Low health literacy affects a surprisingly large share of the population. Only 12% of U.S. adults score at the proficient level for health literacy, meaning nearly 9 in 10 people struggle to some degree with finding, understanding, or using health information. The groups at highest risk include older adults, people with less formal education, non-native English speakers, certain racial and ethnic minorities, and people managing chronic illness. But the risk factors often overlap, compounding the challenge for those who fall into more than one category.
How Common Low Health Literacy Actually Is
National assessments divide U.S. adults into four tiers of health literacy: below basic, basic, intermediate, and proficient. Fourteen percent fall into the below basic category, meaning they can handle only the simplest health-related tasks, like circling the date on an appointment slip. Another 22% land at the basic level. The majority of adults, 53%, have intermediate skills, enough for moderately challenging tasks like reading a prescription label but not enough for complex ones like comparing treatment options using multiple sources. Only 12% reach proficiency.
In practical terms, this means roughly a third of adults have health literacy skills at or below the basic level. These aren’t people who can’t read at all. Many function well in daily life but hit a wall when the material involves medical terminology, insurance forms, dosage calculations, or risk-benefit comparisons.
Older Adults
Age is one of the strongest predictors of low health literacy. Among adults 65 and older, just 3% score at the proficient level. Several age-related changes drive this pattern. Cognitive decline, even mild forms, can make it harder to absorb new information or recall instructions after a medical visit. Physical changes matter too: hearing loss can make it difficult to follow a doctor’s verbal explanation, and vision loss can turn a medication guide into an unreadable blur.
The relationship runs in both directions. Lower health literacy makes it harder to know when to seek medical attention, how to follow treatment plans, and how to manage chronic conditions. That, in turn, can accelerate physical and cognitive decline. Research on this cycle suggests there may be a threshold effect: once cognitive function dips below a certain point, health literacy drops sharply rather than declining gradually. People in the two lowest literacy categories also tend to report poorer mental health compared to those in the highest category.
Education Level
Formal education is closely tied to health literacy, though the two aren’t identical. A large study using data from over 5,000 adults found a steep gradient. Among people with only a primary-level education, 51% scored at the very poorest health literacy level, and just 6% reached adequate skills. For people who completed a college or university degree, those numbers essentially reversed: only 2% scored at the lowest level, while 59% had adequate skills and nearly 9% scored as strong.
People with an upper secondary education (roughly a high school diploma) landed in the middle but still averaged in the “poor” health literacy range. The skill level considered adequate, meaning you can handle the health information demands of everyday life, roughly corresponds to what’s expected for successful high school completion and college entry. That means anyone who left school before finishing high school faces a particularly steep disadvantage when navigating the healthcare system.
Non-Native English Speakers
About 8.4% of U.S. households speak English less than “very well,” with Spanish speakers making up the largest group. Limited English proficiency doesn’t automatically mean low health literacy in someone’s native language, but in a healthcare system that operates overwhelmingly in English, the practical effect is similar.
The consequences are measurable. People with limited English proficiency report communication problems in healthcare settings at roughly five times the rate of English-proficient patients (42% vs. 7%). After being discharged from a hospital, they’re less likely to understand their diagnosis, less aware of what their medications are for, and less informed about their rights around consent. Medical errors affecting this group are also more likely to cause physical harm compared to errors affecting English-proficient patients. Interpreter services help significantly, improving understanding of both treatment plans and informed consent, but they aren’t always available.
One study found that limited English proficiency alone wasn’t enough to significantly reduce cancer screening rates. But when limited English proficiency combined with low health literacy, people were less likely to get recommended breast cancer and colorectal cancer screenings. The two risk factors together are more dangerous than either one alone.
Racial and Ethnic Minorities
Racial disparities in health literacy are stark. Among non-Hispanic Black adults, 24% have below basic health literacy, compared to 9% of non-Hispanic white adults. Hispanic adults also face disproportionately high rates, driven partly by language barriers and partly by the same socioeconomic factors that affect health literacy across all groups: lower average educational attainment, reduced access to healthcare, and fewer opportunities to build health knowledge over time.
These gaps aren’t just about individual skills. Healthy People 2030, the federal government’s public health framework, now distinguishes between personal health literacy (an individual’s ability to find and use health information) and organizational health literacy (how well healthcare systems make their information accessible). When hospitals use complex paperwork, clinics don’t offer multilingual materials, or providers speak in jargon, the system itself creates barriers that fall hardest on communities already at higher risk.
People Managing Chronic Conditions
Chronic diseases like diabetes, hypertension, heart disease, and arthritis are both a cause and consequence of low health literacy. Managing these conditions requires reading food labels, tracking blood sugar or blood pressure, understanding when to adjust behavior, and following multi-step medication regimens. When health literacy is low, each of those tasks becomes a potential point of failure.
The clinical impact is real. Among people with heart failure, those with low literacy skills had a 46% higher rate of heart failure-related hospitalization and a 31% higher rate of hospitalization or death from any cause, even after accounting for differences in demographics, clinical severity, and self-management habits. Cross-sectional studies from the U.S. and several other countries consistently find that limited health literacy predicts higher rates of hypertension and arthritis specifically.
People With Limited Digital Access
As healthcare moves online through patient portals, telehealth visits, and digital prescription management, a newer risk factor has emerged: low digital health literacy. People with higher health literacy scores and greater access to devices are more likely to seek health information online. Those who prefer non-internet sources like printed brochures or direct conversations with a provider tend to be over 65, Hispanic, or have less than a high school education, mirroring the same at-risk groups for traditional health literacy.
Digital tools also introduce new sources of confusion. In one study, some Spanish-speaking participants who heard the term “fitness tracker” worried the device could be used to track their physical location. Language and cultural context shape how people interpret health technology, not just whether they can operate it. Interestingly, older adults with low digital health literacy were more likely to trust online health information compared to younger adults with similar skill levels, raising the risk of acting on inaccurate or misleading content.
The Financial Cost of the Gap
Low health literacy costs the U.S. healthcare system an estimated $105 billion to $238 billion per year in direct costs. For individual patients, limited health literacy adds anywhere from $143 to nearly $7,800 in additional healthcare spending compared to patients with adequate skills. When indirect costs are factored in, including the health consequences of poor nutrition, lack of exercise, and continued smoking that stem partly from limited health understanding, estimates reach as high as $1.6 to $3.6 trillion annually.
These costs come from avoidable emergency room visits, preventable hospitalizations, medication errors, and missed preventive care. People with low health literacy are less likely to use preventive services, more likely to be hospitalized, and more likely to struggle with managing conditions that, with the right understanding, could be controlled at home.