Clinical outcomes associated with schistosome infection and alcohol use: A systematic scoping review.

BACKGROUND

Schistosomiasis and alcohol use are major, co-occurring risk factors for liver disease in low and middle-income countries. However, their interactions and shared disease outcomes remain poorly understood.

METHODS

We conducted a scoping review to understand how schistosome infection and alcohol use influence author-defined health outcomes. A systematic search was carried out on 3 March 2025 using the following databases: PubMed (1946 - present), Embase (1974 - present), Web of Science (1964 - present), Global Index Medicus (1901 - present), and Global Health (1973 - present). Quality of studies was assessed descriptively by assessing bias and confounding.

RESULTS

The search yielded 2358 articles, with 21 studies eligible for synthesis. Most studies (76.2%, 16/21) focused on current S. mansoni infection, and the same proportion treated alcohol use as a binary variable. The most frequently reported clinical outcomes were periportal fibrosis (42.9%, 9/21), and biomarkers (19%, 4/21), including serum iron markers. For hepatic outcomes, both synergistic and antagonistic pathways are plausible, while for iron-related outcomes, an antagonistic relationship was supported. Cross-sectional studies were most common (66.7%, 14/21), limiting the ability to make assessments on the temporal relationships between exposures and clinical outcomes. Selection bias was the most frequently reported source of bias (28.6%, 6/21), and only four (19%) studies reported both adjusted and unadjusted analyses, allowing for an assessment of confounding.

CONCLUSIONS

Co-occurring schistosomiasis and alcohol use has been associated with more severe liver pathology, presenting a significant public health concern in endemic areas. Current literature focuses on schistosome-related pathology, where alcohol use acts as a modifying factor. Future research should prioritise longitudinal designs with standardised definitions of alcohol use to better understand interactions between these two exposures for liver outcomes.