Understanding health literacy within the nexus of environmental, planetary, and one health: Mapping the evidence via bibliometric content analysis

Background Amidst an anthropogenic climate and ecological crisis, the conventional understanding of Health Literacy has been expanded to address socio-ecological determinants of health through the Planetary Health Literacy, Climate and Health Literacy, or One Health Literacy concepts. However, the field's interdisciplinary character and its recent evolutionary status have led to theoretical fragmentation and a lack of conceptual debate. Methodology To test three expectations regarding the conceptual underpinnings of literacy and competency concepts and to systematically map the evidence, a bibliometric content analysis is conducted using co-occurrence analysis (COA). Findings A total of 135 peer-reviewed studies meeting the inclusion criteria are analyzed from 1444 screened publications. COA via bibliometric network viewer VOSviewer yields the formation of four distinct clusters: 1) Competencies in Planetary Health Education and sustainable healthcare; 2) Environmental Health Literacy and environmental risk and exposure awareness; 3) Competencies regarding One Health, the animal-human-health nexus and interdisciplinary education; 4) Food Literacy, nutrition, and sustainability. Analyzing patterns of single items underscored One Health and Planetary Health as broadly integrative themes, whereas other concepts remained cluster-specific. The hypothesized distinction between One Health and Planetary Health Literacy is omitted, whereas conceptual differences between Environmental Health Literacy and Planetary Health Literacy are confirmed. Conclusion The findings contribute to theoretical and methodological research trajectories and reveal the widespread use of vague terms such as knowledge, skill, or attitude over differentiated literacy constructs. The results underscore the need for standardized terminology and conceptual underpinnings, particularly within educational research.