Complementary and Alternative Medicine
Use Among Adults
Objective—This report presents selected estimates of complementary and alternative medicine (CAM) use among U.S. adults, using data from the 2002 National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention’s (CDC) National Center for Health Statistics (NCHS).
Methods—Data for the U.S. civilian noninstitutionalized population were collected using computer-assisted personal interviews (CAPI). This report is based on 31,044 interviews of adults age 18 years and over. Statistics shown in this report were age adjusted to the year 2000 U.S. standard population.
Results—Sixty-two percent of adults used some form of CAM therapy during the past 12 months when the definition of CAM therapy included prayer specifically for health reasons. When prayer specifically for health reasons was excluded from the definition, 36% of adults used some form of CAM therapy during the past 12 months.
The 10 most commonly used CAM therapies during the past 12 months were use of prayer specifically for one’s own health (43.0%), prayer by others for one’s own health (24.4%), natural products (18.9%), deep breathing exercises (11.6%), participation in prayer group for one’s own health (9.6%), meditation
(7.6%), chiropractic care (7.5%), yoga (5.1%), massage (5.0%), and diet-based therapies (3.5%). Use of CAM varies by sex, race, geographic region, health insurance status, use of cigarettes or alcohol, and hospitalization.
CAM was most often used to treat back pain or back problems, head or chest colds, neck pain or neck problems, joint pain or stiffness, and anxiety or depression.
Adults age 18 years or over who used CAM were more likely to do so because they believed that
CAM combined with conventional medical treatments would help (54.9%) and/or
they thought it would be interesting to try (50.1%). Most adults who have ever used
CAM have used it within the past 12 months, although there is variation by CAM
Complementary and alternative medicine (CAM) refers to a group of diverse medical and health care methods ,therapies, and products that are not presently considered to be part of conventional medicine. The U.S. public’s use of CAM increased
substantially during the 1990s (1–11). This high rate of use translates into large out-of-pocket expenditures on CAM. It has been estimated that the U.S. public spent between $36 billion and $47 billion on CAM therapies in 1997 (5). Of this amount, between $12.2 billion and $19.6 billion was paid
out-of-pocket for the services of professional CAM health care providers
such as chiropractors, acupuncturists, and massage therapists. These fees are
more than the U.S. public paid out-of pocket for all hospitalizations in 1997
and about half that paid for all out-of pocket physician services (12).
Explanations for this growth in CAM use have been proposed, including
marketing forces, availability of information on the Internet, the desire of
patients to be actively involved with medical decision making, and
dissatisfaction with conventional (western) medicine (13).
This dissatisfaction may be related to the lack of conventional medicine to
adequately treat many chronic diseases and their symptoms such as debilitating pain (1). Rates of CAM use are also exceptionally high among individuals with life threatening illnesses such as cancer (14) or HIV (15). It appears that the majority of people use CAM as a
complement to conventional medicine, not as an alternative (1,3,5).
As used by the U.S. public, CAM consists of many heterogeneous systems
of medicine as well as numerous stand-alone therapies (16). Several
systems of CAM are practiced as part of the health care system in U.S.
immigrants’ countries of origin (17). For example, Ayurveda is practiced in India at a national level within the Federal health system. Traditional Chinese
medicine, which includes acupuncture, acupressure, herbal medicine, tai chi,
and qi gong, is often practiced in the same hospitals or clinics as conventional
medicine in China. Kampo, the system of traditional herbal medicine in Japan,
is covered by the national health insurance plan and is practiced by many
medical doctors (18). Immigrants from these and other countries of origin may continue to rely on CAM as part of their
medical treatment in the United States even as they seek care from
conventional health care providers.
Some of these systems may eventually prove to be low cost health care options for use by the U.S. public. Despite the diverse ways in which
these systems and therapies developed, they appear to have several
characteristics in common: the use of complex interventions, often involving
the administration of many medications or medicinal substances at the same
time; individualized diagnosis and treatment of patients; an emphasis on maximizing the body’s inherent healing ability; and treatment of the ‘‘whole’’
person by addressing their physical, mental, and spiritual attributes rather
than focusing on a specific pathogenic process as emphasized in conventional
Notwithstanding the growing scientific evidence that some CAM
therapies may be effective for specific conditions (20,21), the public’s wide use of many untested CAM therapies might
have unanticipated negative consequences. For example, the U.S.
Department of Health and Human Services banned the sale of the herbal
supplement ephedra in 2003 after concluding that the risks associated with
use of this product by the general public greatly outweighed any potential benefit (22). It has been found that other herbal
products interact or interfere with the normal pharmacology of some
pharmaceutical drugs with potentially fatal consequences (23).
CAM users often do not share information about such use with their conventional health care providers (5), thereby increasing the possibility of serious interactions.
Even when conventional health care providers are aware that their patients
are taking herbal products, serious interactions could result if providers are
unfamiliar with the scientific literature on CAM. Understanding the prevalence and reasons for CAM use is a first step toward improving communication between health care providers and their patients.
This report is based on a CAM
supplement that was administered as
part of the sample adult questionnaire of
the 2002 NHIS.
The report focuses on
who uses CAM, what is used, and why
it is used. It also examines the
relationship between the use of CAM
and the use of conventional medical
In particular, the report examines the relationship of CAM use
and demographic and health behaviors
among groups not previously studied in
detail, including race and ethnic groups,
the economically disadvantaged, and the
The 2002 NHIS included
questions that asked respondents about
their use (ever and during the past 12
months) of 27 different CAM therapies.
This report defines CAM broadly by
including therapies or practices that may
not be considered CAM, such as prayer
specifically for health purposes and
high-dose vitamin therapy, and examines
the use of these practices in specific
The statistics shown in this report
are based on data from the Alternative
Health/Complementary and Alternative
Medicine supplement, the Sample Adult
Core component, and the Family Core
component of the 2002 NHIS (24). The
NHIS, one of the major data collection
systems of CDC’s NCHS, is a survey of
a nationally representative sample of the
civilian noninstitutionalized household
population of the United States. Basic
health and demographic information
were collected on all household
members. Adults present at the time of
the interview are asked to respond for
themselves. Proxy responses are
accepted for adults not present at the
time of the interview and for children.
Additional information is collected on
one randomly selected adult age 18
years or over (sample adult) and one
randomly selected child age 0–17 years
(sample child) per family. Information
on the sample adult is self-reported
except in rare cases when the sample
adult is physically or mentally incapable
of responding, and information on the
sample child is collected from an adult
family member who is knowledgeable
about the child’s health.
The Alternative Health/
Complementary and Alternative
Medicine supplemental questionnaire
included questions on 27 types of CAM
therapies commonly used in the United
States (table 1). These 27 CAM
therapies included 10 types of providerbased
CAM therapies (e.g., acupuncture,
chiropractic care, folk medicine), as well
as 17 other CAM therapies for which
the services of a provider are not
necessary (e.g., natural products, special
diets, megavitamin therapy). The CAM
supplement, unlike earlier surveys,
includes specific types of CAM diets
such as Atkins, Macrobiotic, Ornish,
Pritikin, and Zone; a comprehensive
range of mind-body therapies, including
biofeedback, deep breathing techniques,
guided imagery, hypnosis, progressive
relaxation, qi gong, tai chi, and yoga;
and the use of prayer for health
purposes. Inclusion and development of
the 2002 supplement was supported, in
part, by the National Center for
Complementary and Alternative
Medicine (NCCAM), National Institutes
of Health (NIH).
This report is based on data from 31,044 completed interviews with sample adults age 18 years and over, representing a conditional sample adult response rate of 84.4% and a final sample adult response rate of 74.3%.
Procedures used in calculating response rates are described in detail in ‘‘Appendix I’’ of the Survey Description of the NHIS data files (24). Because the CAM questions were administered as part of the Sample Adult questionnaire and only about 1.4% of the sample adults did not answer any questions in
the CAM supplement, a separate response rate for the CAM questions
was not calculated.
All estimates (percents and frequencies) and associated standard errors shown in this report were generated using SUDAAN, a software package designed to account for a complex sample design such as that used by the NHIS (25). All estimates were weighted using the sample adult record weight, to represent the U.S. civilian noninstitutionalized population
age 18 years and over.
Most estimates presented in this report were age adjusted to the year 2000 U.S. standard population age 18 years and over (26,27). The SUDAAN
procedure PROC DESCRIPT was used to produce age-adjusted percentages and their standard errors. Age adjustment was used to allow comparison of
various sociodemographic subgroups that have different age structures. The
estimates found in this report were age adjusted using the age groups 18–24
years, 25–44 years, 45–64 years, and 65 years and over, unless otherwise noted. (See ‘‘Technical Notes’’ for details.)
Age-adjusted estimates were compared using two-tailed statistical
tests at the 0.05 level. No adjustments were made for multiple comparisons.
Terms such as ‘‘greater than’’ and ‘‘less than’’ indicate a statistically significant difference. Terms such as ‘‘similar’’ or ‘‘no difference’’ indicate that the statistics being compared were not significantly different. Lack of comment regarding the difference between any two statistics does not mean that the difference was tested and found to be not significant.
Most statistics presented in this report can be replicated using NHIS
public use data files and accompanying documentation available for
downloading from the NCHS Web site at: http://www.cdc.gov/nchs/nhis.htm.
Variables identifying metropolitan statistical area (MSA), urban/rural residence, and State, which was used to create the category ‘‘Pacific States,’’ are not included in the public use data files to protect respondent confidentiality.
Therefore, corresponding estimates cannot be replicated. Many of the
references cited in this report are also available via the NCHS Web site at:
A major strength of the data on complementary and alternative medicine in the NHIS is that they were collected for a nationally representative sample of U.S. adults, allowing estimation of CAM use for a wide variety of population subgroups. The large sample size also facilitates investigation of the association between CAM and a wide range of other self-reported health characteristics included in the NHIS such as health behaviors, chronic health conditions, injury episodes, access to medical care, and health insurance coverage.
The CAM data collected in the 2002 NHIS are a significant improvement over the CAM data collected in the 1999 NHIS. The 1999 NHIS included only one question that asked respondents if they had used (during the past 12 months) any of the 11 listed therapies or some other CAM therapy that they were then asked to name. The 2002 NHIS included questions that asked respondents about their use (ever and during the past 12 months) of 27 different CAM therapies.
For therapies used during the past 12 months, respondents were asked more detailed questions such as the health problem or condition being treated with the therapy, the reason(s) for choosing the therapy, whether the costs of the therapy were covered by insurance, their satisfaction with the treatment, and whether any of their conventional medical professionals knew they were using the therapy.
The CAM questions have several limitations. First, they are dependent upon respondents’ knowledge of CAM therapies and/or their willingness to report use accurately. Secondly, the collection of CAM data at a single point in time results in an inability to produce consecutive annual estimates for CAM use so that changes can not be tracked over time, and it reduces the ability to produce reliable estimates of CAM use for small population subgroups as this
would require a larger sample and/or
more than 1 year of data.
Overall, in 2002, about 62% of U.S. adults used some form of CAM in the past 12 months. Subgroup differences were noted in the use of CAM: women were more likely than men to use CAM; black adults were more likely than white adults or Asian adults to use CAM when megavitamin therapy and prayer specifically for health reasons were included in the definition; persons with higher educational attainment were more likely than persons with lower attainment levels to use CAM; and those who had been hospitalized in the past year were more likely than those who had not been in the hospital in the past year to use CAM. However, when specific CAM therapies were examined, different patterns of use were noted, indicating the importance of the relationship between respondent characteristics and CAM therapy. The findings that gender, education, and health status are associated with CAM use are consistent with earlier reports (1,2,5,9,11). However, this is the first observation that black adults (71.3%) and Asian adults (61.7%) are substantial users of CAM. Additional surveys are needed to explore use within these minority groups.
The survey also revealed that most people who have ever used CAM have used it within the past 12 months and provided national confirmation of an observation seen in a single State (9). These results are surprising given the lack of definitive evidence supporting the safety and efficacy of most CAM interventions. Research-based information on CAM therapies is available to the public from sources such as the National Library of Medicine’s ‘‘CAM on PubMed’’ and ‘‘Medline Plus’’ or the Cochrane
Collaboration Database (28–30).
The data confirm most earlier observations that most people use CAM to treat and/or prevent musculoskeletal conditions or other conditions associated with chronic or recurring pain (1,5,9,10). The high prevalence of CAM use for these conditions is not surprising when one considers that one-quarter to one-third of the adult population might be suffering from one of these disorders in any given year (31,32), yet many forms of chronic pain are resistant to conventional medical treatment (33,34). The high prevalence of CAM use for colds has not been reported previously for the U.S. adult population (35) and is consistent with the observation that 40.3% of individuals who use natural products use the herbal product echinacea, which is widely used for diseases of the upper respiratory
About 1.0% of adult CAM users utilized CAM to treat each of the following three conditions: high cholesterol (1.1%), asthma (1.1%), and hypertension (1.0%). These results are interesting given that there are many effective ways to manage these conditions using both normal lifestyle changes and conventional pharmaceutical drugs. Further analyses will need to clarify the specific populations with these conditions using CAM, the types of CAM they employ, and the reasons why they use CAM
Compared with earlier surveys, theNHIS CAM supplement has several important characteristics. These include questions about use of an extensive list of CAM therapies, a wide variety of health conditions and diseases for which they may be used, and questions about reasons for use and satisfaction with
treatment. In addition, unlike earlier surveys, the NHIS yielded CAM data that are representative of the adult U.S. population. Also, the NHIS has a large sample size so that subgroups can be examined, and data from the CAM component can be linked to a wide variety of respondent characteristics, enriching the analytic potential.
In the population-based surveys conducted in the United States on CAM use since 1990, CAM has been
operationally defined in a variety of ways (1–11). Most surveys asked participants to indicate whether they used one or more items from a list of CAM interventions/therapies, but the
lists varied considerably among the surveys. The most common CAM interventions/therapies included in the surveys, in order of most common inclusion, were chiropractic care, acupuncture, herbal medicine, hypnosis, massage therapy, relaxation techniques, biofeedback, and homeopathic treatment. CAM interventions/therapies such as chelation therapy, energy therapies, qi gong, tai chi, yoga, high-dose vitamins, and spirituality/prayer for health purposes were less commonly included.
In addition to differences in the definition of CAM, the previous population-based surveys varied from the NHIS survey in several other ways that might affect estimates of CAM use in the adult population. Few of the previous surveys were conducted using extensive, in-person interviews with participants randomly chosen to reflect the U.S. population (2,3,8,10). Instead, most relied on telephone interviews with random-digit dialing used to select households or a mail survey with recipients randomly chosen from an existing database of individuals who had previously agreed to respond to such surveys. Telephone and mail surveys tend to exclude lower income individuals who might not have access to a telephone or a stable mailing address and thus impair the representativeness of the data. Most previous surveys were small, with only two having sample sizes above a few thousand individuals (2,3,8). This
limited the ability to estimate CAM use among minority populations of interest such as adults of Hispanic or Asian heritage. Only six of the previous surveys identified the diseases and/or
conditions associated with CAM use (1,2,4,5,9,10), and only four collected information on participant satisfaction with their CAM treatment (1,6,9,11).
Most of the earlier surveys did notinclude questions about health insurance coverage, and only one included a question about reasons for CAM use (1)
Consistent with previous studies (1,3,5), the present study found that the majority of individuals used CAM in conjunction with conventional medicine (54.9%). About one-quarter of U.S. adults who used CAM during the past 2 months did so because CAM use was suggested by a conventional health care
provider, a rate almost identical to that seen in South Carolina (9). More surprising is the finding that 27.7% of individuals who use CAM believed that conventional medicine would not help
their health care problem. These data are contrary to a previous observation that CAM users are not, in general, dissatisfied with conventional medicine (1).
1. Astin JA. Why patients use alternative medicine: results of a national study. JAMA 279(19):1548– 53. May 20, 1998.
2. Bausell RB, Lee WL, Berman BM. Demographic and health-related correlates to visits to complementary and alternative medical providers. Med Care 39(2):190–6. Feb. 2001.
3. Druss BG, Rosenheck RA. Association between use of unconventional therapies and
conventional medical services. JAMA 282(7):651–6. Aug. 18, 1999.
4. Eisenberg DM, Kessler RC, Foster C, et al. Unconventional medicine in the United States. Prevalence, costs, and patterns of use. N Engl J Med 328(4):246–52. Jan. 28, 1993.
5. Eisenberg DM, Davis RB, Ettner SL, et al. Trends in alternative medicine use in the United States, 1990–1997: results of a follow-up national survey. JAMA 280(18):1569–75. Nov. 11, 1998.
6. Landmark Healthcare, Inc. The Landmark Report on Public Perceptions of Alternative Care. Landmark Healthcare, Inc., Sacramento, CA. 1998.
7. Mackenzie ER, Taylor L, Bloom BS, et al. Ethnic minority use of complementary and alternative medicine (CAM): A national probability survey of CAM utilizers. Alternative Therapies in Health and Medicine 9(4):50–56. 2003.
8. Ni H, Simile C, Hardy AM. Utilization of complementary and alternative medicine by United States
adults: Results from the 1999 National Health Interview Survey. Med Care 40(4):353–8. Apr. 2002.
9. Oldendick R, Coker AL, Wieland D, et al. Population-based survey of complementary and alternative
medicine usage, patient satisfaction, and physician involvement. Southern Medical Journal 93(4):375–81. 2000.
10. Paramore LC. Use of alternative therapies: Estimates from the 1994 Robert Wood Johnson Foundation National Access to Care Survey. J Pain Symptom Manage 13(2):83–9. Feb. 1997.
11. Rafferty AP, McGee HB, Miller CE, Reyes M. Prevalence of complementary and alternative medicine use: State-specific estimates from the 2001 Behavioral RiskFactor Surveillance System. Am J Public Health 92(10):1598–1600. 2002.
12. Center for Medicare and Medicaid Services. 1997 National Health Expenditures Survey. Available at:
13. Engel LW, Straus SE. Development of therapeutics: Opportunities within complementary and alternative medicine. Nat Rev Drug Discov 1(3): 229–37. Mar. 1, 2002.
14. Sparber A, Wootton JC. Surveys of complementary and alternative medicine: Part II use of alternative and complementary cancer therapies. J Altern Complement Med 7(3): 281–7. June 2001.
15. Wootton JC, Sparber A. Surveys of complementary and alternative medicine: Part III use of alternative and complementary therapies for HIV/AIDS. J Altern Complement Med 7(4):371–7. Aug. 2001.
16. NCCAM. Five Year Strategic Plan: 2001–2005. Available at: http://nccam.nih.gov/about/plans/fiveyear/index.htm
17. WHO. Legal status of traditional medicine and complementary/ alternative medicine: A worldwide
review. WHO Geneva. 2001.
18. Watanabe S, Imanishi J, Satoh M, Ozasa K. Unique place of Kampo (Japanese traditional medicine) in
complementary and alternative medicine: A survey of doctors belonging to the regional medical association in Japan. Tohoku J Exp Med 194(1): 55–63. May 2001.
19. Jonas WB, Levin JS (eds.) Essentials of complementary and alternative medicine. Lippincott, Williams & Wilkins. 1999.
20. NIH Consensus Conference Statement, Acupuncture. JAMA 280(17): 1518–24. Review. Nov. 4, 1998.
21. NIH Technology Assessment Conference Statement, Integration of behavioral and relaxation approaches into the treatment of chronic pain and insomnia. NIH Technology
Assessment Panel on Integration of Behavioral and Relaxation Approaches into the Treatment of Chronic Pain and Insomnia. JAMA 276(4): 313–8. July 24–31, 1996.
22. DHHS. FDA Announces Plans to Prohibit Sales of Dietary Supplements Containing Ephedra. Dec. 30, 2003. Available at: http://www.hhs.gov/news/press/2003pres/20031230.html
23. Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: A systematic review. Drugs 61(15): 2163–75. 2001.
24. National Center for Health Statistics. 2002 National Health Interview Survey (NHIS). Public Use Data Release. NHIS Survey Description. ftp://ftp.cdc.gov/pub/ Health_Statistics/NCHS/ Dataset_Documentation/NHIS/2002/ srvydesc.pdf.
25. Research Triangle Institute. SUDAAN (Release 8.0.1) [Computer Software]. Research Triangle Park,
NC: Research Triangle Institute. 2002.
26. Day JC. Population projections of the United States by age, sex, race, and Hispanic origin: 1995 to 2050, U.S. Bureau of the Census, Current population reports, P25-1130, U.S Government Printing Office, Washington. 1996. (http://www.census.gov/prod/1/pop/p25–1130/)
27. Klein RJ, Schoenborn CA. Age adjustment using the 2000 projected U.S. population. Healthy People
Statistical Notes, no.20. Hyattsville, Maryland. National Center for Health Statistics: Jan. 2001.
28. CAM on PubMed. http://www.nlm.nih.gov/nccam/camonpubmed.html
29. MedlinePlus. http://www.nlm.nih.gov/ medlineplus/
30. Cochrane Collaboration Database. http://www.update-software.com/ cochrane/
31. Lipton RB, Stewart WF, Diamond S, et al. Prevalence and burden of migraine in the United States: Data from the American Migraine Study II. Headache 41:646–57. 2002.
32. Yelin E, Herrndorf A, Trupin L, Sonneborn D. A national study of medical care expenditures for
musculoskeletal conditions: the impact of health insurance and managed care. Arthritis and Rheumatology 44(5):1160–69. 2001.
33. Deyo RA, Weinstein JN. Low back pain. N Engl J Med 344(5):363–70. 2001.
34. Turk DC. Clinical effectiveness and cost-effectiveness of treatments for patients with chronic pain. Clin J Pain 18:355–65. 2001.
35. Fendrick AM, Monto AS, Nightengale B, Sarnes M. The economic burden of non-influenzarelated viral respiratory tract infection in the United States. Arch Intern Med 163:487–94. 2003.
36. Office of Management and Budget. Revisions to the standards for the classification of Federal data on race and ethnicity. Federal Register 62 (210):58782–90. 1997.
37. U.S. Census Bureau. http://www.census.gov/population/www/estimates/aboutmetro.html.