Determinants of infant formula feeding among mothers in Sorong City, Southwest Papua, Indonesia: A cross-sectional analytical study

Background: Infant formula use is increasing in Indonesia despite ongoing breastfeeding promotion campaigns. Understanding the socio-economic, cultural, and informational factors influencing this decision is essential for designing effective interventions, particularly in rapidly urbanizing regions such as Sorong City, Southwest Papua. Methods: We conducted a community-based cross-sectional analytical study between March and June 2024 among 180 mothers of infants aged 0–12 months in Sorong City, selected through stratified random sampling. Data were collected using a pre-tested, structured questionnaire covering socio-demographic, cultural, economic, and information-seeking variables. Descriptive statistics summarized participant characteristics, while multivariable logistic regression identified predictors of formula use. Adjusted odds ratios (AOR) with 95% confidence intervals (CI) were reported. Ethical approval was obtained from the relevant institutional review board, and informed consent was secured from all participants. Results: Of the 180 mothers surveyed, 46.7% reported current use of infant formula. In multivariable analysis, two factors emerged as significant predictors: use of digital media for nutrition information (AOR = 2.30; 95% CI: 1.13–4.68; p = 0.022) and greater household microeconomic capacity (AOR = 2.05; 95% CI: 1.05–4.02; p = 0.035). Most socio-demographic, cultural, health, and product-related factors were not statistically significant, though nutrition-related cultural beliefs approached significance (p = 0.054). Conclusion: In Sorong City, economic capacity and access to digital health information appear to exert greater influence on formula feeding decisions than traditional socio-cultural factors. Public health strategies should integrate digital engagement, combine economic empowerment with breastfeeding support, and strengthen the regulation of online marketing for breast-milk substitutes