Using genetics to understand the relationship between young people’s health and educational outcomes

Amanda Hughes, Kaitlin H. Wade, Matt Dickson, Frances Rice, Alisha Davies, Neil M. Davies & Laura D. Howe

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Young people with health problems tend to do less well in school than other students, but it has never been clear why. One explanation is that health problems directly damage educational outcomes. In that case, policymakers aiming to raise educational standards might want to focus first on health as a means of improving attainment.

But are there other explanations? What if falling behind in school can affect health, for instance causing depression? Also, many health problems are more common among children from less advantaged backgrounds – for example, from families with fewer financial resources, or whose parents are themselves unwell. These children also tend to do less well in school, for reasons that may have nothing to do with their own health. How do we know if their health, or their circumstances, are affecting attainment?

It is also unclear if health matters equally for education at all points in development, or particularly in certain school years. Establishing how much health does impact learning, when, and through which mechanisms, would better equip policymakers to improve educational outcomes.

Photo by Edvin Johansson on Unsplash

Using genetic data helps us understand causality

Genetic data can help us answer these questions. Crucially, experiences like family financial difficulties, which might influence both a young person’s health and their learning, cannot change their genes. So, if young people genetically inclined to have asthma are more absent from school, or do less well in their GCSEs, that would strongly suggest an impact of asthma itself. Similarly, while falling behind in school might well trigger depression, it cannot change a person’s genetic propensity for depression. So, a connection between genetic propensity for depression and worse educational outcomes supports an impact of depression itself. This approach, of harnessing genetic information to better understand causal processes, is known as Mendelian randomization.

To find out more, we investigated links between

  • health conditions in childhood and adolescence
  • school absence in years 10 & 11
  • and GCSE results.

We used data from 6113 children born in the Bristol area in 1991-1992. All were participants of the Avon Longitudinal Study of Parents and Children (ALSPAC), also known as Children of the 90s. We focused on six different aspects of health: asthma, migraines, body mass index (BMI), and symptoms of depression, of attention-deficit hyperactivity disorder (ADHD), and of autism spectrum disorder (ASD). These conditions, though diverse, have two important things in common: they affect substantial numbers of young people, and they are at least in part influenced by genetics.

Alongside questionnaire data and education records, we also analysed genetic information from participants’ blood samples. From this information, we were able to calculate for each young person a summary score of genetic propensity for experiencing migraines, ADHD, depression, ASD, and for having a higher BMI.

We used these scores to predict the health conditions, rather than relying just on reports from questionnaire data. In this way, we avoided bias due to the impact of the young people’s circumstances, or of their education on their health rather than vice versa.

Even a small increase in school absence predicted worse GCSEs.

We found that, for each extra day per year of school missed in year 10 or 11, a child’s total GCSE points from their best 8 subjects was a bit less than half (0.43) of a grade lower. Higher BMI was related to increased school absence & lower GCSE grades.

Using the genetic approach, we found that young people genetically predisposed towards a higher BMI were more often absent from school, and they did less well in their GCSEs. A standard-deviation increase* in BMI corresponded to 9% more school absence, and GCSEs around 1/3 grade lower in every subject. Together, these results indicate that increased school absence may be one mechanism by which being heavier could negatively impact learning. However, in other analyses, we found a substantial part of the BMI-GCSEs link was not explained by school absence. It’s unclear which other mechanisms are at play here, but work by other researchers has suggested that weight-related bullying, and negative effects of being heavier on young people’s self-esteem, could interfere with learning.

*equivalent to the difference between the median (50th percentile) in population and the 84th percentile of the population

Diagram showing the pathways through which higher BMI could lead to lower GCSEs; either through more schools absence aged 14-16, or other processes such as weight-related bullying.
Our results suggest increased school absence may partly explain impact of higher BMI on educational attainment, but that other processes are also involved.

ADHD was related to lower GCSE grades, but not increased school absence.

In line with previous research, young people genetically predisposed to ADHD did less well in their GCSEs.  Interestingly, they did not have increased school absence, suggesting that ADHD’s impact on learning works mostly through other pathways. This is consistent with previous research highlighting the importance of other factors on the academic attainment of children with ADHD, including expectations of the school environment, teacher views and attitudes, and bullying by peers.

We found little evidence for an impact of asthma, migraines, depression or ASD on school absence or GCSE results

Our genetic analyses found little support for a negative impact of asthma, migraines, depression or ASD on educational attainment. However, we know relatively little about the genetic influences on depression and ASD, especially compared to the genetics of BMI, which we understand much better. This makes genetic associations with depression or ASD difficult to detect. So, our results should not be taken as conclusive evidence that these conditions do not affect learning.

What does this mean for students and teachers?

Our findings provide evidence of a detrimental impact of high BMI and of ADHD symptoms on GCSE attainment, which for BMI was partially mediated by school absence. When students sent home during the pandemic eventually return to school, the impact on their learning will have been enormous.  And while all students will have been affected, our results highlight that young people who are heavier, who have ADHD, or are experiencing other health problems, will likely need extra support.

Further reading

Hughes, A., Wade, K.H., Dickson, M. et al. Common health conditions in childhood and adolescence, school absence, and educational attainment: Mendelian randomization study. npj Sci. Learn. 6, 1 (2021). https://doi.org/10.1038/s41539-020-00080-6

A version of this blog was posted on the journal’s blog site on 21 Jan 2021.

Contact the researchers

Amanda Hughes, Senior Research Associate in Epidemiology: amanda.hughes@bristol.ac.uk

How can researchers engage with policy?

Dr Alisha Davies

Dr Laura Howe

Prof Debbie Lawlor

Dr Lindsey Pike

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Policy engagement is becoming more of a priority in academic life, as emphasis shifts from focusing purely on academic outputs to creating impact from research. Research impact is defined by UKRI as ‘the demonstrable contribution that excellent research makes to society and the economy’.

On 25 June 2019 the IEU held its first Engagers’ Lunch event, which focused on policy engagement. Joined by Dr Alisha Davies, Head of Research from Public Health Wales, Dr Laura Howe, Professor Debbie Lawlor and Dr Lindsey Pike from the IEU facilitated discussion drawing on their experiences – from both sides of the table – of connecting research and policy. Below we summarise advice from our speakers about engaging with policy.

The benefits of engaging with policy & how to do it

  • As an academic you need to consider what your ‘offer’ is. What expertise do you bring? This may be topic specific knowledge or relate to strong academic skills such as critical approaches to complex challenges, novel methods in evaluation, health economics. Recognise where you add value; the remit of academia is to develop robust evidence in response to complex and challenging questions using reliable methods – a gap that those in practice and /or policy cannot fill alone.
  • Find the right people to engage with – who are the decision makers in your area of research? Listen to what is currently important to inform action / policy. Read through local and national strategies in your topic of expertise to understand the wider landscape and where your work might inform, or where you might be able to address some of those key gaps. Academics can also submit evidence to policy (colleagues from the University of Bristol can access PolicyBristol’s policy scan, which lists current opportunities to engage).
  • Be visible and actively engage. Find out what local events are going on in your area related to your research and go along to meet local public health professionals. It’s a good way to meet people, find commonalities and form collaborations.
  • Condense your new research into a short briefing, identify what it adds to the existing evidence base, how does it inform given the wider context.
  • As an academic you will have a network of other research colleagues. Policymakers value being able to draw on this network for information. When providing evidence, don’t just cite your own – objectivity is one of the key advantages of working with academics, and policymakers value your intellectual independence. Your knowledge of the broader evidence base is invaluable.
  • Setting up a research steering group or stakeholder panel can be a great way to develop your relationships and ensure your research is speaking to policy, practice or industry priorities. Key to this is getting the right people involved – this blog post from Fast Track Impact has some useful advice.

The challenges of engaging with policy & how to navigate them

  • Academic and policymaking timescales are different. Policymakers need an answer yesterday while academics may not feel comfortable with providing a definitive response without time for reflection. There’s a need for flexibility on both sides.
  • There are also tensions between the perceived need for certainty and ability to be able to provide it. Policymakers may want ‘an answer’, but the evidence base may not be robust enough to give one. It is more useful to outline what we do and do not know, with a ‘balance of probabilities’ recommendation, than to say ‘more research is needed’.
  • Language can also be a barrier. Academic language is complex and, at times, impenetrable; policymaker documents need to be aimed at an intelligent lay audience, without jargon, and focusing on what matters to them (outlining policy options and the evidence base behind them – not lengthy discussions of statistical methods). Look at Public Health Wales’ publications, for example on digital technology, adverse childhood experiences and resilience, or mass unemployment events, or examples from the NIHR Dissemination Centre or PolicyBristol to get a sense of the language to use.
  • Do you think you have time for networking with non-academic stakeholders? The perception of opportunity costs can be another barrier for academics. While time for networking might not be costed into your grant funding, think of it in the same way as writing a grant application; you can’t guarantee the outcome but the potential reward is significant.
  • There are no guarantees in policy engagement work, and a level of realism is required around what findings from one study can achieve. Policymaking is a complex and messy process; the evidence base is just one factor in decision making. Your recommendations may not be taken up because of politics, resource issues, or other concerns taking priority. Sometimes your relationships will reach honourable dead ends, where you realise that interests, capacity or timescales are not as aligned as you thought. Knowing this before you start is important to avoid feeling disillusioned.
Cartoon showing complexity of policymaking process and comparing it to making sausages
Policymaking is a complex and messy process; the evidence base is just one factor in decision making. Image from Sausages, evidence and policymaking: The role of universities in a post-truth world, Policy Institute at Kings 2017

In summary, the panel concluded that policymakers are interested in academic research as long as their priorities are addressed. While outcomes are not guaranteed, our colleagues at PolicyBristol advise a strategy of ‘engineered serendipity’ – looking for and capitalising on opportunities, being ready to talk about your research in a clear and policy orientated way (why does your research matter and what are the key recommendations?) and aim to build long term and trusting relationships with policymakers.

If you’d be interested in attending a future Engagers’ Lunch, please contact Lindsey Pike.

Further information & resources

PolicyBristol aims to enhance the influence and impact of research from across the University of Bristol on policy and practice at the local, national and international level.

Public Health Wales Research and Evaluation work collaboratively across Public Health Wales and with external academic and partner organisations, and are keen to facilitate research links across Public Health Wales with new national and international partners.

Research impact at the UK Parliament ‘Everything you need to know to engage with UK Parliament as a researcher’

Parliamentary research services across the legislatures include:

  • House of Commons Library: an independent research and information unit. It provides impartial information for Members of Parliament of all parties and their staff.
  • Parliamentary Office of Science and Technology: Parliament’s in-house source of independent, balanced and accessible analysis of public-policy issues related to science and technology.
  • Research and Information Service (RaISe): aims to meet the information needs of the Northern Ireland Assembly Members, their staff and the secretariat in an impartial, objective, timely and non-partisan manner.
  • Scottish Parliament Information Centre (SPICe): the internal parliamentary research service for Members of the Scottish Parliament.
  • Senedd Research: an expert, impartial and confidential research and information service designed to meet the needs of Wales’ National Assembly Members and their staff.