WASHINGTON (Reuters) – About four in 10 U.S. adults and one in nine children are turning to unconventional medical approaches for chronic pain and other health problems, health officials said on Wednesday.

Back pain was the leading reason that Americans reported using complementary and alternative medicine techniques, followed by neck and joint pain as well as arthritis, according to the survey by the National Institutes of Health and the U.S. Centers for Disease Control and Prevention.

About 38 percent of adults used some form of complementary and alternative medicine in 2007, compared to 36 percent in 2002, the last time the government tracked at the matter.

For the first time, the survey looked at use of such medicine by children under age 18, finding that about 12 percent used it, officials said. The reasons included back pain, colds, anxiety, stress and attention deficit hyperactivity disorder, according to the survey.

The risks for children using these are unclear, they said.

Complementary medicine is used together with conventional treatment, while alternative medicine is used instead. This includes such things as herbal medicines and other natural products, chiropractic techniques, acupuncture, massage, meditation and others.

Many people feel these may work better for them than typical medical approaches, with fewer bad side effects. And so-called natural products have become big business, too, with various herbal medicines and others emerging as lucrative products.

“As I look at this data, what I’m most struck with is how much people are turning to CAM (complementary and alternative medicine) approaches as part of the management of chronic pain conditions, particularly chronic back pain, but also neck pain and musculoskeletal pain and headache,” said Dr. Josephine Briggs, director of the U.S. National Center for Complementary and Alternative Medicine at the NIH.

“And from my days as an internist seeing patients in my office, I know that these are conditions that are hard to manage and tough to treat,” Briggs told reporters.

Chiropractic care, acupuncture and massage therapy are among the complementary and alternative medicine techniques used for chronic pain, NIH researcher Richard Nahin said.

The survey results were based on responses from about 23,000 adults and 9,500 children nationwide.

Overall, the most common category of complementary and alternative medicine used was natural products such as herbal medicines and certain other types of dietary supplements other than vitamins and minerals.

Among these natural products used by adults, fish oil was the most commonly used. Nahin said it is used for such reasons as high cholesterol and high blood pressure.

Nahin said use of complementary and alternative medicine seems to be remaining at a significant but stable level, with most of the recent increases among those age 60 and up.

Deep breathing exercises, meditation and massage therapy all showed significant increases among adults. Overall, women and people with higher levels of education were more likely to use complementary and alternative medicine techniques.

Echinacea, a medicinal plant sometimes used to treat or prevent colds, was the most common of the natural products used by children, according to the survey. Echinacea use dropped among adults from 2002 to 2007, Nahin said.

(Editing by Maggie Fox and Cynthia Osterman)