Using factor analysis to create complementary and alternative medicine domains: an examination of patterns of use

Previous research on complementary and alternative medicine (CAM) in the United States has relied heavily on the National Center for Complementary and Alternative Medicine's (NCCAM) domains of CAM but with noted limitations. We conducted a multifaceted examination of previous CAM domains and tested if they represent actual patterns of CAM use. The data come from the 2002 United States' National Health Interview Survey and include 30,923 adults. Outcome measures included 20 types of CAM used in the last 12 months. Both exploratory and confirmatory factor analysis were used to test how CAM modalities should be categorized. Results indicate that prayer should be created as a new domain apart from Mind-Body Medicine. Herbs and vitamins fit best with Alternative Medical Systems while acupuncture best fits with chiropractic and massage. These findings suggest that how types of CAM have been previously categorized in earlier research is inconsistent with actual patterns of CAM utilization.These findings provided a framework for conducting and analyzing future CAM research, both in the USA and in other countries, and should be used in future research to try to explain and understand the variation and predictors of CAM utilization.