A single-centre cross-sectional screening study reporting prevalence of undiagnosed conditions via secondary analysis; descriptive in nature with no intervention or comparator arm, limited to hypothesis generation about hidden morbidity in one university population.
This is a methodological critique and position paper proposing caution about interpreting all-cancers-combined associations; it raises questions about epidemiological practice rather than presenting new empirical evidence.
A systematic review of nine heterogeneous studies from four West African countries showing insufficient evidence to characterise regional epidemiology, with no quantitative synthesis possible due to methodological diversity.
Single-center cross-sectional study in Ghana describing maternal health literacy prevalence and associations; no comparator group and observational design limit causal inference and generalizability.
Retrospective descriptive study of a small outbreak (14 cases) with no comparator arm; temporal associations observed but causality cannot be inferred from this design.