5 studies you may have missed

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.

Blood test may diagnose sports injuries to the brain
Journal: JAMA Neurology

Sports concussions have received a lot of attention recently, as evidence mounts that repetitive injuries to the brain can have damaging long-term consequences. But the science of sports-related head injuries, including how to measure recovery and decide when it's OK for a patient to play again, needs work.

This study proposes using blood biomarkers to diagnose sports-related concussions. To study the phenomenon, researchers used 280 players from 12 teams in the Swedish Hockey League, the top professional ice hockey league in Sweden.

Researchers say a blood test measuring a protein called tau could help determine the severity of a concussion, whether there could be long-term consequences and when a patient can return to play. The test could evaluate severity just one hour after injury, they said.

"Concussions are a growing international problem," lead study author Henrik Zetterberg of the Sahlgrenska Academy at the University of Gothenburg told Reuters Health. "The stakes for the individual athlete are high, and the list of players forced to quit with life-long injury is getting ever longer."

Read more from Reuters Health

More adults than ever on ADHD drugs
Report from Express Scripts

Amid concerns about overmedicating children, a new report suggests that the number of adults taking drugs for attention-deficit hyperactivity disorder (ADHD) rose more than 50% between 2008 and 2012.

Women between the ages of 26 and 34 in particular have experienced a marked rise in ADHD medications, with 85% more taking the drugs in 2012 than in 2008.

What's going on here? It could be that these women with ADHD were overlooked as children because girls are less likely to show disruptive behavior at young ages than boys. Or, women may be using the medications inappropriately, like as appetite suppressants, TIME.com reported.

Read more from TIME.com

Drinking during first term of pregnancy especially harmful
Journal: Journal of Epidemiology and Community Health

Major medical organizations such as the American College of Obstetricians and Gynecologists have said time and again: Do not drink during pregnancy. But researchers are still looking into the specifics of when alcohol might have the most detrimental effect.

In the latest study, the likelihood of premature birth increased among women who drank moderately during the first months of pregnancy.

More than 1,200 women in Leeds, United Kingdom, participated in the study. Those who drank more than two units of alcohol - about one pint - twice a week had a doubled risk of premature birth.

"This is a very sensitive issue. We don't want women who are pregnant now to panic - the individual risk is actually low," Camilla Nykjaer, one of the researchers at the University of Leeds, told the BBC. "They shouldn't drink. They should stop drinking if they have been drinking during the pregnancy."

The United Kingdom's National Health Service says women shouldn't drink during pregnancy, but if they do, limit it to two units once or twice a week, and don't get drunk.

But women in the United States, take note: U.S. health officials say no amount of drinking during pregnancy has been proven safe.

Read more from the BBC

Yes, healthy foods can sell at concession stands
Journal: Journal of Public Health

What happens when you start selling healthy alternatives at concession stands? Based on one study at a high school, it seems customers don't turn away.

Researchers analyzed sales data from concessions at Muscatine High in Iowa, where healthy snacks were sold during football, swimming and volleyball events. Healthier ingredients were used in popcorn and nachos, too. The standard offerings such as pizza, hot dog and candy bars were still available.

Researchers found that sales, revenues and profits were generally stable. Sales per varsity football game actually went up 4% in 2009, when the changes were made, compared to the year before.

"If you're a concession-stand sponsor, and you want people to eat better, and you want to make more money, add at least five healthy items," Brian Wansink, the Cornell lab's director and a marketing professor, said in a statement. "There's got to be a critical mass, and we find that five's a very lucky number, and 10 is even better."

Read more from IowaNow

Vaginal gel may prevent HIV infection
Journal: Science Translational Medicine

A new vaginal gel may potentially protect against HIV when applied up to a few hours after sex, according to a study published Wednesday. All preventative gels currently on the market must be applied before sex, which can make compliance tough for women.

Researchers conducted testing on pigtailed macaques - monkeys with menstrual cycles similar to women. The vaginal gel protected five out of six monkeys from HIV when applied three hours after virus exposure and two of three monkeys when applied 30 minutes before. The gel works after exposure by preventing HIV integration into DNA, a process that begins around six hours after infection.

Applying the gel after sex gives the users more control, study authors say. In order to use the gel, people don't need to anticipate having sex beforehand or rely on their partner's acceptance of it. Researchers believe these advantages could help improve compliance and effectiveness of vaginal gel use.

“We are excited because this provides a whole new option that was previously nonexistent,” says lead study author Walid Heneine of the Centers for Disease Control and Prevention.

More trials and tests are needed to see if the gel will be effective in women.