The concept of health literacy (HL) is constantly evolving. The Healthy People 2030 initiative defines HL as “the degree to which individuals have the ability to find, understand and use information and services to inform health-related decisions and actions for themselves and others.” [1]. It refers to individuals’ using their cognitive and social skills for gaining access to, understanding, and using information for promoting and maintaining good health for themselves and for others around them [2]. According to the United Nations Educational, Scientific and Cultural Institution, about 388 million adults in South and Southwest Asian countries continue to grapple with illiteracy, coupled with a lack of basic HL [3]. Even though many high-income nations, such as the United States, Canada, the United Kingdom, and Australia, have included HL in their national agenda [4], more than one-third of individuals in the United States still have limited HL, which consequently results in misunderstanding of medical information, increased health care–related costs, and poor health outcomes [5,6]. Individuals who face difficulty in understanding health-related materials may experience shame and discomfort in interacting or sharing their medical concerns and questions with health professionals [7].

HL functions as a critical component within the context of other social determinants of health (SDoH), such as education, socioeconomic status, access to quality health care, neighborhood and built environments, and social support networks [8,9]. Low literacy levels impact an individual’s ability to access and use health care services by making it challenging for them to navigate health systems, understand health insurance information, and adhere to treatment plans resulting in delayed or inadequate care [10,11]. Individuals with a low socioeconomic status often have low HL levels, leading to difficulties in understanding providers’ instructions, managing illness, and making informed health care choices for themselves [12]. Although studies indicate education may be associated with HL, the data cannot speak to a direct cause and effect tying higher education levels to higher HL [13]. Education is not a reliable proxy for determining literacy, as individuals with higher education may still have difficulty in understanding information pertaining to their health or the health of their families.

HL plays an important role in reducing health disparities, empowering individuals, and improving patient-provider communication and health outcomes. Individuals who possess high levels of HL are in a better position to understand medical instructions provided by their doctors, actively participate in decisions related to their health, and navigate the complex health care system. Changes within the health care environment, specifically the increased use of digital communication platforms, have transformed health care delivery and highlighted additional concerns around optimal patient-provider engagement. Digital health literacy (DHL) has become a significant component of HL with the increasing use of digital technologies in health care, including telehealth platforms, wearable devices, and mobile health apps and websites [14]. Although DHL shares core conceptual elements of HL, it differs as it requires an individual to possess additional skills to use technological devices, such as mobile phones and computers, and skills to use those devices to search and evaluate health-related information available online through multiple sources [14]. It is therefore essential for individuals to possess DHL skills to navigate digital technologies, access accurate and reliable online health information, and engage with telehealth platforms.

Despite the recognition of HL and DHL as essential factors of health care quality and outcomes, challenges exist in achieving optimal levels of literacy skills nationally and internationally [15]. Additionally, the increasing focus on DHL interventions poses new challenges in improving DHL, such as possessing skills to use new digital health technologies and identifying credible sources of information online [16]. Furthermore, a 1-size-fits-all approach for HL and DHL fails to account for cultural and linguistic diversity, age and generational differences, multiple health conditions and contexts, unequal access to digital resources, and diverse HL levels [17]. To develop a deeper understanding of the current state of HL and DHL research, we reported the results of a survey of HL and DHL researchers in this study. The aim was to comprehensively examine researchers’ conceptualization of and approaches to HL and DHL work, identify strategies, and highlight areas for further investigation and intervention. This research addressed the following research questions:

We used an iterative approach to develop the survey as per CHERRIES (Checklist for Reporting Results of Internet E-Surveys) [18]. Two team members drafted the initial list of questions, and all team members, including experts in HL and DHL, weighed in on multiple drafts. To ensure the survey’s reliability, we consulted content experts to design survey questions and response options that were appropriately worded and meaningful to study participants. Since we did not aim to measure any specific constructs, we did not conduct the type of survey validation that we would have done otherwise. Survey questions examined researchers’ specific focus (HL, DHL, or both); funding sources for HL and DHL research; and definitions, conceptual frameworks, and approaches used to study HL and DHL. We were also interested in understanding whether respondents studied HL/DHL in combination with other SDoH, as well as the research settings and geographic locations of their research. We asked about their main discipline/affiliation, number of years studying HL or DHL, educational qualification, and place of employment. Finally, we inquired about the data collection methods used in their research, whether they had ever received mentorship in HL/DHL work, or whether they provided mentorship to others. Respondents could select more than 1 response option for several of the survey questions.

This study was considered exempt by the University of South Carolina (USC) Office of Research Compliance under approval number Pro00124306.

We applied a search string (“literacy” or “health literacy” or “digital health literacy” or “e literacy” or “e health” or “m health” or “e health literacy”) to project titles, project terms, and project abstracts on the grantee website of the National Institutes of Health (NIH) RePORTER (RePORT Expenditures and Results) and the Canadian Institutes of Health Research in November 2022. Project investigators (PIs) of studies matching those parameters were included in the sample. We obtained the email addresses of the PIs directly from the NIH RePORTER website and manually searched for email addresses of the PIs selected from the Canadian Institutes of Health Research grantee website. We excluded PIs for whom email addresses were unavailable on the NIH RePORTER grantee website, as well as PIs from the Canadian Institutes of Health Research whose email addresses could not be located through manual searches. The final sample included 2042 individual investigators. We also distributed the survey link via 2 organizational listservs consisting of members focused on health communication and health promotion research and practice.

We programmed the survey questions in Qualtrics [19]. Next, we prepared separate email lists for NIH and Canadian Institutes of Health Research PIs in Qualtrics, and invitations to participate in the survey were sent on January 23, 2023. The invitation email included a brief description and purpose of the study and a link to the Qualtrics survey and informed participants that survey completion would take approximately 15-20 minutes. Five email reminders were sent from Qualtrics at regular intervals to encourage participation and completion of the survey before its scheduled closure on April 23, 2023. All survey respondents were entered into a random drawing for 1 of 5 US $25 Amazon gift cards.

Data were downloaded into Microsoft Excel. IBM SPSS Statistics version 28 [20] was used to conduct descriptive analysis including frequencies and percentages, and chi-square tests with a significance level of P<.05 were performed to explore the association between respondents’ research focus (HL, DHL, both) and the settings and age groups with whom they conducted their research. We included responses from all 193 respondents and did not eliminate surveys that had missing responses. Analysis was conducted in a way that the results for each survey question contained only the valid responses for that question with the relevant denominator.

A total of 193 respondents answered the survey questions. Almost half (76/153, 49.7%) reported public health as their main discipline, 41/153 (26.8%) reported medicine, 38/153 (24.8%) reported health services/policy, 21/153 (13.7%) were from education, and 17/153 (11.1%) identified nursing as their academic discipline. Most had a PhD (98/132, 74.2%), 16/132 (12.1%) were MDs, and 13/132 (9.8%) had a master’s degree as their highest educational qualification. Employment settings ranged from university (93/132, 70.5%), hospital system (12/132, 9.1%), or research institution (10/132, 7.6%). Most (106/132, 80.3%) of the respondents had never received any formal mentorship in HL or DHL. Those who had received formal mentorship reported receiving training from an academic mentor, professional organization seminars, or professional training. Just over half (73/142, 51.4%) reported that they had been studying HL or DHL for 1-5 years, and 37/142 (26.1%) indicated more than 10 years of experience studying HL or DHL.

Regarding the scope of work, 83 (43%) of 193 respondents reported that most of their work focused on HL, while 46 (23.8%) reported DHL, and the remaining 64 (33.2%) indicated a dual focus including both HL and DHL. When asked about the specific topics of focus, 87/139 (62.6%) respondents reported that they had a general focus on HL/health communication, 61/139 (43.9%) focused on topics around social justice/health equity, 48/139 (34.5%) focused on face-to-face patient-provider communication, 41/139 (29.5%) focused on misinformation/disinformation, 37/139 (26.6%) focused on virtual patient-provider communication, 36/139 (25.9%) focused on peer-to-peer health conversations, and 27/139 (19.4%) focused on policy development. Respondents had almost equal focus on specific health behaviors, including healthful eating (36/139, 25.9%), physical activity (36/139, 25.9%), and cancer screening (33/139, 23.7%).

About two-thirds (100/156, 64.1%) of the respondents reported not using any specific definition of HL or DHL to guide their work. Of those who did follow a specific definition (n=56, 35.9%), roughly 19 (33.9%) indicated using the Institute of Medicine’s [21] definition. Other definitions cited were by Nutbeam [22], the World Health Organization [23], U.S. Department of Health and Human Services [1,24], among others, as described in Table 1. Research by about one-third (46/143, 32.2%) of the respondents was guided by the Healthy People 2030 framework [1]; 35/143 (24.5%) used the Nutbeam framework that describes HL as functional, interactive, and critical [22]; 27/143 (18.9%) used the HL skills framework by Squiers et al [25]; and 18/143 (12.6%) used the HL systems capacity framework by Sorenson et al [26]. Regarding DHL research, 17/143 (11.9%) respondents used the electronic health literacy (eHL) framework by Bautista [27], 12/143 (8.4%) used the eHL definition and the Lily model by Norman and Skinner [14], 12/143 (8.4%) used the eHL framework by Norgaard et al [28], and 10/143 (7%) used the consumer eHL taxonomy by Chan et al [29]. Some respondents (6/143, 4.2%) did not follow any framework, whereas others mentioned they used dissemination and implementation science–based, collaborator-informed socioecological models and environmental HL frameworks. Frameworks used in HL and DHL research are presented in Table 2.

Table 3 presents the settings in which respondents conducted their research. Most conducted their HL/DHL work in a community setting (106/135, 78.5%); 49/135 (36.3%) reported a primary care setting; 44/135 (32.6%) reported a specialty care setting; 29/135 (21.5%) reported the virtual health care space, such as patient portals/provider portals; and 20/135 (14.8%) reported government-/policy-level settings. Chi-square tests indicated that of those (n=20, 14.8%) who conducted research in a government-/policy-level setting, 14 (70%) were focused on HL research, while 13 (44.8%) of the respondents who conducted research in the virtual health care space were focused on DHL. Only significant (P<.05) chi-square test results are presented in Table 4. When asked about the specific approaches that they used in their work, 89 (65.9%) respondents mentioned using digital tools, such as apps, websites, patient portals, virtual visits, and wearable devices; 82/135 (60.7%) reported using plain-language materials; 56/135 (41.5%) used visual guides, such as graphical decision tools; 39/135 (28.9%) used teach-back strategies; and 36/135 (26.7%) made use of a partnership with patient navigators. Most respondents used mixed methods (109/134, 81.3%) for their work. For data collection, 112/134 (83.6%) respondents reported that they collected data using interviews, 118/134 (88.1%) conducted surveys, 89/134 (66.4%) conducted focus groups, 50/134 (37.3%) conducted secondary data analysis, and 44/134 (32.8%) completed scoping and systematic reviews and meta-analysis. Other types of data collection methods included content analysis (33/134, 24.6%), comprehension testing (23/134, 17.2%), readability testing (25/134, 18.7%), and observational data (42/134, 31.3%).

Most respondents (133/153, 86.9%) reported that they studied HL/DHL in combination with other SDoH. Health care access and quality were studied with HL/DHL most often (93/133, 69.9%), followed by social and community contexts (80/133, 60.2%), education access and quality (57/133, 42.9%), neighborhood and built environment (44/133, 33.1%), and economic stability (40/133, 30.1%). Other SDoH, as reported by respondents, included equity, gender and caregiving support, insurance and employment status, language equity, mental health stigma, poverty, culture, environmental exposures, and other measures of socioeconomic status.

Respondents conducted research mostly with adult populations (131/139, 94.2%), 42/139 (30.2%) conducted research with adolescents (12-17 years old), and 23/139 (16.5%) conducted research with youth (<12 years old). There were no significant chi-square test results between the focus of research and the age categories of respondents’ research participants. Some respondents reported conducting research with all/diverse races (47/121, 38.8%), while others indicated a more limited approach. One-third (40/121, 33.1%) respondents conducted research with only Black, African American, or both populations; 31/121 (25.6%) reported research with White/Caucasian/European Americans; 32/121 (26.4%) reported research with Hispanic or LatinX populations; and 11/121 (9.1%) reported research with Asian, South Asian, and East Asian populations. Most respondents (83/137, 60.6%) reported that they conducted research with the general public, 43/137 (31.4%) reported research with general patients, and 58/137 (42.3%) reported research with patients of a specific health/medical specialty. About one-third (44/137, 32.1%) of the respondents conducted research with general clinical providers; 43/137 (31.4%) included physicians, nurse practitioners, and PAs as their research participants; and 27/137 (19.7%) worked with professionals who were from nursing and related clinical/health sciences backgrounds. Respondents also conducted research with specific communities who had a specific culture (33/137, 24.1%); the lesbian, gay, bisexual, transgender, queer, questioning, intersex, asexual, and other (LGBTQIA+) community (15/137, 10.9%); individuals without a shelter or stable housing (15/137, 10.9%); and individuals with disabilities (10/137, 7.3%).

This study was a comprehensive examination of researchers’ conceptualization of and strategies for conducting HL and DHL research. Understanding principles and methods that guide the work in this area is critical for advancing the field, pursuing needed interventions in both clinical and community settings, and studying literacy in the context of additional social determinants that influence health behaviors and outcomes.

Approximately three-quarters of the respondents reported public health and medicine as their academic and professional disciplines. Although the nursing profession is proportionately greater than the discipline of public health or medicine, only 11% of the respondents conducting HL research had a nursing background. Worldwide, nurses serve as critical partners in the health care encounter as they provide education and facilitate communication exchange, which can aid patient HL [64]. However, research demonstrates that nurses in the United States cannot identify patient communication behaviors that point toward low HL levels [65]. Engaging nursing professionals in HL and DHL research is important because nurses interact directly with patients, which makes them well positioned to develop and implement strategies to fully understand the needs and challenges of a diverse patient population. More involvement of nursing professionals would help in developing informed and tailored communication strategies for patient populations and help determine the most effective ways for communicating health information with patients of varying levels of literacy. HL research by nursing professionals would help in reducing disparities as understanding the challenges by patients from diverse backgrounds would allow nursing professionals to deliver more equitable health care.

Our survey was distributed primarily via lists of researchers who had NIH funding in the United States or funding through the Canadian Institutes of Health Research; thus, our sample primarily reflects researchers who have been awarded through these funding streams. There are likely others in the field who have carried out their work using other funding streams. Since research agendas are, to some extent, directed by the priorities of funding agencies, this survey may have missed individuals conducting different kinds of HL work. Additionally, since we primarily searched the grantee websites of the NIH and the Canadian Institutes of Health Research, our sample of researchers was primarily based in high-income countries. As we could not reach out to researchers in low- and middle-income countries, our study findings cannot be generalized to other countries. Despite keeping the survey open for a period of 3 months and sending 5 reminder emails for completing the survey, the low response rate of our survey further restricts the generalizability of our study findings. As we did not conduct cognitive testing of our survey questions, there is a possibility that our questions did not address the most meaningful information. Finally, the majority of our questions were closed ended, which may fail to capture the complexity of the working definitions used by respondents, as well as the variety of work they engage in. Even though this study has limitations, we strongly believe that the study findings still provide important insights into the scope of and how researchers conceptualize HL and DHL research, which can inform future research directions. Understanding what funded researchers are doing in this area of research and with the growth in the need for research on SDoH, this study can help inform more comprehensive examination of this field of research.

The results of our survey indicate there is significant variation in how HL is researched and understood. Although a variety of approaches may add richness to the field, it also makes comparisons across studies and generalizability of findings more difficult. Further, few respondents reported receiving any formal mentorship in their study of HL or DHL, which may perpetuate inconsistencies in how HL is defined, since knowledge transfer from one generation of researchers to another may be limited. It is encouraging that the majority of survey respondents investigated HL along with other SDoH, given the inequality that is often pervasive within health systems and the importance of going beyond studies of readability to more contextual factors. However, the lack of work in the clinical setting is problematic, since it has been recognized that HL is a structural issue that the health sector must address. Given the somewhat limited consistency in how the concept is currently defined and the evolution of the field from the study of readability of documents to the exploration of literacy within the context of social factors and health equity, opportunities exist to leverage conferences, scientific meetings, and other professional spaces to learn from each other and create mentorship opportunities for junior scholars and those who may be moving into this area. This would facilitate continued discussion among practitioners and researchers to create common definitions and goals around HL, DHL, and their relationship to SDoH.