PHRC Phase 1 (2005-2011) projects – Cross-cutting projects

D2-06: Tackling inequalities through the social determinants of health: Building the evidence base

Principal investigator

Mark Petticrew, LSHTM


Wanless and other commentators have pointed to the need for better evidence on the effects of interventions to reduce health inequalities. Turning this demand into action however requires (i) identifying what we already know (in terms of the effects of interventions); and (ii) identifying the gaps and using this information to identify priorities for new primary and secondary research.

Aims, methods and contribution

The aim of this project is to identify priorities for new systematic reviews, and for new primary studies evaluating interventions to tackle inequalities in health. The specific questions to be answered are:

  1. What systematic reviews of interventions have been done so far which address the main (non-healthcare) social determinants of health? (e.g., education, housing, transport, income, crime, employment, etc)?
  2. Comparing this to what is already known about the social determinants of health, where are the gaps?
  3. What are the conclusions of these reviews about the effects of interventions, and about the differential impacts of interventions across different social groups?
  4. What are the research recommendations from these reviews?, and
  5. What does recent primary research (that is, primary studies not included in the above systematic reviews) tell us about the most effective means of addressing health inequalities?

We aim to use CRD’s Wider Public Health (WPH) database (a database of systematic reviews of public health and related interventions) as the main source for gathering the evidence. This database however is only current to the end of 2002 and we will build on the WPH work by:

  • Updating and extending the searches from 2000 to mid-2006 to identify new primary research and new systematic reviews which are directly relevant to health inequalities (that is, we will identify more recent evidence on the effectiveness of interventions);
  • Keywording the database to allow it to be searched for evidence of relevance to other PHRC projects, and to the cross-cutting PHRC themes (for example, coding where necessary to identify reviews on obesity, smoking, young people, incentives and risk; inequalities; level of delivery of the intervention (e.g., individual-level, community-level); mode of implementation of the intervention (e.g., NHS, social services, education));
  • Collaborating with the Cochrane/Campbell Equity Group to pool resources and exchange findings with their ongoing “mapping” project, which aims to identify effective interventions to address health inequalities in low and middle income countries, and in high income countries; and
  • Disseminating the findings extensively in appropriate formats.

With respect to dissemination, we will produce the following outputs: (i) a detailed final report (ii) an accompanying summary academic paper, and (iii) a non-academic summary report for wide dissemination and presentation. These papers will act as “position statements” regarding the current state of the evidence regarding priorities for new research, and as pointers towards potentially effective interventions. Given that some of this evidence will have been collected in other countries, we will also assess the generalisability of the findings to other contexts. This work is different to the WPH project in that, unlike WPH, it will seek to include primary research (including qualitative research relevant to the implementation of interventions), and it will use newly-emerging review methods to assess the generalisability of the findings. It will build on existing WPH work by including systematic reviews from 2002 onwards (which are not currently on the WPH database).


In effect we will use PHRC resources and our personal networks and contacts to document systematically the gaps in existing knowledge at the level of systematic reviews and primary research. This will allow us to identify what new research is now required in order to take forward the agenda outlined in the Wanless report. This will be an important contribution to moving public health research from documenting the lack of evidence, toward identifying specifically what research - in particular, what new systematic reviews - needs to be commissioned. This report will also be of value to DH PRP in helping set future priorities for primary and secondary research.

October 2006 - August 2007 (11 months)