Abstract
<title>Abstract</title> <p> Background Household environmental conditions are important determinants of childhood health, particularly in low-resource settings where inadequate water, sanitation, and hygiene increase the risk of infectious diseases. In Somalia, fever, cough, and diarrhea remain among the leading causes of morbidity among children under five years of age. However, evidence on the association between household environmental risk and the co-occurrence of these illnesses is limited. This study assessed the association between household environmental risk and co-occurring fever, cough, and diarrhea among under-five children in Somalia. Methods A secondary analysis was conducted using data from the 2020 Somali Health and Demographic Survey (SHDS). A total of 15,967 under-five children were included. A household environmental risk index was constructed using household environmental indicators, including drinking water source, sanitation facilities, time to obtain water, and electricity access. The outcome was co-occurring childhood illness, defined as the presence of two or more of the following symptoms within the two weeks preceding the survey: fever, cough, and diarrhea. Survey-weighted descriptive statistics summarized participant characteristics, and multivariable survey-weighted logistic regression was used to identify factors associated with co-occurring illness. Adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were reported. Results Overall, 723 (4.5%) children experienced co-occurring fever, cough, and diarrhea during the two weeks preceding the survey. Approximately 60.8% of households were classified as having high household environmental risk. After adjustment for potential confounders, children living in households with high environmental risk had significantly higher odds of co-occurring illness than those in lower-risk households (AOR = 1.53, 95% CI: 1.09–2.15; <italic>p</italic> = 0.013). Older child age, rural residence, higher household wealth, and residence in Togdheer and Middle Shabelle were also independently associated with the outcome. Conclusions High household environmental risk is associated with increased odds of co-occurring fever, cough, and diarrhea among under-five children in Somalia. Strengthening interventions that improve household environmental conditions, including access to safe drinking water, improved sanitation, and basic household infrastructure, may reduce the burden of multiple childhood illnesses. These findings support integrated environmental health strategies as part of child survival programs in Somalia. </p>