Making the most out of cohort studies
Here in the UK we have lots of long-term studies following the health of a particular group of people. These cohort studies are goldmines of information for health researchers. Here Professor Jill Pell, Director of the Institute of Health and Wellbeing at the University of Glasgow, reflects on why our new Cohort Directory will make life easier for researchers – and make the most of this valuable information.
Cohort studies are a fantastic resource but we’re not getting the best out of many of them at the moment. That’s why, here at the MRC, we’ve developed the Cohort Directory to increase the awareness and use of these important resources.
These population cohort studies recruit very large numbers of people from the general population and collect lots of information – using questionnaires, measurements and biological samples – about their health at that particular time. They then follow them up periodically to find out who develops health problems.
For population health scientists, like me, they are the gold standard method for determining what causes disease – the essential first step in preventing it.
The huge value of cohort studies is, in part, due to their versatility. You can study lots of different risk factors and outcomes in the same group of people, and the range of risk factors is wide – lifestyle, environment and genes. You can also tell the order in which things occur, so you can differentiate between the causes of disease and the effects of disease.
At the MRC, we recently completed a review of all of the large, population cohort studies we fund. One of the most heartening findings was the huge support from the general public. Amazingly, 1 in 30 of the UK general public are currently participating in a cohort study.
These people have given huge amounts of their time to support research, and cohort studies are very expensive to set up and run. Therefore, we should make sure that cohort studies are accessible to a large number of researchers so that we can squeeze as much useful information as possible out of them.
Some cohort studies have been exemplary. ALSPAC (also known as Children of the 90s) and UK Biobank have championed the ideal of open access (while ensuring they protect the confidentiality of their participants).
I have personal experience of using data from both cohorts to undertake research that would not otherwise have been possible. A quick glance at the ALSPAC website clearly demonstrates how open access can increase the value for money of cohort studies – with 171 research studies published using ALSPAC data in 2014 alone.
Unfortunately not all cohort studies are as widely known or used. Therefore, we decided to tackle this by developing the Cohort Directory. The website provides a single information point for finding all the large, general population cohorts in the UK and identifying which might be relevant to answer specific research questions.
In addition to a brief description of the cohort, researchers can combine search terms to identify which cohorts provide information on, for example, smoking, adiposity and ethnic group in women in a specified age range. It then provides contact details so that researchers can contact relevant cohorts directly to find out more and request access to the data.
As a researcher, I think this resource will be invaluable in improving awareness and use of these valuable resources, and I encourage the rest of the research community to take full advantage of this exciting development.