The association between education and health outcomes has been well documented, and education has historically been used as an indicator for socioeconomic status in epidemiological studies (Pamuk et al. 1998). Researchers hypothesize that education may protect against disease by influencing lifestyle behaviors, problem-solving abilities, and values. Other researchers have demonstrated a strong association between education and health by exploring three explanations for this association: (1) education influences work and economic conditions; (2) education influences social psychological resources; and (3) education supports a healthy lifestyle (Nielsen-Bohlman et al. 2004). Although the demonstrated evidence of the association between health and education is strong, the explanations for this association and the underlying mechanisms have not been extensively studied. In the past decade, researchers, mainly rooted in the US, have begun to unpack education in an effort to investigate the factors that may more precisely predict poorer health outcomes and help to explain aspects of disparity. Literacy, specifically health literacy, emerged as a distinct area of research and construct to be examined as one possible pathway for the link between education and health.
In the report “Healthy people 2010,” the US Department of Health and Human Services (2000) defined health literacy as the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions. Health literacy focuses on the interaction between individual level skills and structural factors such as health sector demands. The need for a health-literate public has become more critical than ever because of rapid innovations in biomedical sciences and the proliferation of information in a variety of media and the movement toward informed and shared decision-making that promotes involvement of the patients in medical decisions (Rimer et al. 2004; Viswanath 2005).
At the individual level, variables such as background knowledge, experience, emotional state, efficacy, and literacy skills affect one’s overall health literacy. Most of the attention and research to date has been on functional literacy skills required for tasks needed in the workplace and for full participation in the activities of everyday civic life, including interacting with health-care systems. The National Adult Literacy Survey (NALS) in the US and the International Adult Literacy Surveys (IALS) in 22 industrialized nations involved home-based interviews with 13,000 adults in the US and over 75,000 adults from other industrialized countries (Kirsch et al. 1993; Tuijnman 2000). The surveys examined adults’ functional literacy skills – their ability to use the written word for mundane tasks such as locating information in a newspaper or in a form. The tasks that adults were asked to perform ranged from fairly simple (locate a piece of information in a text) to sophisticated (determine the amount of medicine to be given to a child of a specified age and weight based on a medicine label). The scores were reported for three different literacy scales: prose literacy, the knowledge and skills needed to understand and use information from texts that include editorials, news stories, poems, and fiction; document literacy, the knowledge and skills required to locate and use information contained in materials that include job applications, payroll forms, transportation schedules, maps, tables, and graphs; and quantitative literacy, the knowledge and skills required to apply arithmetic operations, either alone or sequentially, using numbers embedded in printed materials.
The findings from the 1992 NALS indicate that fully 47 to 51 percent of US adults have limited or low functional literacy skills and often cannot accurately and consistently locate and match information from newspapers, advertisements, or forms. This does not mean that they cannot read. Most of these adults can and do read.
In 2003, the National Assessment of Adult Literacy (NAALS) was conducted as a follow-up to the 1992 NALS in the United States. Although the educational attainment of US adults had increased between 1992 and 2003, prose literacy had decreased for all levels of educational attainment. As was true in 1992, literacy was lowest for adults who did not complete high school (Kutner et al. 2005).
In one of the earliest attempts to examine health-related literacy tasks (HALS), researchers identified 191 health-related tasks among the NALS and IALS survey data and analyzed the health literacy of US adults. (Rudd et al. 2004). They found that some 12 percent (23 million of US adults) are estimated to have skills in the lowest level (Level 1) on the HALS, while an additional 7 percent (13.4 million) are not able to perform even simple health literacy tasks such as locate dosage information on a medicine label. Those performing below Level 1 are about evenly divided between US-born and foreign-born adults. The results are alarming for at-risk and vulnerable populations; for example, among adults who have not completed high school, almost half scored at or below the lowest literacy level. Similarly, almost half of adults over the age of 65 performed at or below the lowest level. Minority populations, including adults born outside the United States, scored significantly below white adults and adults born in the United States, on average.
Research On Literacy And Health
In a critical examination of the link between literacy and health outcomes, it was found that the health of children in developing countries was related to the literacy of their mothers (Grosse and Auffrey 1989). Subsequent empirical research in the area of health literacy has been conducted mostly in the US and has documented the mismatch between the literacy demands of health systems and the literacy skills of the people using the system. For example, a variety of health-related print materials have been assessed over the years, and researchers report that an overwhelming majority of the materials score at reading grade levels that far exceed the reading ability of the average adult (which is equivalent to the fifth or sixth grade level). International assessments of health materials, focused mainly on informed consent documents, echo these findings (Mathew & McGrath 2002).
Researchers were able to move beyond assessment of materials to better define the association between literacy and health outcomes with the development of health-specific reading assessment tools such as the Rapid Estimate of Adult Literacy in Medicine (REALM) and the Test of Functional Health Literacy in Adults (TOFHLA; Davis et al. 1991; Parker et al. 1995). These tools enabled researchers to assess patients’ health-related reading skills and then correlate the readability/literacy levels with health outcomes in a clinical setting. This body of literature found that patients with low health literacy, defined as individuals with skills below the ninth grade level, are less likely to make use of health-care services such as screening (Davis et al. 1998), more likely to present in later stages of disease (Bennett et al. 1998), and more likely to be hospitalized (Baker et al. 1998), after adjusting for factors such as age, race, gender, socio-economic status, and self-rated health status. In addition, studies indicate that patients with limited health literacy skills who need to manage a chronic disease such as cancer (Merriman et al. 2002; Schillinger et al. 2002; Williams et al. 1998b) or asthma (Williams et al. 1998a) are less well-informed about the basic elements of their care plan and have measurable poorer health outcomes than those patients suffering from the same disease conditions but who possess higher levels of health literacy.
In addition to the ill effects on the individual patient, limited health literacy places a burden on health-care systems which in turn impacts the overall economic consequences to society. In the US, the National Academy on an Aging Society estimated that roughly US$73 billion in additional health-care costs were attributable to low health literacy. This is due in part to higher rates of hospitalization and higher use of expensive emergency services.
As the field of health literacy evolves more research is required to rigorously examine the full breadth of the construct as illustrated in its definition: the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions. This definition goes beyond one’s ability to read and identify health terms; it speaks more to one’s ability to access health information, effectively navigate the information to retrieve relevant information, and then ultimately act on this information. To advance the field of health literacy, researchers must therefore go beyond the examination of reading skills and systematically assess and test interventions that address the other necessary skills, such as obtaining and using information as embedded in the health literacy definition. Health-care providers, creators of health information and education materials, and the health-care and public health systems bear a large part of the responsibility for having created materials, ways of communicating, and systems that are far too technical and complicated to meet the needs of the vast majority of the populations they serve.
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- Tuijnman, A. (2000). International adult literacy survey: Benchmarking adult literacy in North America: An international comparative study. Ottawa: Statistics Canada.
- US Department of Health and Human Services (2000). Healthy people 2010. At www.healthypeople.gov/Document/tableofcontents.htm#under, accessed September 7, 2007.
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- Williams, M. V., Baker, D. W., Honig, E. G., Lee, T. M., & Nowlan, A. (1998a). Inadequate literacy is a barrier to asthma knowledge and self-care. Chest, 114(4), 1008 –1015.
- Williams, M. V., Baker, D. W., Parker, R. M., & Nurss, J. R. (1998b). Relationship of functional health literacy to patients’ knowledge of their chronic disease. A study of patients with hypertension and diabetes. Archives of Internal Medicine, 158(2), 166 –172.