Urban slums in Guinea are characterized by high population density, limited access to basic services such as sanitation and healthcare, and proximity to natural resources like waterways. This context increases vulnerability to environmentally linked diseases. Data were collected through a cross-sectional survey conducted in two major urban slums. A multivariate logistic regression model was employed to assess risk factors associated with the occurrence of diarrheal diseases. Diarrheal disease incidence was significantly higher (p < 0.05) among residents living within 500 meters of waterways compared to those further away, indicating a clear environmental link. The study underscores the importance of integrating environmental health interventions into urban planning and public health strategies in Guinea's slums. Public health initiatives should prioritise improving access to clean water sources and sanitation facilities within slum areas. Policy recommendations include targeted community education programmes on hygiene practices. The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.