A growing number of kids and adults in the United States are practicing yoga, according to new results from a government survey.

Over the last decade, the percentage of U.S. adults who said they practiced yoga increased from 5.1 percent in 2002 to 9.5 percent in 2012, according to the survey, which was conducted by the National Institutes of Health and the Centers for Disease Control and Prevention. In 2012, about 21 million adults practiced yoga, which is nearly double the number of people practicing in 2002, the researchers said.

Yoga among children is also on the rise: the percentage of children ages 4 to 17 who do yoga increased from 2.3 percent in 2007 to 3.1 percent in 2012, which translates to about 400,000 more kids practicing yoga.

Part of the reason for the rise may be the increase in the number of yoga studios and instructors that has occurred in recent years, making yoga more accessible to a larger number of people, the researchers said.

In addition, there are now more studies suggesting that certain mind-and-body practices, such as yoga, can help people manage pain and reduce their stress, the researchers said. [Best Yoga Apps]

"The survey data suggest that consumers are paying attention to medical evidence and using it to inform their decisions,” Dr. Josephine P. Briggs, director of the NIH’s National Center for Complementary and Integrative Health, said in a statement.

Overall, about one-third (34 percent) of adults and 11.6 percent of children used some form of complementary medicine in 2012, according to the survey. Complementary medicine involves treatments that are outside of mainstream medical practice, and that are not always proven to affect people's health. Although sometimes called "alternative medicine," studies have found that these treatments, for the most part, "are not used as an alternative instead of proven therapies, but as a complement to conventional care," Briggs said.

The most popular type of complementary medicine in the survey was taking dietary supplements, besides vitamins or minerals; they were used by about 18 percent of adults and 5 percent of children.

The survey also found that use of fish oil is on the rise. Among adults, the use of fish oil supplements increased from 4.8 percent in 2007 to 7.8 percent in 2012, and among children, fish oil use increased from 0.7 percent to 1.1 percent over the same time period.

In contrast, use of some dietary supplements has declined. For example, use of the supplement echinacea decreased 1.3 percentage points among adults, and 0.4 percentage points among children, over a five-year period.

These shifts in supplement use align to some extent with recent scientific findings. "Since the mid-2000s, several well-designed clinical trials have not seen any benefit of taking echinacea to treat or prevent the common cold. [But] during this same time period, data supporting the use of fish oil for heart health have been accumulating," researchers wrote in a recent report released by the CDC's National Center for Health Statistics.

The new findings are based on data from more than 88,000 U.S. adults who were surveyed in 2002, 2007 and 2012, and 17,000 adults who were interviewed about their children in 2007 and 2012.

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