FIVE STUDIES YOU MAY HAVE MISSED

What's becoming our regular Friday feature.  What new conclusions are out there in the medical world today?  Read on:

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Here's a roundup of five medical studies published this week that might give you new insights into your health, mind and body. Remember, correlation is not causation – so if a study finds a connection between two things, it doesn't mean that one causes the other.

'Healthy obesity' doesn't exist
Journal: Journal of the American College of Cardiology
Can you be fat and fit? Recent research has suggested that the answer is no - obesity is never healthy. A new study supports that conclusion.
Researchers examined data on 14,828 healthy Korean adults. They found that, compared to people with normal weight, obese participants had a higher prevalence of subclinical coronary atherosclerosis, meaning early plaque buildup in their arteries. This condition, if not managed, can result in heart attack and sudden cardiac death.
"Obese individuals who are considered 'healthy' because they don't currently have heart disease risk factors should not be assumed healthy by their doctors," said lead study author Dr. Yoosoo Chang in a statement. "Our research shows that the presence of obesity is enough to increase a person's risk of future heart disease and that the disease may already be starting to form in their body. It's important that these people learn this while they still have time to change their diet and exercise habits to prevent a future cardiovascular event."
Read more from EurekAlert!
Pig bladder used to regrow muscle
Journal: Science Translational Medicine
Regenerative medicine saw a breakthrough this week: A study showed how muscle could be regrown in mice and humans.
The human participants were five men who had lost 58% to 90% of one of their leg muscles. To treat them, researchers used a a scaffold made from a pig bladder. This scaffold coaxed stem cells in the men's remaining leg muscle to grow into muscle, too.
"Biological scaffolds, when they degrade, release signal molecules," lead author Dr. Stephen Badylak, of the University of Pittsburgh, told LiveScience. "They can tell cells to do things like divide and line up in a certain way."
Three of the patients showed significant improvement, while the other two had less or no benefit from the procedure.
Researchers are trying the technique in other patients.
Read more from LiveScience
Manicure lamps linked to small cancer risk
Journal: JAMA Dermatology
If you frequent the nail salon, this news is for you: Researchers say there could be a cancer risk associated with the ultraviolet lamps used for nail polish drying. But the risk varies according to the kind of bulb used at the nail salon.
Dr. Lyndsay Shipp and colleagues calculated that at some salons, it may only take 24 visits to accumulate DNA damage caused by ultraviolet radiation that could cause cancer. At other salons, it would take 625 visits.
More research is needed, Shipp told TIME.com. In the meantime, rest assured one manicure won't give you cancer. But if you're concerned, or have a family history, you could wear sunscreen for the ultraviolet light, or just air-dry your nails.
Read more from TIME.com
Higher antidepressant doses linked to self-harm in teens, young adults
Journal: JAMA Internal Medicine
Young patients are at risk of harming themselves if they receive doses of antidepressants that are higher than recommended, a new study says.
There has been mixed evidence on the subject of antidepressant and suicidal behavior among youth in the past. A government review found an association with self-harm, prompting a so-called "black box warning," or warning on the drug's label. But other studies have found no link, and argue that the benefits of these drugs outweigh the risks.
This study, however, specifically examines the connection to dose levels. It looked at three popular drugs: Celexa, Zoloft and Prozac.
Researchers found a risk in self-harm associated with higher-than-recommended doses in patients under age 24. They did not find the same effects in individuals over age 25, or those who took lower drug dosages.
Further study is needed. In the meantime, doctors are recommended to start young patients slowly on antidepressants, at low doses, CBS reports.
Read more from CBS.com
Of mice smelling men: Sex of researcher may affect lab rodents' behavior
Journal: Nature Methods
Rodents get stressed out in the presence of human males, but less so females, a new study suggests.
The stress hormone corticosterone went up in mice and rats when they were put with a man alone in a room, or were given a T-shirt that a man had worn. Researchers did not observe this high level of stress associated with a woman or female-worn shirt.
This difference could be significant because this hormone decreases the rodents' response to pain, so the results of scientific studies involving rodents could be skewed, depending on who was in the room with the critters.
Apparently, time can reduce the rodent stress effect.
“The ideal solution would be for the male researchers to sit in the room with the rodents for 30 to 60 minutes before conducting experiments,” study author and McGill University psychologist Jeffrey Mogil told the New York Times. “But no one is going to do that.”
Read more from the New York Times