Framing action to reduce health inequalities: what is argued for through use of the ‘upstream–downstream’ metaphor?

BACKGROUND: Public health insights struggle to compete with dominant ideas which frame health inequalities as a problem of individual behaviour. There is consequently a need to critically reflect upon and question the effectiveness of different strategies for framing and communicating key insights. Taking the example of the 'upstream-downstream' metaphor, this literature review contributes to a necessary first step by asking what exactly is being argued for through its use. METHODS: An iterative search strategy was used to identify peer-reviewed articles which could contribute to the review question. A discourse analysis framework informed data extraction and synthesis of 24 articles. Articles were subsequently categorized into groups which reflected the different uses of the metaphor identified. RESULTS: All authors used the metaphor to promote a particular causal understanding of health inequalities, leading some to recommend policies and programmes, and others to focus on implementation processes. This seemingly simple metaphor has evolved beyond differentiating 'upstream' from 'downstream' determinants, to communicate an ambitious politically engaged agenda for change. CONCLUSIONS: The metaphor is not without its critics and in light of the complexity of the arguments encapsulated in its use, work is needed to establish if it can, and does, resonate as intended with wider audiences.