A recent study from the Mayo Clinic showed that obese people are 25 percent more likely than people with a healthy weight to develop rheumatoid arthritis (RA), an autommune disease that causes painful joint inflammation and damage to surrounding tissues. In a Shots blog post today, Gretchen Cuda-Kroen takes a closer look at the findings:

…Although it may seem intuitive that excess body weight could cause joint pain, says Eric Matteson, [MD,] a rheumatologist at the Mayo Clinic who led the study, the link between rheumatoid arthritis and obesity is more than just stress on the joints from being heavy.

“The link, we think, has to do with the activity of the fat cells themselves,” says Matteson.

Unlike osteoarthritis, a form of arthritis that is caused by wear and tear on the joints, rheumatoid arthritis is an autoimmune disease, says Matteson. It occurs when the body’s immune system attacks the lining around joints, and the resulting inflammation leads to the destruction of bone and cartilage. Matteson says it’s the fat cells that stoke the fire of inflammation.

“We have recognized in the past several years that fat cells are important mediators of inflammation,” Matteson says. “They are immunologically active, and they produce proteins that are inflammatory.”

Matteson goes on to say that weight loss may be helpful for patients with RA. Besides helping to relieve joint strain, he says, “losing weight also generally makes the drugs work better.”

Previously: Can yoga help women suffering from rheumatoid arthritis?, A “promising time” for lupus research and Lupus and rheumatoid arthritis may mean fewer children for female patients

What could your browsing behavior reveal about your mental health? Recent research from Missouri University of Science and Technology observed, with permission, the Internet-using habits of 216 undergraduates to study whether certain patterns were associated with depressive symptoms in the students.

The researchers measured the participants’ levels of depression at the start of the study. From a Healthland piece:

About 30% had some depressive symptoms like low mood, loss of concentration and excessive feelings of anxiety. This doesn’t mean that a third of college students were clinically depressed; rather, they had at least some of the symptoms associated with the disorder. The finding is in line with data from surveys showing that 10% to 40% of college students have depressive symptoms at one time or another.

Study authors Sriram Chellappan, PhD, and Raghavendra Kotikalapudi, MS, write in a New York Times article that their research didn’t involve eavesdropping on personal information in e-mails or conversations, but rather looked broadly at traffic flow and other indicators of how the students used the Web. Chellappan and Kotikalapudi commented on their two major findings, saying:

First, we identified several features of Internet usage that correlated with depression. In other words, we found a trend: in general, the more a participant’s score on the survey indicated depression, the more his or her Internet usage included these (rather technical-sounding) features — for instance, “p2p packets,” which indicate high levels of sharing files (like movies and music).

Our second major discovery was that there were patterns of Internet usage that were statistically high among participants with depressive symptoms compared with those without symptoms. That is, we found indicators: styles of Internet behavior that were signs of depressive people. For example, participants with depressive symptoms tended to engage in very high e-mail usage. This perhaps was to be expected: research by the psychologists Janet Morahan-Martin [PhD] and Phyllis Schumacher [PhD] has shown that frequent checking of e-mail may relate to high levels of anxiety, which itself correlates with depressive symptoms.

The investigators also found that Internet usage of depressive people could include frequent switching among applications and increased consumption of videos and playing of games.

Previously: Recognizing mental health problems through Facebook and Analyzing H1N1 vaccination rates and attitudes using Twitter data
Photo by Unhindered by Talent

Walking near Washington Square Park when I used to live in San Francisco’s North Beach neighborhood, I loved to watch the dozens of Chinese seniors that would gather to perform fluid tai chi exercises in near unison. Their ease of movement as well as the dedication, steady focus and sociability they brought to their practice amazed me.

I thought of their meditative motions while reading a recent Atlantic article on a study from the University of South Florida (USF) and Fudan University in Shanghai, China showing that practicing tai chi may enlarge the brain and boost memory.

In the study, published in the Journal of Alzheimer’s Disease, a controlled trial of 120 non-demented seniors from Shanghai were randomized to four groups. Each of three groups practiced tai chi, walking, or social interaction, while the fourth group received no intervention. Cognitive abilities were assessed by MRI and neuropsychological measures for dementia and certain mental capacities.

From The Atlantic:

The subjects in the control group showed brain shrinkage that was consistent with what has generally been observed among people in their 60s and 70s. The participants who practiced tai chi thrice a week, however, showed significant increases in brain volume as well as improvements in their memory and thinking test scores.

Previous research has been conducted on aerobic physical activity’s effect on the aging brain, and a Stanford study examined the less-aerobic tai chi’s ability to combat memory loss in older adults.

Previously: Study examines the benefits of Tai Chi for the elderly
Photo by MargiL

PLoS Medicine has launched a three-week series examining “Big Food,” the major food and beverage companies that influence consumption behavior globally, and this industry’s role in health.

An editorial details the nature of the series:

The PLoS Medicine series on Big Food is a “sampler,” offering perspectives on select topics relevant to how the food industry operates in health. In this first week the guest editors lay out a background and three competing views of how public health professionals can respond….In subsequent weeks we will publish analyses of the rapid rise of Big Food sales in developing countries, an essay on food sovereignty and who holds power over food, and two perspectives from South America and Africa on the displacement of traditional diets by the incursion of multinational food companies.

In an essay kicking off the series, guest editors David Stuckler, MPH, PhD, and Marion Nestle, MPH, PhD, emphasize the complexity of the global food system and the problematic concurrence of obesity and starvation that has resulted. Illustrating the difficulty of reforming practices surrounding the consumption and distribution of food, which is necessary to survival, as opposed to tobacco or alcohol, which are not, Stuckler and Nestle point to what can be learned from the operations of Big Tobacco and argue for possible solutions for the slipperier problem of food and beverage.

Previously: What’s being done about the way tobacco companies market and manufacture products, Better school lunches – in China and A call for understandable information on food labels
Via Boostershots

A Stanford study published last month found that 3.6 percent of U.S. adults sleepwalk. That means that more than 8.4 million Americans could be wandering in the night unconscious of their actions. Some, like my brother who once woke up in the kitchen after chewing through a PowerBar wrapper, exhibit harmless behavior. But others may attempt to drive a car or engage in far more dangerous activities.

As reported in a recent Observations post, a subset of sleepwalkers, comprising about 2 percent of the general population in North America and Europe, may be at risk for one of three disorders associated with sleep violence, and related incidents have ranged from running and kicking to assault and even murder. Daisy Yuhas writes:

Because various disorders can underlie sleep violence, investigating incidents is understandably challenging. Michel Cramer Bornemann, [MD,] a sleep specialist at the Minnesota Regional Sleep Disorders Center, and his colleagues at the center’s Sleep Forensics Associates have handled more than 200 forensic cases related to sleep disorders, often at the request of law enforcement. Of these, only arousal disorders have been associated with criminal behavior during sleepwalking. He estimates that about a third of cases the forensics associates encounter involve sleep drugs, such as Ambien, which may increase the risk of experiencing an arousal disorder.

Ongoing research to better understand the brain states of those afflicted by such disorders is highlighted in a feature (subscription required) in the latest issue of Scientific American. The article also discusses symptoms of arousal disorders, wherein a person “operates in a mental state between wakefulness and sleep, carrying out complex behaviors with no evident conscious awareness.” Other disorders associated with sleep violence include nocturnal frontal lobe epilepsy and rapid eye movement (REM) sleep behavior disorder.

Previously: Stanford study shows millions of Americans are prone to sleepwalking and Video: Patient does art while sleepwalking
Photo by practicalowl

Your mother might have warned you about fungal infections and other horror stories from the pedicure chair. At least mine did. Being a ballet dancer, I wouldn’t set foot in a nail salon for years, not trusting anyone to treat my feet properly. I hoarded my hard-earned calluses and once even performed my own minor surgery, unsuccessfully, and vowed never again to take a sharp tool to my feet. I’ll spare you the gory details.

But for those who still enjoy indulging in a foot-pampering experience, U.S. New offers tips today for decreasing your risk of infection at the spa or considering taking your business to a podiatrist. Recommendations include avoiding razors (yes!) and skipping the popular fish pedicure. Also, beware soaking your feet:

For your part, hold off on the foot bath if you have any cuts, scrapes, scabs, bruises, or open sores on your legs or feet as broken skin eases the passage of germs into your body. The EPA and CDC also include bug bites on this list, which seems to ensure no one could ever possibly be fit for a pedicure, given the coinciding seasons of pedicures and bugs. Also, skip the pre-pedicure shave to avoid causing any nicks. The APMA [American Podiatric Medical Association] suggests scheduling your spa pedicure early in the morning, since “salon foot baths are typically cleanest earlier in the day.” [Hillary Brenner, DPM, a podiatric surgeon] advises patronizing nail salons that use disposable plastic bins inside the foot bath to lower your risk of infection.

Previously:Examining the effectiveness of hand sanitizers
Photo by Luiz Gustavo Leme

On today’s CBS This Morning, Sal Khan, founder and executive director of Khan Academy, discussed his non-profit organization’s mission to provide free world-class education to anyone anywhere. Since its founding six years ago, Khan Academy has made available more than 3,200 online educational videos, and soon its materials will be translated into 12 languages.

Speaking with Charlie Rose and Gayle King for the interview, Khan described plans for improving and expanding his organization and noted that Stanford’s medical school is going to launch several courses. The courses will be “free for the world, as well, and we’re just going to try to make the entire experience as engaging as possible,” Khan said.

Medical experts have advised wearing sunscreen outdoors and staying out of tanning beds altogether to reduce preventable skin damage and other health risks. But those still aiming to look like the Bronze Idol from the 19th century ballet La Bayadère may also want to hold off on even a sunless tanning approach. Evidence suggests that spray tanning may not be a safe alternative to ultraviolet exposure.

Today, ABC News reports that spray tans’ active chemical, dihydroxyacetone (DHA), may damage DNA and cause genetic alterations. A literature review performed by six medical experts with expertise spanning dermatology, toxicology and pulmonary medicine has raised questions about the safety of DHA. The chemical was approved by the U.S. Food and Drug Administration in 1970s for external use; back then, it was tanning lotions, not sprays, that were ubiquitous.

Scientists worry that when sprayed without protecting body cavities and mucous membranes, the chemical could be inhaled, ingested, or absorbed through the skin into the bloodstream – all falling outside of the approved use of DHA and possibly making the body vulnerable to its harmful effects.

From today’s article:

[Rey Panettieri, MD], like all the experts ABC News consulted with, said more studies should be done. He emphasized the available scientific literature is limited. Still, he said, he has seen enough to say the warning signs of serious health concerns exist.

“These compounds in some cells could actually promote the development of cancers or malignancies,” he said, “and if that’s the case then we need to be wary of them.”

The full investigative report is worth a read.

Previously: Study shows link between indoor tanning and common skin cancer and Intense, rapid sun tanning may increase skin cancer risk
Photo by Dr Stephen Dann

A new study examining two hallmarks of meditation found that openness to one’s emotional experiences may play a larger role than mindfulness of the present in increasing a practitioner’s self-control.

For a paper slated for publication in Social Cognitive and Affective Neuroscience, University of Toronto researchers studied the Error Related Negativity (ERN), described as an “uh-oh” response: a pre-conscious electrical signal to the brain that appears before we are aware of an error being committed. As explained in a Futurity.org article:

For the study, participants were asked about their experience meditating, and took tests that measured how mindful they were of the present moment, and also how aware and accepting they were of their emotions.

The participants were then hooked up to an electroencephalograph and given something called the Stroop test.

….

Meditators were generally better than non-meditators at the test, and also had generally stronger ERN responses. Looking further, the best performers were those who scored highest on emotional acceptance, and that mindful awareness—the more cognitive aspect of mindfulness–had less to do with success on the test.

Reading about self-control and mindfulness brought to mind the work of Stanford’s Kelly McGonigal, PhD, author of the book The Willpower Instinct and an instructor in Stanford’s Health Improvement Program. I asked McGonigal for her thoughts on the study and was told, “These new findings are consistent with previous research showing that meditation trains the brain for greater focus and self-control.” She went on to say:

What I find most interesting about this study is that of all the qualities mindfulness meditation trains, it was emotion acceptance that best predicted impulse control. Most people think that meditation is about getting rid of thoughts and emotions — pushing them away to experience a still mind. In reality, mindfulness meditation trains us to not get caught up in them. This study is a good reminder of that.

McGonigal also shared her personal take on one part of the study:

I’m not sure I agree with the study researcher’s interpretation that meditators do better on this task because they are more sensitive to their own emotions, including the bad feeling of making a mistake. The lead researcher speculates that the meditators feel worse about making an error and are motivated to avoid it. I think it’s more likely that they don’t need to defend against awareness of being wrong.

Previously: The science of willpower
Photo courtesy of Bliss Flow Yoga

In much of the developing world, health hazards involving food extend beyond the edible substances being consumed. Makeshift stoves fueled by crop scraps and animal dung emit plumes of black smoke that fill homes and can cause pneumonia and other acute respiratory infections. Such cooking methods are used by nearly three billion people and contribute to an estimated two million death a year, according to data from the World Health Organization.

In a paper published today in the Proceedings of the National Academy of Sciences, Grant Miller, PhD, associate professor of medicine at Stanford’s Center for Primary Care and Outcomes Research, and colleagues explore why people are reluctant to switch to safer cookstoves, many of which have chimneys that funnel smoke out of a home. A Stanford Report article describes the work:

In the first of two studies, Miller – joined by Yale researchers and Lynn Hildemann, a Stanford engineering professor affiliated with the university’s Woods Institute for the Environment – surveyed about 2,500 women who cook for their families in rural Bangladesh.

Nearly all of the women use traditional stoves, and 94 percent of them said they know the smoke from their stoves can make them sick. But 76 percent said the smoke is less harmful than polluted water, and 66 percent said it wasn’t as dangerous as rotten food.

“People know their cookstoves are bad, but they don’t think cookstoves are the most important problem they face,” Miller said. “They’d rather spend their money fixing those things and getting their kids into a good school than buying a new cookstove.”

Investigators found among the Bangladeshi women they surveyed that concerns such as fuel costs and cooking time held more importance than reducing pollution when considering a stove. Miller, senior author of the study, commented on the findings, saying:

A big implication is that the health education and social marketing approaches aren’t going to work… You need to get inside the heads of the users and figure out what they really want and value – even if unrelated to smoke and health – and then give it to them.

Previously: New insight into asthma-air pollution link