Lack of knowledge was found to affect utilization of common complementary health practices, regardless of the potentially motivating presence of back pain. Disparities in the utilization of complementary medicine, related to educational attainment and other socioeconomic factors, may negatively affect quality of care for many Americans. Creative approaches are needed to help reduce inequities in understanding and improve access to care for underserved populations.

A hypothesized association between lack of health knowledge, lower educational attainment, and other key socioeconomic indicators was supported in the findings. Although it was hypothesized that low back pain would be associated with greater information seeking, regardless of level of education, that hypothesis was not supported.

To explore this issue two samples were created using data from the 2007 National Health Interview Survey Complementary and Alternative Medicine supplement. Of particular interest was the relationship between lack of health knowledge, as a reason for non-use, and key independent variables. The first sample was comprised of individuals who had never used any of four common complementary health practices -- acupuncture, chiropractic, natural products, and yoga. The second was a subset of those same non-users who had also reported low back pain, the most frequently cited health concern related to use of complementary therapies.

Complementary health practices are an important element of health/healthcare seeking behavior among adults in the United States. Reasons for use include medical need, prevention and wellness promotion, and cultural relevance. Survey studies published over the past several decades have provided important information on the use of complementary health practices, such as acupuncture and yoga. A review of the literature, however, reveals an absence of studies looking specifically at who does not use these approaches, and why not.

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Research provides information on the relationship between health knowledge and conventional healthcare utilization. Corresponding information on the relationship between health knowledge and use of complementary healthcare practices, however, is missing. To explore this issue, lack of knowledge of four commonly used complementary health practices was examined, as a reason for their non-use. A hypothesized association between lack of knowledge, lower educational attainment, and other key socioeconomic indicators was supported in the findings. An additional analysis was conducted with a subset of those same non-users who also reported low back pain. Low back pain was chosen as the main health complaint for this analysis for several important reasons. First, back pain is the most prevalent health condition related to use of complementary therapies [ 2 – 3 ]. Research also suggests that individuals with low back pain actively seek out information and treatment options for their condition [ 24 ], which would presumably include information on complementary health practices. Finally, best practice clinical guidelines for the management of back pain include several complementary health practices [ 25 ], and Medicare provides coverage for chiropractic treatment of back pain [ 26 ]. For these reasons it was hypothesized that this subset of respondents with back pain would be more likely to seek information and possess knowledge of CHP options for back pain, regardless of level of educational attainment. This anticipated outcome was not supported in the findings. Taken together these results suggest that factors such as lower educational attainment contribute to disparities in access to potentially useful therapeutic services by virtue of limited health knowledge, even among those with back pain.

Health literacy has been defined as, “The degree to which individuals have the capacity to obtain, process, and understand basic information and services needed to make appropriate decisions regarding their health" [ 11 ]. Conceptual knowledge of health and healthcare is an important element of health literacy, such as knowledge of treatment options [ 11 – 12 ]. Limited health knowledge and health literacy can significantly affect utilization of conventional healthcare services, the practice of preventive health behaviors, disease management, disease outcomes, and healthcare expenditures [ 13 – 17 ]. Correlates of limited health knowledge included lower levels of functional health literacy [ 18 – 19 ], lower educational attainment [ 20 ], lower socioeconomic status, and race [ 21 – 23 ].

Despite all of this research, a review of the literature reveals an absence of studies looking specifically at who does not use CHP’s and why not. With rare exception, such as one study looking specifically at non-use of acupuncture [ 10 ], there have been virtually no detailed analyses of reasons for non-use. To explore this issue a retrospective cross-sectional analysis of the 2007 National Health Interview Survey (NHIS) Complementary and Alternative Medicine Supplement was performed. Of particular interest was respondent self-reported lack of knowledge (of four common complementary practices) as a reason for non-use, suggesting lower health knowledge and health literacy.

Complementary health practices (CHP), such as acupuncture and yoga, are important elements of health/healthcare seeking behavior among adults in the United States. Reasons for use include medical need, prevention and wellness promotion, and cultural relevance [ 1 ]. In terms of medical need, CHP use has been found to be associated with having one or more medical conditions, with having a diagnosed chronic disease, such as low back pain, and with having been hospitalized during the past year [ 2 – 4 ]. In addition to medical need, numerous studies have also found a relationship between use of CHP's and the practice of other conventional preventive health behaviors. CHP users have been shown to be more likely to engage in leisure time physical activity, to be former smokers, to consume alcohol moderately, have a healthier body mass index, eat a lower fat diet, and utilize preventive medical services, such as cholesterol screening [ 5 – 8 ]. Other important insights into the characteristics of individuals who use CHP's include being more prevalent among women, individuals aged 30–69, living in the West, having higher levels of education, and not being poor [ 2 , 3 , 9 ].

Materials and Methods

Data Source The National Health Interview Survey (NHIS) is an annual survey of the health of the United States civilian, non-institutionalized population. It is conducted by the National Center for Health Statistics, Centers for Disease Control and Prevention (CDC). It uses an in-person, computer-assisted interviewing method of administration. The survey contains four main modules: Household, Family, Sample Child, and Sample Adult. The first two modules collect health and socio-demographic information on each member of all families residing within a sampled household. Within each family, additional information is collected from one randomly selected adult (the “sample adult”) aged 18 years or over. The survey uses a multi-stage clustered sample design, and oversamples black, Asian and Hispanic populations to allow for more precise estimation of health characteristics in these growing minority populations. The 2007 NHIS was approved by the National Center for Health Statistics Research Ethics Review Board on October 18, 2006. Verbal consent was allowed by the NCHS Ethics Review Board and was obtained by Census Bureau interviewers from all survey respondents prior to the start of the interview. Public use data files are available online (http://www.cdc.gov/NCHS/nhis/nhis_2007_data_release.htm).

Dependent Variables In the 2007 NHIS supplement, respondents who did not use one or more of the common complementary practices were given ten response options to select from to ascertain their reasons for non-use. The response option “Never heard of it/Do not know much about it” (24% of respondents) was selected as the primary dependent variable for analysis. This reason was selected in order to specifically explore the relationship between health knowledge (of complementary health practices) and non-use. For the rest of the article this variable will be referred to as 'lack of knowledge'. A second dependent variable, “Do not need it” (43% of respondents), was also selected. For the rest of the article this variable will be referred to as 'lack of need'. These two items were chosen as they were among the most frequently selected, their implied meaning was clearer compared to response options like "Some other reason," and they allowed for a parsimonious examination of the interrelated concepts of knowledge and need (particularly, need based on the presence of back pain and the hypothesized search for therapeutic information/knowledge). Associations between these two dependent variables—lack of knowledge and lack of need (as reasons for non-use)—and key independent variables were examined.

Independent Variables Twenty-four items were selected as independent variables based on known associations with both use of complementary health practices and back pain status [2–3], [7], [27–31]. These items included: Demographics—eight socio-demographic characteristics (gender, age, race, ethnicity, geographic region, education, income [defined in terms of poverty status], and marital status); Health Status—five variables related to the respondent’s health status (self-reported health status [excellent, very good, good, fair, poor], any functional limitation, hospitalization in the previous 12 months, visits to the emergency room (ER) in the previous 12 months, and back pain); Health Behaviors—five health behaviors and risk factors routinely monitored by the CDC [32] (activity level [inactive, some activity, regular activity], smoking status [current, former, never], alcohol consumption [lifetime abstainer, former drinker, current infrequent drinker, current moderate/heavy drinker], body mass index (BMI) [underweight, healthy weight, overweight, obese], and whether the respondent had received a flu vaccination in the past 12 months and/or ever received the pneumonia vaccine; and Healthcare Access—six variables related to conventional healthcare access and use (usual place for sick care, health insurance coverage, number of visits to a conventional provider in the previous 12 months [0–3, 4–9, 10+], delayed healthcare for reasons of cost, delayed healthcare for reasons other than cost, and ability to pay common ancillary healthcare expenses [prescription medication, mental healthcare, dental care, or prescription eyeglasses]). Back pain was included as an independent variable in the full sample. It was also used as the variable for stratification in the creation of a second 'back pain only' subsample. Back pain was selected for a subsample analysis as low back pain and other back problems are cited as the most common reasons for use of complementary therapies [2–3]. In addition, low back pain is prevalent in the general population, is clinically and socially costly, and current best practice guidelines for the management of back pain include non-pharmacological complementary health interventions, such as acupuncture, spinal manipulation, massage and yoga [25]. Back pain status was based on the following question in the 2007 NHIS Adult Core—"During the PAST THREE MONTHS, did you have low back pain?”