Factors Associated with Positive Fecal Immunochemical Test Results for Colorectal Cancer Screening among At-Risk Populations in Southern Thailand: A Cross-Sectional Analytic Study

Colorectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality globally. Early detection through Fecal Immunochemical Test (FIT) screening is essential, particularly among at-risk populations. However, evidence linking dietary consumption behavior to FIT test outcomes remains limited in Thailand, especially in the southern region. This study aimed to determine the prevalence of positive FIT results and to examine the association between dietary consumption behavior and sociodemographic factors with positive FIT results among at-risk individuals in Southern Thailand. A cross-sectional analytic study was conducted among participants aged 50-70 years who underwent FIT screening in primary healthcare units in Nakhon Si Thammarat Province between October 2023 and August 2024. Totally, 382 participants were included, 191 cases with positive- and 191 controls with negative-FIT results. The case-control ratio was 1:1. Data were collected using structured questionnaires assessing demographic characteristics, health risk factors, and dietary consumption behaviors. Crude and multivariate logistic regression analyses were performed to identify factors associated with a positive FIT result. The prevalence of positive FIT results was 13.77% (95% CI: 12.04-15.66). Multivariate analysis showed low dietary consumption behavior was prevalent (83.77%), it was not significantly associated with FIT positivity (AOR = 1.10, 95%CI: 0.71-1.68), after adjusting for confounders. However, lower education level (AOR = 0.50, 95%CI: 0.32-0.78), agricultural occupation (AOR = 0.45, 95%CI: 0.25-0.82), and monthly income between 3,000-8,000 Baht (AOR = 2.11, 95%CI: 1.27-3.49) were significantly associated with a positive FIT result. Education, occupation, and income were significantly associated with positive FIT results. Targeted education and risk-reduction strategies are recommended to improve CRC screening outcomes in at-risk populations.