JMIR Publications

ABSTRACT

Background:

Phthalates, a class of environmental hormones widely used in plastics and personal care products, are associated with endocrine disruption, metabolic disorders, and reproductive dysfunction. Women are particularly vulnerable due to frequent exposure through cosmetics and household products. Health literacy plays a critical role in reducing environmental risk behaviors; however, traditional paper-based education has limited reach and engagement.

Objective:

This randomized controlled trial evaluated the effectiveness of an eHealth educational intervention (Phthalates Free) in improving women’s health literacy regarding environmental hormones and phthalate exposure, and examined whether user engagement influenced intervention effectiveness.

Methods:

A double-blind randomized controlled trial was conducted in the outpatient department of a regional teaching hospital in Taipei, Taiwan. A total of 114 women were randomly assigned to an intervention group (n = 58) receiving a 6-month eHealth platform–based education program and a control group (n = 56) receiving conventional paper-based education. Assessments were conducted at baseline (T0), 3 months (T1), and 6 months (T2). The Phthalate Health Literacy Scale (10 items; α = .90, CVI = 0.93) measured overall and domain-specific literacy (health care, disease prevention, and health promotion). Data were analyzed using intention-to-treat principles with generalized estimating equations (GEE) and ANCOVA, controlling for marital status, education, occupation, waist circumference, and pregnancy history. System usability and engagement were assessed using the System Usability Scale (SUS) and backend analytics.

Results:

At 6 months, the intervention group showed a significantly greater increase in total health literacy than the control group (+9.93 points, Wald χ² = 17.74, p < .001). Domain analyses revealed significant improvements in health care (+1.52, p = .001), disease prevention (+1.32, p = .001), and health promotion (+1.12, p = .001) domains. ANCOVA confirmed the between-group difference at T2 after adjusting for baseline scores (F = 11.43, p = .001; adjusted mean difference = 7.15, 95% CI 2.96–11.34). Engagement analysis showed that high-engagement users (n = 10) scored significantly higher in overall health literacy (t = –3.00, p = .004) and all domains than general users. The SUS results (mean 84.7, SD 5.2; response rate 79.3%) indicated excellent usability and acceptance of the platform

Conclusions:

The Phthalates Free eHealth educational intervention significantly improved women’s overall and domain-specific health literacy related to phthalate exposure, with the most substantial gains observed in the health promotion domain. Higher engagement frequency was positively associated with literacy improvement, demonstrating a clear dose–response relationship. These findings highlight the potential of digital health interventions as scalable, interactive, and evidence-based tools for enhancing environmental health literacy. Such platforms can complement conventional education methods, promote behavior change, and support public health efforts to reduce exposure to environmental hazards. Clinical Trial: ClinicalTrials.gov NCT05024227