Academic public health

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Introduction

Public Health in common with all branches of medicine requires research as the basis for its practice.  It is quite difficult to define what is and isn't Public Health research, since many medical projects will have some Public Health implications.  However, studies which involve large numbers of people or which give results which could apply to large sectors of the population will have more value to Public Health professionals.  These studies will often be carried out by Universities rather than Public Health departments within the NHS itself.

Clinical Trial Service Unit

I was based at the Clinical Trial Service Unit (CTSU) at Oxford University between August 2005 and February 2006.

The CTSU amongst other things organises very large randomised control trials (RCTs) with thousands of participants.  These trials are sometimes termed mega-trials. A larger number of participants usually gives a trial more statistical weight (or 'power'), enabling results to be interpreted more soundly.  I was involved in the SEARCH and ASCEND trials.

SEARCH

SEARCH is investigating the use of high-dose statins for secondary prevention of cardiovascular events in individuals post-MI, and also looks at the use of vitamin B12 and folate in secondary prevention.

The use of vitamin B6 and folate following an acute MI has been questioned after the initial results of the NORVIT trial.  More...

ASCEND

ASCEND is investigating the use of aspirin in primary prevention of cardiovascular events in individuals with diabetes mellitus.  It is also looking at the use of fish oils in primary prevention.

Good clinical practice guidance

Clinical trials in the UK should conform to the International Conference on Harmonisation Good Clinical Practice Guideline E6 - a bit of a mouthful, but often known as ICH GCP or simply GCP.

ICH website | GCP guidelines (pdf, 247kb)

Study ethics

The vast majority of clinical trials will require ethical approval from a research ethics committee (REC).  However, public health service audits and needs assessments, which might involve just interviewing service staff and users, may fall into a grey area regarding whether ethical approval needs to be formally sought.  More information on this can be found on the National Research Ethics Service site and in the paper, below. (Thanks to Dr Paul Wendon-Blixrud for helping find this information.)
National Research Ethics Service guidance
Ethics audit and research: all shades of grey. Wade, DT doi: 10.1136/bmj.330.7489.468 [?] (BMJ, 2005)

Registration of clinical trials

There is currently no obligation for investigators to register clinical trials before conducting them. However pressure is mounting for compulsory registration to try to prevent:

• publication bias (investigators submitting and/or journals only publishing 'interesting' results - usually trials which support the efficacy of a new treatment)
• selective reporting (in which, for example, an 'unwanted' result is suppressed)
• post-hoc changes to study design (for example to change statistical analyses in favour of obtaining a 'positive' result, or to attempt to answer a question for which the original study was not designed). 

To this end a number of organisations have sprung up to allow trialists to voluntarily register their new or ongoing trials, including:

Current Controlled Trials database (International) | Meta-register
IFPMA Clinical Trials portal (International)
National Research Register (UK)
ClinicalTrials.gov (US)
CenterWatch (US)

To fill the gap between a trial ending and formal publication of its results is the Research Findings Register (UK).

Other useful resources

Literature searching

PubMed
Google Scholar
The Cochrane Library

Interpreting the literature

Cochrane Collaboration open learning material  
An excellent introduction to how to objectively assess scientific papers