The size and cost of the health literacy shortfall
A large share of adults in the United States and Europe have less health literacy than health information assumes, and the shortfall is greatest among older, poorer and less healthy people. Low health literacy goes with worse health, higher mortality, higher health care costs, poorer adherence to treatment and harder decisions.
How many fall short in the United States
In 2003 the National Assessment of Adult Literacy reported separately on health literacy for the first time. It found 36% of the US adult population with basic or below-basic health literacy. Adults at those levels may be able to read short, commonplace prose and understand simple documents, but they lack the skills for more complicated tasks, such as working out from a drug label when to take a prescription medication.
For combined prose and document literacy, the 2003 assessment put approximately 40% of American adults at level 1 and below, the most basic of its five proficiency levels, and a considerably greater percentage of adults older than 65. The assessment's scores have no equivalent in reading grade levels, but level 1 approximately compares with a sixth- to seventh-grade reading level. Its health literacy results for level 1 and below were quite similar. Readers with low skill levels have difficulty understanding many written patient instructions, using the information to carry them out and solving health-related problems. The National Action Plan to Improve Health Literacy states that only individuals with full proficiency can successfully understand and act on all their health care instructions.
Low health literacy is related to general illiteracy, and according to the National Assessment of Adult Literacy 14% of the US population struggles to write, read, listen or speak effectively. In 2003, according to the National Center for Education Statistics, 14.5% of adults lacked basic prose literacy skills.
A 2008 study found that only about one-third of US adults had civic scientific literacy, the understanding of basic science constructs such as DNA and the solar system.
The low literacy problem escalates with age. Nearly half of the older US population has low reading skills, and in one study 81% of patients over 60 years old could not read and understand basic prescription labels and appointments. In 2011, 38% of adults read at or below a seventh-grade reading level, and so did 58% of adults older than 65.
In 2010 only about one in every ten American adults aged 16 to 65 had proficient health literacy, and 88% of adult Americans had less than proficient health literacy. In 2010 health literacy was lacking in about 50% of the US population. In 2011 more than 50% of Americans struggled to understand health information. A study from the United States showed that one in two people have only intermediate skills in health literacy. In 2015 about 77 million people had basic or below-basic health literacy.
How many fall short in Europe
The European Health Literacy Survey (HLS-EU) was conducted during the summer of 2011 in eight European countries: Austria, Bulgaria, Germany, Greece, Ireland, the Netherlands, Poland and Spain. Its questionnaire was designed to measure health literacy, and almost half (47%) of its approximately 8,000 respondents had limited health literacy. Another account of the same survey puts about half (47.6%) of the respondents from the eight countries at poor or inadequate health literacy.
The European Health Literacy Project's 2011 study used the HLS-EU-Q, a multidimensional, comprehensive questionnaire that measures health literacy in the general population and uses a broad definition of health promotion as the World Health Organization describes it in the Ottawa Charter. The study found more than 10% of all respondents, and 1.8% to 26.9% by country, with an inadequate level of health literacy. It included only a few European countries and had a limited sample size. In 2022 few studies had systematically determined the level of health literacy and the factors that determine and affect it. The study's results show that health literacy is a public health challenge in some European countries.
Spain had no data on its population's health literacy before the European Health Literacy Survey. The survey found only about 37% of Spanish respondents with adequate functional health literacy. In 2013 a Spanish health communication specialist concluded from this that researchers, policy makers and healthcare professionals in Spain still had a long way to go.
In 2020, 42% of adults aged 16 to 65 in England were unable to understand or make use of everyday health information.
How countries compare
Data from the 2011–2012 Programme for the International Assessment of Adult Competencies (PIAAC), sponsored by the Organisation for Economic Co-operation and Development and conducted in the United States by the federal Department of Education, showed greater proportions of US adults with low literacy, numeracy and technology skills than adults in other developed countries. On average, US adults who said they were less healthy scored lower on the literacy skills tests than healthier adults. A senior health literacy adviser at the US Centers for Disease Control and Prevention reads this as meaning that those who most need public health and health care information are least able to access it. She also holds that a large proportion of the population does not interact with health care professionals, in large part because lower literacy leads to a limited understanding of how the health care system works.
In 2022 one practitioner held that the pandemic had revealed that most people in the United States do not have a high level of health literacy or numeracy, and that the competency is probably not much better around the world: perhaps better in a few countries, but in general poor. Another held that the pandemic made clear a division of the public between people who can do their own research and understand a concept such as risk or relative risk, and a vast number who have no idea what that means and no way to calculate their own risk.
Achieving adequate levels of health literacy is a global challenge, even in well-resourced communities.
Who falls shortest
In the 2011 European survey, the subgroups with the lowest health literacy were people with poor health status, low socioeconomic status, lower school education and older age. Financial deprivation was the strongest predictor of low health literacy, followed by social status, education and age, whereas gender had a minor effect. In a Canadian health literacy study, the most important predictor of proficient health literacy was daily reading, and the second most important was level of education.
What the shortfall costs in health
Inadequate health literacy is one of the most significant contributors to poor health and health disparities, along with inadequate access to health care. Reports in 2010 indicated a lack of health literacy skills in the United States and internationally that left many individuals vulnerable to poor health outcomes. Studies show that people with low health literacy skills have worse health outcomes, greater likelihood and severity of disease, less knowledge about health care services, and use fewer preventive measures such as screening. Their mortality is also higher. Individuals with chronic diseases such as diabetes, high blood pressure and heart disease who also have low health literacy have less understanding about their disease and experience more negative outcomes than individuals with higher health literacy.
Health literacy is a stronger predictor of health outcomes than age, income, employment status, education level or race. Low health literacy is associated with poorer health outcomes, including increased rates of hospitalisation and mortality. The mortality rate attributable to low education is comparable to the mortality rate for smoking tobacco, and educational disparities widen with each successive generation.
By 2011 there were more than 1,000 health literacy studies. The Agency for Healthcare Research and Quality reviewed hundreds of them and found low health literacy associated with more hospitalisations and emergency department visits, with problems taking medications, and, among older individuals, with poorer health and higher death rates.
What the shortfall costs in money
Health care costs have been shown to be more than four times higher for individuals with low health literacy than for those with high health literacy. Difficulties such as being unable to read prescription labels can result in costly medication mistakes. One estimate puts the cost of low health literacy to the US economy at up to $238 billion a year. Another puts it at $106 billion to $236 billion a year. In one practitioner's view, health literacy skills are necessary both for an improved quality of life and for containing health costs in the United States. Effective health literacy and communication are critical to good health outcomes and lower health care costs.
What the shortfall costs in adherence and treatment
People with low health literacy make more errors with medications, are less likely to complete treatments, and are more likely to use healthcare services such as hospitalisation, which may even mean a longer stay. Lack of adherence to treatment costs healthcare systems in the EU approximately €1.25 billion a year and is responsible for 194,500 deaths a year there. Adherence to treatment is influenced by health literacy, which suggests that addressing health literacy can positively influence adherence.
What the shortfall costs in understanding and decisions
General understanding of medical and clinical research information is inadequate, which is explained at least in part by the complexity of the information coupled with low health literacy levels. Patients with breast cancer often have to decide between numerous treatment options and clinical trials, and these decisions may be even more challenging when they have limited health literacy. In a study of women with breast cancer invited to enrol in a clinical trial, those who were more confident in their decision to enrol perceived a lack of risks associated with the experimental treatment option. Those who recalled recurrence as a risk of enrolling had an average health literacy score higher than the overall cohort. Participants who understood the risk of recurrence and its weight in the decision also had a better understanding of informed consent. Understanding of informed consent seemed to be related to the level of health literacy, which suggests that improving health literacy can help improve patients' awareness when deciding whether to enrol in a clinical trial.
An Italian study of misinformation about COVID-19 covered eight topics: plot, origin, vitamin C, vitamin D, garlic, 5G, laboratory and HIV. Fake news accounted for 77.8% of all the articles it reviewed, indicating that fake news about COVID-19 was more likely to be viewed and shared than real news. Health literacy directly influences the sharing of news and information by allowing individuals to filter large amounts of information and discern what is fake. Key factors in this include cognitive biases such as confirmation bias and cherry-picking, the willingness to fact-check, digital literacy and the extent of health literacy. Improved health literacy may lead to better understanding of scientific information and the ability to distinguish between real and fake news.