Exploration of the Temporal Trends, Prevalence, and Factors of Acute Respiratory Infection or Diarrhoea: A Cross‐Sectional Analysis of Three National Surveys

Background and Aims Numerous interventions have been targeted to reduce the burden of acute respiratory infection (ARI) and diarrhoea in Bangladesh. Both remain the leading causes of mortality in children under 5 (U5C). We aimed to examine the temporal trends, prevalence, and factors associated with ARI and diarrhoea using three nationally representative surveys. Methods We utilised data from three nationally representative surveys in Bangladesh: the Bangladesh Demographic and Health Survey (BDHS) 2017–2018, BDHS 2022, and the Multiple Indicator Cluster Survey (MICS) 2019. Analyses included the Cochran–Armitage test for trend, a multiple‐adjusted binomial logistic regression model, slope and relative indices of inequality (RII), and the Mantel–Haenszel test with an approximate test of homogeneity of odds ratios. A p ‐value of < 0.05 was considered statistically significant. Results A total of 39,919 U5C were included for ARI and 39,875 U5C for diarrhoea. A downward, monotonic trend was observed in ARI prevalence from 3.1% in 2017–2018 to 1.4% in 2022. In contrast, diarrhoea prevalence increased from 4.9% in 2017–2018 to 6.9% in 2019 and declined to 4.8% in 2022. Male children were associated with higher odds of ARI (aOR: 1.37, 95% CI: 1.04–1.82), and younger children were associated with lower odds of diarrhoea (aOR: 0.97, 95% CI: 0.96–0.98 in 2017–2018). Relative inequality remained significant for both ARI (RII: 2.36 in 2017–2018) and diarrhoea (RII: 1.92 in 2022), indicating disparities across wealth groups. Heterogeneity across survey years was observed only for the association of underweight status and wealth index with diarrhoea. Conclusion ARI prevalence declined by a 2.2‐fold over 5 years, suggesting effectiveness of existing child health strategies, including immunisation and IMCI. Diarrhoea showed no consistent decline. Risk remained higher among male and younger children, with persistent socioeconomic inequalities. Steps should also be taken to consider wealth‐related accessibility and feasibility for future policy‐focused recommendations.