Effect of a Health Belief Model Based Digital Nudge Intervention on Breast Cancer Screening

This study aims to evaluate the effect of a multi-component digital nudge intervention based on the Health Belief Model on breast cancer awareness, health beliefs, and screening behaviors among women aged 40-69. The study is a randomized controlled trial. The sample will consist of 64 women aged 40-69. The study will be conducted between December 2026 and December 2027 at the Şükrüpaşa Family Health Center in Erzurum, Turkey. Data will be collected using an Informed Consent Form, the Breast Cancer Awareness Scale, the Health Belief Model Scale for Mammography, and a screening behavior assessment form.

Data Collection: Institutional authorization and ethics committee approval have been obtained. Women who meet the inclusion criteria will be invited to participate in the study following an interview at the center. Verbal and written informed consent will be obtained from volunteers who agree to participate. After providing written informed consent and completing the baseline assessment, participants will be randomly assigned to either the intervention or control group in a 1:1 ratio. All groups will be instructed on how to complete the forms. The planned sample size is 64 participants, with 32 women in each group. Participants in the intervention group will receive two WhatsApp messages per week for six weeks, for a total of 12 messages. Messages will be sent on weekdays between 10:00 a.m. and 5:00 p.m. The intervention will target perceived competence, perceived severity, perceived benefits, perceived barriers, and health motivation. The design principles for the nudge messages will be determined using the nudge principles outlined in the MINDSPACE framework. The control group will continue to receive routine primary care services throughout the study period and will not benefit from the digital nudge intervention.

The Breast Cancer Awareness Scale, the Health Belief Model Scale for Mammography, and a screening behavior assessment form will be administered at baseline and immediately following the six-week intervention. At the three-month follow-up, screening intention and behavior-including whether participants underwent a mammogram-will be assessed. Whether participants underwent a mammogram will be determined based on self-reports and verification through health records.

Randomization:

A total of 64 women who meet the inclusion criteria will be assigned to the intervention and control groups in a 1:1 ratio; each group is planned to consist of 32 participants. To ensure the confidentiality of group assignments, sequentially numbered, opaque, and sealed envelopes will be prepared and securely stored by the researcher. After written informed consent is obtained and the baseline assessment is completed, the next envelope in sequence will be opened to determine the participant's group assignment. Due to the nature of the WhatsApp intervention, it is not possible to blind the participants or the researcher administering the intervention to the group assignment. Group information will be coded during statistical analysis to minimize analysis bias.

Data Analysis Statistical analysis of the data will be conducted using a blinded method. The study data will be coded to conceal group information and forwarded to a statistical expert for analysis. Thus, access to group information by both the researcher and the statistical expert will be restricted during the analysis process, thereby maintaining blinding.

Data analysis will be performed using the SPSS (Statistical Package for the Social Sciences) 21.0 software package. Descriptive statistics (mean, standard deviation, frequency, and percentage) will be used in the evaluation of the data. For comparisons between groups, the t-test or the Mann-Whitney U test will be applied; for comparisons within groups, the paired t-test or the Wilcoxon test will be used. The chi-square test will be used to analyze categorical variables, and when necessary, multivariate analyses (regression analysis) will be performed to evaluate relationships between variables.

Ethical Principles of the Study The study will begin after approval from the Ethics Committee of the Faculty of Medicine at Atatürk University and upon receipt of written permission from the center where the study will be conducted. During data collection, patients will be informed about the study; the principles of "Informed Consent," "Respect for Autonomy," and "Protection of Privacy and Confidentiality" will be adhered to. To protect individual rights, the study will adhere to the Declaration of Helsinki throughout its duration. Patients who are willing to participate and meet the inclusion criteria will be enrolled in the study; their verbal and written consent will be obtained prior to data collection.

Limitations and Generalizability of the Study The study is limited to women who presented to the Erzurum Şükrüpaşa Family Health Center, met the sample selection criteria, and agreed to participate. Therefore, the results can only be generalized to patients with characteristics similar to those of this sample group.