather so they can change flight paths. They also recommend that pregnant members of any air crew choose flight routes that travel at lower altitude and latitude, if they can.

Anyone can estimate their own exposure with various online calculators, or check out space weather conditions, as Murawski did when she was pregnant. "Had there been a solar storm of S2 or higher, then I would not have flown," she says.

Of course, many travelers don't have that level of flexibility or concern. At the end of the day, Grajewski says, it's about probability. "The more you're exposed, the higher the probability" that you've somewhat increased your risk of something like cancer or prenatal defects.

That may sound scary. But this chart, from the blog Information is Beautiful, helps put things in perspective. As the diagram makes clear, walking through an airport security scanner exposes a person to about the same ionizing radiation dose as eating a banana. Flying from New York to Los Angeles exposes you to roughly the same amount of radiation you'd get from eight dental X-rays — and less than you'd get living in a stone house for a year. And those peanuts that airlines hand out? They're a little radioactive, too.

"Radiation is one example of where people have such a wrong idea about what is dangerous, and are also unaware of its ubiquitous nature," says Barish. "Radiation is all around us. It is in us."

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Feds Hope Hitting Nursing Homes In The Wallet Will Cut Overmedication

Fri, 09/05/2014 - 5:45pm
Feds Hope Hitting Nursing Homes In The Wallet Will Cut Overmedication September 05, 2014 5:45 PM ET Listen to the Story 3 min 34 sec  

Federal prosecutors allege two nursing homes in California have "persistently and severely overmedicated elderly and vulnerable residents." Antipsychotic drugs like risperidone, also known as Risperdal, can be dangerous for elderly people, but are frequently prescribed to nursing home patients.

JB Reed/Bloomberg via Getty Images

A federal lawsuit against two Watsonville, Calif., nursing homes may offer a new approach to dealing with the persistent problem of such facilities overmedicating their residents.

The lawsuit details multiple cases when the government says these drugs were inappropriately administered to patients.

For instance when an 86-year-old man identified in the lawsuit as Patient 1 was admitted to Country Villa Watsonville West, he could speak clearly and walked in under his own power. Within days the facility began giving him Haldol and Risperdal, drugs used to treat schizophrenia and bipolar disorder, and he became bedridden, stopped eating and developed bedsores and infections.

"Within days he declined precipitously, to the point where he was read his last rites in the hospital," says Tony Chicotel, a staff attorney with California Advocates for Nursing Home Reform who represented the man and his family in a private suit that was settled out of court.

"He subsequently recovered," says Chicotel, "but all this had been done without his family's knowledge, without his informed consent, without real good clinical indications for the use of the drug."

Antipsychotics like Risperdal and Haldol come with so-called black box warnings that say they could hasten death in elderly patients or people with dementia. Nevertheless, about a fifth of nursing home patients nationwide are prescribed antipsychotic drugs.

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The U.S. attorney for Northern California declined to comment on the lawsuit, but it claims that the two nursing homes provided "grossly inadequate, materially substandard and/or worthless services." Meanwhile, they received about $20 million from Medicare and Medicaid for those services. So now the government wants its money back, and then some.

"Under the False Claims Act, the government can ask for triple damages," explains Kelly Bagby, a senior attorney with the AARP Foundation. The nursing homes also could be fined, she says, for each incidence of filing a false report.

"So every time they submitted a form that said, 'Here is Mrs. Jones' needs' and Mrs. Jones' needs were different than that, each one of those forms is a violation," says Bagby.

In a statement, the companies that own the two nursing homes called the charges "untrue and without merit." They also filed their own lawsuit blaming the company they hired to manage the two facilities.

Deborah Pacyna, public affairs director for the California Association of Health Facilities, says that in the past couple years the federal government, in partnership with organizations like hers, has succeeded in reducing the use of antipsychotic drugs in nursing homes.

"But a lot of the regulators, a lot of our critics seem to be ignoring the fact that antipsychotics are being widely prescribed to patients who have dementia who are living at home, who are in the hospital or who are in assisted living settings," Pacyna says. "Skilled nursing (homes) represents a fraction of those that have been impacted by this practice, yet we remain the focus."

Bagby would like to maintain that focus, and thinks this lawsuit can help do that. "If you're going to hit their bottom line, that's really where you change behavior."

Bagby adds that with antipsychotic drugs still so widely prescribed for nursing home residents, there's the potential for more cases like this one across the country.

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Stinky T-Shirt? Bacteria Love Polyester In A Special Way

Fri, 09/05/2014 - 4:23pm
Stinky T-Shirt? Bacteria Love Polyester In A Special Way September 05, 2014 4:23 PM ET

The bacteria that stink up polyester shirts are different from the bacteria that stink up armpits.

Getty Images/Stock4B Creative

Sure, exercising can make you stronger, happier and healthier. But it can also make you stink. And that polyester workout wear isn't helping.

Anyone with a drawerful of T-shirts knows that the synthetic ones can get sour after just a brief jog, while old-school cotton T-shirts remain relatively stink-free all day. And now science explains why.

The bacteria that flourish on a sweaty polyester T-shirt are different from those that grow on cotton, researchers at the University of Ghent in Belgium found.

Polyester makes a happy home for Micrococcus bacteria, while Staphylococcus, a common armpit denizen, was found on both poly and cotton.

Polyester workout wear is light, comfortable and dries quickly. But it's notorious for getting rank and staying that way. Internet message boards are awash with advice on how to de-stink gym clothes, but the perennial nature of the questions suggests that none of the answers — vinegar, baking soda, avoiding fabric softeners, rinsing your clothes in the shower — works 100 percent of the time.

Microbes love the cozy warmth of the human armpit; it's like a trip to the tropics without ever having to leave home. And it's crowded in there. Those microbes eat compounds in sweat and generate odors, which support a flourishing deodorant industry. One of the authors of this study, Chris Callewaert, is trying to figure out the causes of smelly pits, a quest he details on his website, Dr. Armpit.

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The scientists asked 26 volunteers to take a spinning class while wearing shirts made of cotton, poly or blends. The shirts were then incubated for a day, and the microbes extracted and DNA fingerprinted. Volunteers also had their armpits swabbed. The study was published in the journal Applied and Environmental Microbiology.

It turns out the bugs on the shirts are different from the bugs in the pits. While Corynebacterium is thought to be the main cause of armpit body odor, there was no Corynebacterium on the clothes. Instead, Staphylococcus flourished on cotton and poly, and Micrococcus, bacteria also known for making malodor, loved polyester.

It's unclear how Micrococcus gets on polyester clothing when it's not a dominant species in the armpits, Callewaert says. He's wondering if the bacteria might spread in the washing machine and is doing research to figure that out.

He's also trying to help people with excessive body odor by giving them armpit bacteria transplants. "We have done transplants with about 15 people, and most of them have been successful," Callewaert, a Ph.D. student in applied biological sciences at the University of Ghent, tells Shots. "All have had an effect short term, but the bad odor comes back after a few months for some people."

Manufacturers have tried to make polyester fabric less hospitable to bacteria by impregnating it with antimicrobials like silver nanoparticles or triclosan. Both products have been criticized as having potentially negative impacts on the environment, and there are few data on how they might affect the wearer.

Callewaert thinks the ultimate solution will be something more organic — supplant bad bugs with good ones. "The bacteria has to do a war on its own," he says. "If you have the good bacteria present, eventually you have no bad odor."

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Science On Diets Is Low In Essential Information

Fri, 09/05/2014 - 9:44am
Science On Diets Is Low In Essential Information September 05, 2014 9:44 AM ET

Americans crave information about diets, even as our national weight keeps rising. New studies are highlighting that there is still a lot that we don't know.

A study published Monday in the Annals of Internal Medicine is contributing to water cooler chatter about the benefits of a low-carbohydrate diet compared with one low in fat. The study was a clinical trial in which scientists randomly assigned participants to a low-carbohydrate diet or a low-fat diet and determined the diet's effect on weight and cardiovascular risk factors. They enrolled 148 middle-aged, obese participants.

People assigned to the low-carbohydrate group were told to maintain a diet of total carbohydrate (minus total fiber) of less than 40 grams a day, which is quite restrictive. For comparison, the recommended daily intake of carbohydrates for someone on a 2,000-calorie diet is 300 grams. A single slice of white bread, for example, has about 35 grams of carbohydrates.

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The other group was instructed to keep calories from total fat below 30 percent of daily intake. The subjects were also told to keep calories from saturated fat below 7 percent.

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The findings produced a win for the low-carbohydrate diet, which resulted in about 7 more pounds of weight loss at one year. Participants in the low-carbohydrate group also had more favorable changes in their blood lipid levels, such as cholesterol.

Meanwhile another study, published in JAMA, the journal of the American Medical Association, surveyed prior studies of popular diets and found that the differences between diets like Atkins, Ornish, Zone and Weight Watchers were quite small and not enough to distinguish one from another.

Perhaps the most amazing thing in all this is that there is such scant scientific information available about the actual effects of diets. That's why the randomized trial involving 148 people became big news this week.

The JAMA survey of studies went back as far as 1966 and found fewer than 50 blinded trials. All told, they included fewer than 8,000 people. The studies were generally small (most had fewer than 100 people), and they typically lasted for only 24 weeks. Finally, these trials weren't able to determine whether a particular diet actually lowered the risk of disease.

Our diets may be exerting powerful effects on our health, but we lack studies that assess health events. We commonly expect this kind of study for drugs and other health care interventions. And yet, dietary recommendations are made all the time, and different diets may have different effects on health risk.

We have mostly built recommendations based on observational studies, the kind that watch what happens to people who eat different diets. But these studies are limited because people who eat different diets often have different lifestyles. Vegans and burger-lovers may vary when it comes to other habits that may also influence health, making it difficult to isolate the effects of the diet.

The diet industry generates billions of dollars annually, but it is built on razor-thin evidence about what is best for any individual. And it is likely that one size doesn't fit all. A diet that is best for one person may not be so for another. Ultimately, our recommendations need to be personalized.

Which diet reduces the risk of heart attacks and cancer? The risk factors alone don't tell you. They provide an indication, but there are many instances where an intervention that decreased cardiovascular risk factors didn't lower the likelihood of heart disease. To determine which diets reduce risk for which people, we need larger studies with longer follow-up.

For many people, it will be enough to know whether a low-carbohydrate diet is better for weight loss. Even then, we need additional confirmatory studies that are larger and more definitive.

But for other people, the issue is health and the desire to lower risk along with weight loss. People will have to wait for the answer to the question about which diet is better for their health: low-carbohydrate or low-fat? Truth is, we need answers about the health effects of all the different types of diets that are being promoted. It's time to do the studies.

Harlan Krumholz is a cardiologist and the Harold H. Hines Jr. Professor of Medicine at Yale University School of Medicine. He directs the Yale-New Haven Hospital Center for Outcomes Research and Evaluation and is a director of the Robert Wood Johnson Clinical Scholars Program at Yale.

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