The effect of educational intervention based on the mobile application on women’s knowledge, attitude, and practice on microplastics and health: study protocol for a randomized controlled trial

Abstract

Background

The pervasive issue of microplastic (MP) contamination is undeniable. The primary solution to this global problem lies in significantly reducing the amount of plastic entering the environment. Addressing such a large-scale issue is no easy feat. However, a necessary strategy involves public education. In parallel, a randomized controlled trial (RCT) aims to evaluate the effect of interventional education via a mobile phone application on improving women’s knowledge, attitude, and practice regarding the health effects of MPs.

Methods

This randomized controlled trial includes three phases. In the first phase, a questionnaire assessing women’s knowledge, attitudes, and practices (KAP) regarding microplastics will be developed and validated. In phase two, educational content for the mobile application “PlastiWise” will be created based on behavior change constructs. In phase three, a two-arm, parallel-design RCT will be conducted with 136 women aged 18 years and older who own smartphones, have basic literacy skills, and provide informed consent. Participants will be recruited through an online call disseminated via social media platforms and health system networks in Iran. They will be randomly assigned to an intervention group (n = 68) receiving the educational program through the app or a control group (n = 68). The sample size was calculated using G*Power software to ensure sufficient power (80%) with an alpha level of 0.05, factoring in a 15% dropout rate. Primary outcome data (KAP scores) will be collected at baseline, immediately post-intervention, and 8 weeks post-intervention using self-reported questionnaires. Data analysis will include descriptive statistics and inferential tests, such as independent t-tests and paired t-tests, to assess group differences and within-group changes over time.

Discussion

Implementing an educational intervention on knowledge, attitude, and practice (KAP) about MPs using a mobile application will be a first in Iran. This research is expected to benefit Iranian women by contributing evidence on factors that might influence the effectiveness of educational training related to MP consumption.

Trial status 

Protocol version 1, 2024–07-12. The enrolment of participants began on 2024–09-22. The recruitment is estimated to be completed by 2024–11-21.

Trial registration 

Iranian Clinical Trial Register IRCT20240529061941N1.https://irct.behdasht.gov.ir/user/trial/77069/view. Date is July 12, 2024.

Background

Plastics are made up of building blocks called monomers, which include elements like carbon, hydrogen, and oxygen. Their affordability, durability, and resistance to heat and electricity make them widely used. In 2020, the world produced about 350 million tons of plastic [1]. Iran, a developing country, is among the top 10 plastic producers. Current data shows that Iran produces over 17,000 tons of plastic per year, and 50 tons per day, with each citizen contributing three pieces of plastic to the environment daily [2, 3]. Exposure to various factors can break down plastics into microplastics (MPs), which then pervade the ecosystem, exacerbating plastic pollution [4]. These minute particles can infiltrate living organisms and, when ingested, can build up in tissues and organs, posing health risks [4]. Researches indicate that MPs can circulate within an organism, accumulate in various tissues, and induce oxidative stress by elevating free oxygen radicals [5].

MPs, prevalent in various aspects of human life, find their primary applications in health and cosmetic sectors. These tiny plastic particles, known as microbeads, measure between 1 and 4 mm in diameter and are commonly found in personal care and health products such as toothpaste, makeup, and deodorant [6]. A study conducted by Lei et al. estimated that nearly 40 million tons of MPs have been discharged into the environment due to the usage of personal care and cosmetic products that contain these particles [7]. The pervasive issue of MP contamination is undeniable. The primary solution to this global problem is a significant reduction in the amount of plastic entering the environment. Addressing such a large-scale issue is no easy feat. It necessitates public education, product innovation, industry leadership, and a robust commitment from local, national, and international governments to decrease microplastic usage and understand its impact on ecosystems and human health [8].

Social and behavior change (SBC) programs, which encompass activities targeting key determinants like knowledge and attitudes, are recognized as cost-effective, fundamental, and universal strategies for driving behavior change and improving health outcomes [9]. Health education, as a discipline devoted to enhancing health and reducing adverse health determinants, plays a pivotal role in promoting the well-being of individuals, families, and societies. Achieving behavioral change necessitates strengthening knowledge (K), refining attitudes (A), and improving practice (P), in alignment with the KAP framework. Women play pivotal roles within families and communities, serving as vital agents of change due to their multifaceted responsibilities and social influence. Their active engagement in managing family health, education, and well-being positions them as central figures in fostering sustainable behavioral changes. Women’s social networks, including kin, friends, and religious associates, are instrumental in resource sharing and creating communal support, especially in pastoral and fragmented communities [10]. Furthermore, their involvement in community rituals, such as funeral management under Islamic law, has progressively reshaped societal perceptions, acknowledging their competence in diverse social domains [11]. Many women demonstrate resilience and adaptability by successfully balancing work and family responsibilities, despite the challenges posed by traditional norms [12]. Women’s empowerment in reproductive decision-making and family planning further reflects their capacity to drive significant societal changes, even amidst socio-cultural barriers [13]. Their participation in religious activities enhances community development, while their contributions to cultural preservation and economic stability underscore their broad influence [14]. Within the Iranian cultural context, women, particularly housewives, act as health ambassadors, promoting informed decisions and behaviors among family members [15]. Consequently, educating women about microplastic management aligns with leveraging their intrinsic role in shaping family and community health dynamics, fostering a more sustainable and informed society [16]. Over the past years, numerous studies have explored the detrimental effects of MPs on the natural lives of plants and other organisms [17, 18]. Despite these efforts, research on MPs remains inadequate. It is imperative to prioritize the issue of microplastics in new studies promoting healthy behavior. Effective educational methods can drive behavior changes to improve people’s lifestyles [19]. Thus, it is essential to reassess educational methods and select the most effective approaches to guide people toward better self-learning and assist them in making informed health decisions [20, 21]. Digital technology and multimedia environments are among the tools that can aid in this endeavor [22]. Educational software such as mobile application, with advantages such as repeatable lessons, reminders, personalized education, and flexibility in time and location, can significantly improve traditional teaching methods and reduce psychological barriers, thus playing a crucial role in supporting user self-learning [20,21,22].

Although extensive research has examined the environmental and biological impacts of microplastics, there is a noticeable gap in studies focusing on interventions designed to educate and empower individuals, particularly women, to adopt preventive behaviors. Furthermore, the application of digital educational tools, such as mobile apps, in addressing microplastics’ health impacts has been insufficiently explored in both global and Iranian contexts. Despite their central role in promoting family and community health, women’s engagement in microplastic management remains under-researched. This study contributes to the limited body of knowledge by utilizing a mobile application to address microplastic-related behaviors, evaluating its efficacy compared to traditional educational methods. The use of a control group in this study will allow for validation of the effectiveness of the mobile app as a digital educational approach. The objective of the study is to determine the effect of an educational intervention on women’s knowledge, attitudes, and practices regarding the health effects of microplastics. The study hypothesis is that there will be a significant difference between the experimental group and the control group in terms of knowledge, attitudes, and practices related to microplastic pollution before, immediately after, and 2 months following the educational intervention.

Trial design

This protocol for paralleled randomized controlled trial (RCT as a pilot project was developed according to the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT 2013 checklist) (Additional file 1: S1) [17].

Methods

Study setting

This randomized controlled trial will be conducted across various regions of Iran, targeting women who meet the inclusion criteria. The study does not focus on a specific geographic site, such as a clinic or hospital, but rather encompasses a nationwide sample. Women from diverse urban and rural settings will be recruited, representing a broad demographic cross-section of the country. Given the wide reach of the mobile application used for the educational intervention, participants can be from any province or region of Iran, provided they have access to the internet and meet the eligibility criteria. This approach allows for generalizability across various social, cultural, and economic backgrounds, ensuring the findings are applicable to women from different parts of the country. No physical study sites will be established for this trial, as all data will be collected digitally through the mobile application and online surveys. Therefore, a formal list of study sites is not applicable.

Eligibility criteria

Participants must provide written, informed consent before any study procedures take place. The following inclusion and exclusion criteria will be applied at the time of randomization.

Inclusion criteria

Participants will be eligible for inclusion in the trial if they meet all of the following criteria:

• 1. Women aged 18 years and older.

• 2. Literate in reading and writing.

• 3. Willing to participate with informed consent and share relevant information.

• 4. Own a smartphone and have the ability to use it.

• 5. Willingness to engage in the study’s educational intervention.

• 6. Ability to understand and complete the study questionnaire.

Exclusion criteria

Participants will be excluded from the trial if they meet any of the following criteria:

• 1. Currently enrolled in a parallel training program related to microplastics or health education to avoid potential contamination of intervention effects.

• 2. Failure to complete the required questionnaires at any of the designated time points (pre-test, post-test 1, or post-test 2) to ensure data integrity.

• 3. Explicitly expressing disinterest in the study topic or unwillingness to engage with the educational content.

• 4. Lack of access to a smartphone or the internet, which are essential for using the PlastiWise app and participating in the trial. A complete list of inclusion and exclusion criteria is available in Table 1.

Table 1 Inclusion and exclusion criteria

Intervention: description of trial

The trial will be conducted in three phases: phase 1: development and psychometric assessment of the tool, phase 2: app framework and content development, and phase 3: randomized controlled trial (RCT).

Phase 1: development and psychometric assessment of the tool

The first phase focuses on the development and psychometric evaluation of the KAP questionnaire. Based on a comprehensive literature review, we will create items that assess women’s knowledge, attitudes, and practices regarding the effects of microplastics on health. The developed questionnaire will undergo a rigorous psychometric evaluation to assess its validity and reliability [23]. In brief, the psychometric evaluation of the questionnaire included the following steps.

Phase 1: development and psychometric assessment of the tool

The first phase of the study will involve the systematic development and psychometric evaluation of the MIKAP questionnaire to assess women’s knowledge, attitudes, and practices (KAP) regarding microplastics (MPs) and health. The process will follow established methodologies for tool development and validation.

Face validity

To establish face validity:

• a) Qualitative face validity: Individual interviews will be conducted with 10 women from the target population to assess item simplicity, clarity, and relevance. Feedback will guide revisions to ensure items are understandable and culturally appropriate [24, 25].

• b) Quantitative face validity: Items will be scored on a 5-point Likert scale (from “not at all important” to “strongly important”). Impact scores will be calculated, with values above 1.5 considered acceptable [24, 25].

Content validity

• a) Qualitative content validity: 10 experts in health education, environmental health, and questionnaire development will review the items for content relevance and style. Their feedback will inform item refinement.

• b) Quantitative content validity: The same expert panel will rate items using the content validity ratio (CVR) and content validity index (CVI). A CVR > 0.62 and ICVI ≥ 0.80 will indicate acceptable validity, while the scale CVI (SCVI) should exceed 0.90 [24, 25].

Item analysis

A preliminary evaluation will be conducted with 50 women from the target population. Items will be assessed for mean, standard deviation, and correlation with other items. The loop method will evaluate internal consistency, retaining items with correlations ≥ 0.3.

Construct validity

Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) will assess the questionnaire’s structure. CFA will assign items to factors based on theoretical domains, using robust methods suitable for ordinal data. Acceptable fit indices will include RMSEA < 0.06, GFI > 0.90, and χ²/df < 2 [26].

Reliability

• a) Internal consistency: Cronbach’s alpha and composite reliability (CR) will be calculated. A Cronbach’s alpha ≥ 0.70 will indicate acceptable reliability.

• b) Stability: The intraclass correlation coefficient (ICC) will measure test–retest reliability over a 2-week interval, with ICC > 0.75 considered excellent.

Absolute reliability

Absolute reliability will be assessed by calculating the minimum important change (MIC) and minimum detectable change (MDC). MIC values should exceed MDC to demonstrate practical significance.

Scoring

The total score of the MIKAP questionnaire will range from 1 to 100. Thresholds for ceiling and floor effects will be set at < 20%.

Feasibility

The feasibility of administering the questionnaire will be assessed by calculating the average time required for completion and participants’ feedback.

The product of this phase will be resulted in “Microplastic Knowledge, Attitude, and Practice (MIKAP) Assessment Tool,” a valid and reliable questionnaire that will be developed specifically for this study.

Phase 2: app framework and content development

The aim of this phase is to create an educational mobile application (“PlastiWise app”) that integrates evidence-based content and user-friendly functionality to promote knowledge, attitudes, and practices (KAP) related to microplastics and health. This step is divided into two following steps.

Step one: educational content (EC) development

EC will be based on the latest national and international literature for the MP and human health [27] and the finding of the pre-test stage. The EC outlined MP and human health and structured around the three cognitive domains of knowledge, attitude, and practice. These potential general outlines might need to be modified to fit the specific context and requirements of our study.

Step two: designing a mobile app

Based on our previous studies, preliminary functional modules of the app will be collected. The next step of this study is to search and evaluate currently existing domestic issues on MP-related apps on the App Store and Android Market. We use the words “MP/Plastic” respectively to search for related apps. Each eligible app will be downloaded and its features, including names, download numbers, target population, and main function modules, will be listed and analyzed. Personal face-to-face interviews with periodical experts will be held to discuss the framework of the app from the interactivity, feasibility, acceptability, and user experience aspects. Finally, the functional modules of the app will be determined. The application that is going to be made is based on the Android platform, and since the main language of the Android operating system is Java, it will be made with the Java programming language. The app will be developed by a company that specializes in mobile application development. After the app development is completed, 10 participants will be invited to test it, and necessary modifications will be made according to their pieces of advice [28]. The main output of this phase will result in a mobile application named “PlastiWise app,” containing educational content related to three main behavior change constructs: knowledge, attitude, and practice regarding MPs.

Phase 3: randomized controlled trial (RCT)

For evaluating the effectiveness of the app-based intervention follow three main stages as (a) pre-test, (b) educational intervention (EI) via smartphone-app training, and (c) two post-tests. The framework of this trial is informed by the KAP model (knowledge, attitude, practice), which serves as the foundation for the intervention. By using this theoretical framework, we aim to ensure that the intervention is grounded in established principles of behavior change. This model guides the development of the educational content and determines the primary outcomes we aim to influence: knowledge, attitudes, and practices related to microplastics and health. So, the study design follows a randomized controlled trial (RCT) framework, with participants randomly assigned to either the intervention or control group. Data collection will take place at three time points (baseline, immediately post-intervention, and at 8-week follow-up). The trial follows standard RCT procedures to ensure randomization, control, and rigorous evaluation of outcomes.

• a) Pre-test stage

In the pre-test stage, all participants will be assessed on their existing knowledge. Both A (smartphone-app training), and B (control) groups will receive an online questionnaire distributed through popular social media platforms such as Eitaa and Bale. Once group A finishes the pre-test, they will proceed with the training mobile app installation in EI stage.

In educational interventions, one of the most critical steps is the preparation of educational materials, which is typically informed by pre-test results. In this study, the educational content will be designed around the three core constructs of behavior change—knowledge, attitude, and practice—focusing on microplastics and human health, as determined by the pre-test findings. Prior to implementing the educational intervention, it is essential to address key steps in displaying this content through a mobile application, ensuring its effectiveness and user engagement.

• b) Educational intervention (EI)

They could access EC at any time and place for 4 weeks via mobile application. For privacy considerations, accessibility to the app for each person was personalized with their username and password which was provided at the initial registration. Each of the participants in experiment group (A) will be required to register as a user to download the PlastiWise app separately. EC for the PlastiWise app is outlined in Table 2. The participants in the smartphone training group (A) will be informed that they will ask the facilitator if they have any additional unresolved issues in this specific area.

• c) Post-test stage

Table 2 Schedule of enrollment, interviews, intervention, and assessment of the educational intervention trial, following the Standard Protocol Items Recommended for Controlled Trials (SPIRIT) guidelines

Following the training period, both groups (smartphone training and control) will complete the first post-test immediately and 8 weeks (2 months) after the intervention ends (Fig. 1).

Fig. 1

The flowchart for selecting women for the randomized controlled trial, following the CONSOR

Control group (CG)

Participants in the CG will be invited to maintain their routine activities and will not receive any structured training content during the intervention period. To ensure ethical compliance, CG participants will be exposed to unstructured information about MPs and human health in various formats, including brochures, videos, and Instagram posts, as part of routine public awareness efforts. Additionally, at the end of the 8-week intervention, CG participants will receive access to the educational content available in the PlastiWise app to ensure equitable knowledge dissemination. The study design is depicted in Fig. 2 to facilitate comprehension of the research process.

Fig. 2

The study design process

Interventions: adherence

To ensure adherence to the intervention protocol in this study, several strategies will be implemented. These strategies aim to promote engagement with the mobile application-based educational intervention and monitor participant compliance throughout the trial:

• 1. Automated reminders: Participants will receive regular notifications and reminders via the social media by the first study administrator (ZS) to complete the educational modules and the pre- and post-intervention questionnaires. These reminders will be personalized to encourage consistent engagement with the content.

• 2. Monitoring and follow-up: Study administrator will monitor participants’ completion rates for both the educational modules and the questionnaires. If any participant shows a lack of progress or fails to complete a required task, they will receive follow-up messages or phone calls to encourage continued participation.

• 3. Incentives: As an additional measure, small incentives (e.g., digital certificates of completion) may be offered to participants who fully engage with and complete all aspects of the study, including the educational intervention and questionnaires. Additionally, to ensure equal access to the intervention and eliminate barriers related to internet availability, free internet access will be provided to all participants in both the intervention and control groups throughout the trial duration

Interventions: concomitant care

The selection of participants will be designed to minimize cross-contamination between intervention and control groups by ensuring that participants are unaware of each other’s involvement, given the remote nature of the mobile application.

Outcomes measure

The initial research question addressed in this study is “Does the educational intervention based on mobile app affect KAP of Iranian women about the health effects of MPs?”. To answer this main question, the following primary and secondary outcomes are expected.

Primary outcome measure

The primary outcomes will be assessed using the Microplastic Knowledge, Attitude, and Practice (MIKAP) Assessment Tool, a valid and reliable questionnaire developed specifically for this study during the tool development phase. The outcomes are as follows:

• Knowledge of MPs: Measured using the MIKAP tool, which includes items designed to assess participants’ factual understanding of MPs and their health effects.

• Attitude toward MPs: Evaluated through attitudinal items in the MIKAP tool that assess participants’ perceptions, beliefs, and feelings about MPs and related behaviors.

• Practice related to MPs: Measured using behavioral items in the MIKAP tool that assess the extent to which participants engage in practices to reduce exposure to MPs and minimize plastic use.

Each outcome will be measured at three time points of baseline (pre-test), immediately after intervention completion (post-test 1), and 2 months post-intervention (post-test 2). The MIKAP tool is psychometrically validated, ensuring reliable and accurate measurement of these constructs.

Secondary outcomes measure

Self-reported health status

Participants’ self-perceived health status will be assessed using a structured questionnaire both before and after the intervention. While not directly linked to MPs, this measure aims to provide additional insights into participants’ overall perception of their health, which may indirectly reflect the potential influence of increased knowledge and practices on well-being.

Knowledge retention

A follow-up assessment will be conducted 6 months post-intervention to evaluate the retention of knowledge gained from the educational program. The same validated MIKAP assessment tool used to measure primary outcomes will be utilized to ensure consistency. This measure is intended to gauge the long-term effectiveness of the intervention in sustaining knowledge improvement over time.

Participant timeline

Participants will be enrolled at two main points: during the development of the assessment tool and before the randomized trial begins. The intervention will be delivered through a mobile application, and follow-up assessments will take place after the completion of the intervention to measure its effectiveness. The schedule of participant enrollment, intervention, and assessment is outlined in Table 3. Key timepoints include the initial baseline enrollment, allocation, post-allocation follow-ups, and the final closeout assessments. The baseline data will include variables such as age, education level, marital status, economic status, and employment status, while the outcome variables will focus on knowledge, attitude, and practice (KAP) constructs related to microplastics and health.

Table 3 Educational content outline for MPs and human health: a focus on knowledge, attitude, and practice

A schematic diagram can be found in Table 2, detailing the specific timepoints (T0, T6, T8, T9, T11) for enrollment, intervention, and follow-up assessments.

Sample size

The sample size for this study was determined to ensure sufficient power to compare participation between the experimental and control groups. Participants will be equally allocated to these two randomization groups. Based on the study by Miraç and Fatoş [29], and using G*Power 3.1 software, a sample size of 59 participants per group was calculated, assuming an alpha level of 0.05, a power of 0.80, and an effect size of 0.740. To account for a potential dropout rate of 15%, this number was adjusted to 68 participants per group. Consequently, the total sample size required for the study is 136 participants (68 in each group). These calculations were guided by the following formulas:

$$n=\frac{\underline{x_{1\;}}-\underline{\;x_2}}{\sqrt{S^2(\frac1{n_1}+\frac1{n_2})}}$$

$${S}^{2}=\frac{\left({n}_{1}-1\right){S}_{1}^{2}+({n}_{2}-1){S}_{2}^{2}}{({n}_{1}+{n}_{2}-2)}$$

Confidence level	α = 0.05
Test power	π = (1 − β) = 1 − 0.01 = 0.99
Mean response changes in the control grou	$\underline{x_1}=0.1097$
Mean response changes in the training group	$\underline{x_2}=-0.0896$
Sample variance in the control group	${S}_{1}^{2}=0.35$
Sample variance in the training group	${S}_{2}^{2}=0.15$
Effect size	$\Delta =0.740$
Estimate the total sample size	n = 118

Recruitment

Recruitment for this study will begin with an online call disseminated through various popular social media platforms in Iran, including Instagram, WhatsApp, Telegram, Eitaa, and Bale. Additionally, the recruitment announcement will be shared via the Seeb platform (Integrated Health System) in Iran’s Primary Health Care Centers (IPHC), as well as through channels and networks associated with the Iranian Association for Women’s Studies (IAWS) and the Women’s Empowerment Office in Tehran Municipality (Table 3).

The online call will remain active for 1 week and will present the eligibility criteria for participation in the form of an online checklist. Prospective volunteers will be compiled into a list and subsequently refined based on the study’s inclusion criteria. Each volunteer will undergo an individual compliance check with the entry criteria through a phone call. These recruitment processes will be managed by a trained research assistant (ZS; the first author) to ensure accuracy and consistency. This multi-faceted recruitment strategy aims to achieve adequate participant enrollment to meet the target sample size, leveraging both online platforms and community networks to reach a diverse group of potential participants.

Randomization

Once the list of eligible individuals is prepared and numbered consecutively, the random allocation of the 136 participants to two groups, A and B, will take place. This will be achieved using the method of permutation blocks and a randomization list generated by a computer (R software using a binomial distribution). Following simple randomization procedures, participants will be assigned to one of the two arms of the trial in a 1:1 ratio according to a computer-generated randomization schedule via https://www.sealedenvelope.com/simple-randomiser/v1/lists. The letter A will be considered for the intervention group, the letter B will be considered for the control group. To maintain the integrity of the study, the allocation sequence will remain hidden from the participants and researchers involved in the trial. The randomization sequence is predetermined and designed to guarantee an equal distribution of participants in both groups. In this study, all block sizes are equal, ensuring that out of the total of 136 people, groups A (the group trained by the mobile application method) and B (the control group) will each receive 68 people. Each participant will receive a unique code related to their group allocation, ensuring that any differences in results between groups are due to training and not selection bias. For randomizing samples and assigning a code to each participant, the envelope method will be used. Envelopes, prepared by one of the research team members and containing random numbers from the Randomize.com site, will be printed and sealed. The envelopes will be prepared by a member of the research team who is not involved in participant recruitment or data collection to ensure allocation concealment. The trained research assistant (ZS) will then explain the purpose of the study by phone to those eligible to enter the study. If the person expresses a desire to participate in the study, they will be asked to send an informed consent form via email or a registered phone number on one of the social networks like WhatsApp, Telegram, Eitaa, and Bale. The applicant to participate in the study is then allowed to open an envelope on their behalf. The trained research assistant opens the packet and based on the contents of the envelope, the person is allocated to either the intervention or control group.

Data collection plan

The data collection for this randomized controlled trial will take place at three critical time points: at baseline (pre-test), immediately after the intervention (post-test 1), and 8 weeks following the intervention (post-test 2). The study will run from late September to November 2024. A self-reported questionnaire; Microplastic Knowledge, Attitude, and Practice (MIKAP) Assessment Tool; designed to measure Knowledge, Attitude, and Practice (KAP) related to microplastics, will be the tool for data collection.

Phase 2: baseline data collection

At baseline (pre-test), participants will complete the KAP questionnaire to assess their initial knowledge, attitudes, and practices regarding microplastics. This will establish a baseline for comparison with subsequent time points.

Phase 3: post-intervention data collection

Post-test 1 will be conducted immediately after the intervention, and participants will again complete the KAP questionnaire to measure changes in their knowledge, attitudes, and practices. The results will help assess the immediate impact of the intervention.

Phase 4: follow-up data collection

Post-test 2 will be administered 8 weeks after the intervention to evaluate the sustainability of the behavior changes and long-term effects of the intervention.

Retention strategies

To ensure complete follow-up, participants will receive digital certificates as an incentive. We will also employ retention strategies, including regular reminders via phone calls or text messages and flexible time slots for completing assessments. Participants who deviate from the intervention protocol will still be asked to complete the follow-up assessments, and their data will be included in the analysis.

Data management

All data will be entered electronically into SPSS software using double-entry to ensure accuracy. Data coding will be standardized across all variables to maintain consistency. Range checks will be employed to identify outliers or erroneous entries, and missing data will be flagged for imputation during analysis. Data will be stored on a secure, password-protected server, and access will be limited to authorized personnel only. Participant consent forms will be stored separately from the data files to maintain confidentiality.

Statistical methods for outcomes

Descriptive statistics (mean, standard deviation, percentiles) will be used to summarize participant demographics and baseline characteristics. Inferential statistics will be applied to assess the primary and secondary outcomes. An independent t-test or Mann–Whitney U test will be used to compare the KAP scores between intervention and control groups. Paired t-tests or Wilcoxon signed-rank tests will be applied to assess changes within groups over time. The Kolmogorov–Smirnov test will be used to assess data normality. To align with the study’s objective, repeated measures ANOVA (for normally distributed data) or the Friedman test (for non-normally distributed data) will be employed to evaluate differences in KAP scores over three time points (baseline, immediately after, and 2 months post-intervention) between groups.

Additional analyses

Additional analyses will include subgroup analysis based on demographic variables such as age, education, and economic status to examine potential moderating effects on the intervention outcomes. Subgroup analyses will be conducted by stratifying participants into subgroups (e.g., age groups: < 30 years and ≥ 30 years; education: less than high school, high school, higher education). The primary outcomes will then be reanalyzed within each subgroup using the same statistical tests outlined above. Adjusted analyses may also be conducted to control for confounding variables. Multivariate regression models will be used to assess the interaction effects between subgroup characteristics and intervention outcomes while adjusting for potential confounders such as baseline KAP scores and demographic factors.

Analysis population and missing data

The analysis will follow the intention-to-treat principle, meaning all participants who were randomized will be included in the final analysis regardless of protocol adherence. Missing data will be handled using multiple imputation techniques where appropriate, and sensitivity analyses will be conducted to assess the robustness of the findings. Specifically, multiple imputations will be performed using chained equations (MICE) to estimate missing values based on observed data. The imputation model will include baseline characteristics, group assignment, and outcome variables. Additionally, a complete-case analysis will be conducted alongside the imputed dataset to compare results and ensure consistency.

Monitoring

Data monitoring: formal committee

A formal Data Monitoring Committee (DMC) will not be established for this trial. The study involves a low-risk educational intervention delivered via a mobile application, and there is no anticipated serious harm or adverse effect. Given the low-risk nature of the intervention, the research team has determined that a DMC is not necessary. Instead, the principal investigator (PI) will oversee the monitoring of data collection and trial progression, ensuring adherence to the protocol. Any deviations will be documented and reported in regular meetings among the research team members.

Data monitoring: interim analysis

No interim analyses are planned for this study, as the educational intervention is unlikely to have immediate, harmful effects. The trial will run until the completion of data collection at the three designated time points (baseline, immediately post-intervention, and 2 months post-intervention). If any unexpected adverse events arise during the study, the research team will review the data and decide whether to continue or terminate the trial. The final decision to terminate the trial will rest with the principal investigator and the research ethics board overseeing the study.

Harms

The trial involves minimal risk due to the nature of the mobile-based educational intervention. Nonetheless, plans are in place to collect and assess any adverse events or unintended effects. Participants will be encouraged to report any issues or discomfort they experience during the intervention period. A standard form will be used to document any solicited or spontaneously reported adverse events, and the research assistant will regularly follow up with participants to ensure safety. The PI will review all reports of adverse events and determine the severity and need for further action.

Auditing

There are no formal plans for external auditing of the trial conduct. However, internal audits will be conducted at regular intervals by the research team to ensure protocol adherence, data accuracy, and ethical conduct. The PI will review progress reports every month, checking data entry, randomization procedures, and informed consent processes. If any irregularities are found, corrective actions will be implemented. The internal auditing process is independent of any sponsor or funding agency to avoid potential conflicts of interest.

Ethics and dissemination

Research ethics approval

The study protocol was ethically approved by the Faculty of Medical Sciences, Tarbiat Modares University of Iran (reference number: IR.MODARES.REC.1403.041). The research team will adhere to the Declaration of Ethical Principles for Medical Research throughout the study.

Protocol amendments

Plans for communicating significant protocol modifications, such as changes to eligibility criteria, outcomes, or analyses, will involve notifying relevant parties, including investigators, study participants, and study registries. The corresponding author will be responsible for documenting and communicating these changes in a timely manner.

Consent or assent

Informed consent will be obtained from all potential trial participants by a trained research assistant. Participants will receive a comprehensive explanation of the study’s purpose, procedures, and their rights before signing a written consent form. They will also have the opportunity to ask questions prior to providing consent.

Consent or assent: ancillary studies

Not applicable. There is no additional consent provisions required for the collection and use of participant data and biological specimens in ancillary studies, as this study does not involve ancillary research.

Confidentiality

All personal information regarding participants will be collected, stored, and maintained in a manner that protects confidentiality. Data will be de-identified, and no personal identifiers will be used in data storage. Only members of the research team will have access to the data collected during the study, ensuring confidentiality is upheld throughout the trial.

Declaration of interests

All principal investigators and study site members will declare any financial and other competing interests related to the trial. These declarations will be documented and reviewed to ensure transparency and integrity in the research process.

Data access

Access to the final trial dataset will be limited to the principal investigator and designated research team members. No contractual agreements will restrict access to the dataset, ensuring that all involved in the study can analyze the results.

Ancillary and post-trial care

There are no specific provisions for ancillary and post-trial care beyond the normal follow-up provided to all participants. Participants will be informed about any relevant health resources or support services if needed, and they can withdraw from the study at any time without penalty.

Dissemination policy: trial results

The trial results will be communicated to participants, healthcare professionals, and the public through publication in peer-reviewed journals and presentations at relevant conferences. Participants will receive a summary of the findings upon request. There are no publication restrictions anticipated.

Dissemination policy: authorship

Authorship eligibility guidelines will follow the International Committee of Medical Journal Editors (ICMJE) recommendations. All contributors meeting the authorship criteria will be acknowledged in publications, and no professional writers will be used in the preparation of manuscripts.

Dissemination policy: reproducible research

Plans for granting public access to the full protocol, participant-level dataset, and statistical code will be considered after the study’s completion. The research team aims to promote transparency and reproducibility by making this information available in a public repository.

Discussion

This randomized controlled trial has the potential to address three main cognitive domains for health behavior change processes. Firstly, this research is expected to benefit Iranian housewives by adding to the evidence of what factors might influence the effectiveness of educational training on knowledge about MP consumption. Awareness is theorized to be the initial step influencing behavior change processes, and “seeking information behavior” following sensitization with more details and information might lead to knowledge [30]. Secondly, our understanding of attitudes about MP and the influence of how beliefs and even myths influence MP management consumption among Iranian women will be enhanced. Attitudes are theorized to significantly influence behavior change processes. Through this study, we expect to contribute new attitude about factors influencing MP consumption management among Iranian women. Lastly, we also expect our trial to influence the practices of Iranian women regarding MP management consumption, completing the final chain of the behavior change process. KAP surveys, as shown by Gumucio et al. [31], establish baseline data for measuring the effectiveness of health education efforts, empowering policymakers to efficiently allocate resources to areas of greatest need [32].

This study not only aims to improve the knowledge, attitudes, and practices of Iranian women regarding MP consumption management through a planned educational program but also seeks to achieve two additional milestones. The development of a valid and reliable instrument to assess KAP regarding MP consumption and the creation of a user-friendly mobile training application, “PlasiWaise,” in Persian, exemplify innovative steps toward effective health education. This will be the first training application in Farsi (Persian) to cover all three KAP constructs. “PlasiWaise” is designed to be user-friendly, informative, and attractive, incorporating all the essential elements of effective training apps. Mobile health interventions (mHealth) have emerged as a promising strategy for delivering health education, particularly among women facing time constraints [33]. Studies have shown that mHealth interventions can be effective in improving knowledge, attitudes, and self-care practices related to various health topics [34].

Probable limitations

The current study design, like any study, has some limitations:

• Data collection method: While a randomized controlled trial with a control group is considered ideal for establishing causality, resource constraints make face-to-face data collection in such a design impractical. This study therefore relies on self-reported data through surveys and potentially within the mobile application “PlasiWaise.”

• Self-reported data and social desirability bias: Self-reported data can be susceptible to social desirability bias, where participants might report behaviors considered more socially desirable or what they believe researchers want to hear. This could lead to an overestimation of knowledge acquisition or positive changes in attitudes and practices related to MP consumption.

Conclusion

In conclusion, it is evident that addressing the issue of MP consumption and its management among Iranian women requires a multifaceted approach. The randomized controlled trial aims to tackle three key cognitive domains for health behavior change: awareness, attitudes, and practices. By enhancing knowledge through educational training, understanding attitudes and beliefs, and improving practices regarding MP management, this study is expected to make significant strides in influencing health behaviors. In conjunction with these efforts, it is imperative to acknowledge the broader context of solving the MP problem. Public education, product innovation, and industry leadership, alongside strong governmental commitment at local, national, and international levels, are crucial for reducing MP usage and comprehending its ecological and health impacts. The implementation of a training program, as indicated by the results, can play a critical role in reducing plastic production. Additionally, the establishment of plastic recycling facilities can significantly mitigate the plastic crisis in developing countries.