Health Belief Model–Based Education to Improve Water Intake and Hydration in Older Adults: A Randomized Controlled Trial

Purpose: The current randomized controlled trial examined the effects of Health Belief Model (HBM)–based education on daily water intake, hydration biomarkers, thirst discomfort, and dry eye complaints in older adults. Method: Eighty community-dwelling older adults aged ≥65 years with insufficient daily water intake (<1 L/day) were screened and randomly assigned to intervention ( n = 40) and control ( n = 40) groups. Eligibility was determined using predefined inclusion criteria and baseline assessments. The intervention included individualized HBM–based education supported by a booklet and intake log. Data were collected using a descriptive form, Thirst Discomfort Scale, Ocular Surface Disease Index, and refractometer-based measurements of urine specific gravity and refractive index. Results: Postintervention mean daily water intake significantly increased in the intervention group (mean = 749.8 [ SD = 176] mL vs. 572.9 [ SD = 159.3] mL; p < .001). Thirst discomfort scores decreased, and between-group differences were found in urine specific gravity and refractive index ( p < .001). Although Ocular Surface Disease Index scores improved ( p = .002), the clinical impact was limited. Conclusion: HBM–based education increased water intake and reduced thirst discomfort, supporting community-based geriatric nursing practice. Future studies should examine long-term effects and support integration of theory-based hydration education into nursing training and clinical practice.