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Head To Head

Should action take priority over further research on public health?

BMJ 2018; 360 doi: (Published 01 February 2018) Cite this as: BMJ 2018;360:k292
  1. Simon Capewell, professor1,
  2. Paul Cairney, professor2,
  3. Aileen Clarke, professor of public health and health services research3
  1. 1Public Health and Policy, Institute of Psychology Health and Society, University of Liverpool, Liverpool, UK
  2. 2University of Stirling, Stirling, UK
  3. 3Warwick Medical School, Warwick, UK
  4. Correspondence to: S Capewell, A Clarke

We have evidence on which to act, and inaction costs lives, argue Simon Capewell and Paul Cairney. But Aileen Clarke says our understanding of the human behaviour that leads to unhealthy choices is still lacking

Yes— Simon Capewell, Paul Cairney

Centuries of improvements in public health reflect actions not excuses. There are important reasons to act now, rather than wait for perfect evidence.

Firstly, we know what causes most avoidable disease and deaths: poverty, poor diet, tobacco, and alcohol.1 And we know which evidence based interventions work. Therefore, to wait for yet more evidence is ethically unacceptable. Further delay will perpetuate the current huge and unequal burden of harm. Policy makers and clinicians need to act now, on a “balance of probabilities,” not wait for a mythical evidence “magic bullet” to remove all doubt.

Politics, evidence, and ambiguity

A focus on “insufficient evidence” often betrays a simplistic view of policy making, that evidence is used merely to reduce uncertainty. Politics is actually about using evidence to reduce ambiguity. Evidence is important, but policy change requires a powerful story and the ability to exploit windows of opportunity.2 Effective political actors use evidence to draw attention to urgent problems, encourage policy makers to understand them primarily as epidemics, and generate demand for evidence based public health solutions—for example, the recent smoke-free legislation and levy on sugary drinks.

A delayed response to evidence can be damaging. For example, a cumulative meta-analysis published in 1972 provided ample evidence that thrombolysis reduced deaths from heart attack by about 25%.3 However, repeated failure to consider this substantial evidence, compounded by medical conservatism, meant that thrombolysis was not widely used until 20 years later. Many patients were thus denied effective treatment,4 likely resulting in about 50 000 avoidable deaths over two decades in the United States. Systematic reviews alone may not be …

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