Health Buzz: HIV Rate Among Gay Men Is 1 in 5

How different types of yoga affect health; is child obesity an infectious disease?

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Study: 20 Percent of Gay Men Have HIV, Half Don't Know They're Infected

About 20 percent of gay and bisexual men are HIV-positive—but nearly half don't know it, a new study suggests. More than 8,000 men in 21 cities were tested for the virus in 2008, and 44 percent were unaware they were infected, according to the analysis by the Centers for Disease Control and Prevention. Least likely to know they had HIV? Young, sexually active gay men—and those in minority groups. Baltimore's gay population had a 38 percent infection rate, the highest among the cities included in the study. More than 56,000 Americans become infected with HIV each year, and 18,000 die of AIDS annually, the CDC reports. "This study's message is clear: HIV exacts a devastating toll on men who have sex with men in America's major cities, and yet far too many of those who are infected don't know it," Kevin Fenton, director of the CDC's National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, told The Washington Post.

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  • Benefits of Yoga: How Different Types Affect Health

    Perhaps it's a testament to the power of yoga that so many spin-offs have emerged—dozens since it originated some 6,000 years ago. There's laughter yoga, which turns humor into a healing power, AcroYoga, which revolves around flying, and hot yoga, taught in a 105-degree studio. Even naked yoga is catching on, described by followers as a therapeutic way to burst out of the confines of clothing, U.S. News reports.

    Research bolsters the claims made for the trend: Yoga protects the brain from depression, an August study found; three sessions per week boosted participants' levels of the brain chemical GABA, which typically translates into improved mood and decreased anxiety. "People who have disorders like depression and anxiety can definitely benefit from yoga, because it returns [GABA] levels to the normal range," says study author Chris Streeter, an assistant professor of psychiatry and neurology at Boston University School of Medicine. Streeter says yoga can be used to complement—not substitute—drug treatment for depression.

    Past research has explored yoga's effect on epilepsy, heart disease, cancer, and multiple sclerosis, among other conditions. A 2004 Yale University School of Medicine study, for instance, found that people who practice yoga reduced their blood pressure, pulse, and risk of heart disease. The health benefits likely come about—at least in large part—because yoga helps people better manage stress, says Janice Kiecolt-Glaser, a professor with the Institute for Behavioral Medicine Research at Ohio State University College of Medicine. "Yoga has a meditation component that is not true of other exercise. That aspect makes a difference," she says. [Read more: Benefits of Yoga: How Different Types Affect Health.]

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    • Is Child Obesity an Infectious Disease?

      Is obesity contagious? The surprising news that some obese children are more apt to carry a common cold virus than slimmer children has many people wondering. If the potential link between the adenovirus 36 and childhood obesity turns out to be real, then someday new obesity treatments might be tailored to attack the virus to treat or prevent childhood obesity, an epidemic that affects 17 percent of American children and teenagers.

      There have been other unexpected discoveries of microbes causing disease, the most famous being the bacterium Heliobactor pylori, which turned out to be the major cause of stomach ulcers. In the early 20th century, ulcers were thought to be caused by stress and excess stomach acid, and sufferers were told to rest and eat bland food, writes U.S. News contributor Nancy Shute. In 1982, when two Australian physicians first said H. pylori caused ulcers, the international medical community scoffed. It took more than a decade for that fact to be accepted as true. An H. pylori test and antibiotics are now the recommended treatment for ulcers.