In a comparison of complementary and alternative medicine (CAM) use by adults in 1997 and 2002, researchers from Harvard Medical School found more than one in three U.S. adults (36.5 and 35.0 percent, respectively) used at least one form of CAM.
The continued widespread use of individual and multiple CAM therapies underscores the need to rigorously evaluate the safety, efficacy, and cost-effectiveness of these approaches, according to the study's lead author Hilary Tindle, Harvard Medical School (HMS) research fellow, and co-author David Eisenberg, director of the Division for Research and Education in Complementary and Integrative Medical Therapies and the Osher Institute at HMS.
The study results appear in the January/February issue of the medical journal Alternative Therapies in Health and Medicine.
The study compared results of the National Health Interview Survey in 2002 and a survey conducted by researchers at HMS (Eisenberg et al.) in 1997. The two surveys were similar but not identical. Prior to this study, there had been no head-to-head comparison using a common definition of CAM.
"Our research over the past 14 years has shown a consistent level of usage by adult Americans," said Dr. Eisenberg. "While there have been a few notable changes in which CAM therapies people are using, the overall number of adults employing some type of CAM has remained remarkably consistent since we began our surveys in 1990. This says to us that these therapies are part of the fabric of modern day health care, and that we need to do more research on their safety and effectiveness - just as we would with any other therapeutic options," concludes Eisenberg.
Over the five-year period between the two most recent surveys, the total number of Americans using any CAM therapy remained fairly stable at 72 million. However, there were changes in the choice of CAM therapies used.
The largest change was a 50 percent jump in the use of herbal supplements, growing over the five years from 12.1 percent of adults reporting usage in 1997 to 18.6 percent -- or 38 million adults -- in 2002. The practice of yoga increased 40 percent over the same period, growing from 3.7 percent in 1997 to 5.1 percent-- over 10 million adults-- in 2002.
Use of CAM therapies such as acupuncture, biofeedback, energy healing, and hypnosis remained essentially unchanged between 1997 and 2002, while the use of homeopathy, high-dose vitamins, chiropractic, and massage therapy declined slightly. Since many CAM therapies are paid out-of-pocket by consumers, the authors suggest that some of these declines may be due, at least in part, to a downturn in the U.S. economy from 1997 to 2002.
The ways in which several CAM therapies are used also appear to have changed. For example, only 5 percent of people who used herbs saw a practitioner of herbal medicine in 2002, compared to 15 percent in 1997. "Such changes are important considering that other research has shown that 60 to 70 percent of patients who use CAM therapies do not disclose it to their physician," says lead author Dr. Tindle. "This is especially critical as more becomes known about the adverse effects associated with individual dietary supplements as well as their interactions with prescription drugs".
Despite variability seen in previously published reports about overall CAM use, the authors conclude the use of CAM by one third of U.S. adults from 1997 to 2002 appears to have been steady, reconfirming results from the first national survey in 1990.