From genome to exposome: universal newborn genetic screening is the wrong focus if we want to improve population health

It is a consistent failing of governments to be seduced by the lure of a new health technology which they claim will transform health services and improve health. Recently, the Secretary of State for Health and Social Care, Wes Streeting, announced a programme whereby every newborn in England will undergo whole genome sequencing. “The revolution in medical science means that we can transform the NHS over the coming decade, from a service which diagnoses and treats ill health to one that predicts and prevents it,” he said.

As with all new policies and technologies we need to ask what is the evidence to demonstrate that this programme will yield such benefits and what are the negative consequences and costs? Given that a key objective of the programme is to prevent illness, it also begs the question as to why the government does not focus its attention and resources more on modifying more important, easily identifiable, risk factors which affect health throughout the life course?

The policy of universal genetic screening at birth is an example of population medical screening by which apparently healthy people are tested to identify those who may have an increased chance of developing a disease or condition. They are then offered more information, further tests, or treatment as appropriate.

History is littered with examples of new technologies purporting to detect disease or the risk of future disease, and then being used to screen parts of the population, only to find later that the benefits were overstated, the associated harms under recognised, and the costs unjustified. That is why strict criteria were developed by Wilson and Jungner to be considered before introducing any screening programme. It is also why rigorous research is needed to inform such decisions.1 In the UK, the National Screening Committee makes recommendations to the government regarding screening programmes, based on rigorous appraisal against Wilson and Jungner’s criteria.2 This has protected the public from being subjected to many unfounded and potentially harmful testing schemes and saved the NHS time and resources.

While these criteria still form the bedrock of decision making on when to rollout population based screening, there is discussion as to how these need to evolve given the development of newborn genetic screening and the associated evaluative research needed.3 Crucial evidence will come from the Genomics England Generation Study, which aims to screen 100 000 newborn babies for over 200 genetic conditions between 2024 and 2027.4 However, we are some way off having sufficient evidence to assess the short and long term benefits and harms experienced by babies who are screened, as well as the cost-effectiveness and broader societal impact of such programmes. So, the recent announcement that newborn genome screening will be rolled out within a decade is premature and potentially undermines the UK’s rigorous screening governance arrangements.

It is the harms in particular that should concern us. Population genetic screening with its inherent false positives, false negatives, and unpredictable clinical consequences of mutations has the potential to generate a lifetime of anxiety for parents and their children. We run the risk of turning future generations into patients from the moment they are born, with overdiagnosis and overtreatment, as well as profound implications for how these data will be used by third parties such as life insurance companies.5

More worrying though is the obsessive focus on technology where there are important modifiable social determinants or risk factors which newborns are exposed to at individual and a community level.

Deprivation, education, housing, urban environment, air pollution, food systems, smoking, alcohol, and social support are well established influences on physical and mental health. These are the upstream “exposome” factors that are driving the major downstream pressures that health services are facing from obesity, mental ill-health, and chronic multimorbidity. If these were tackled with the same passion as people have for new advances in medical science it would have a much more profound and long-lasting effect on their health throughout the life course, and crucially, it would help tackle inequalities.

The 20 year gap in life expectancy between the richest and poorest in society is not explained by our genes.6 Research consistently shows that wider environmental and social determinants have a greater influence on health than genetic factors. For example, recent evidence from 500 000 UK Biobank participants found that environmental and lifestyle factors explained about 17% of the variation in all cause mortality compared to less than 2% from our genetic predisposition.7 The doubling of life expectancy in the UK over the last 200 years illustrates the dramatic effects of changes in our exposome while our genome has remained stable.

If the NHS is serious about providing predictive scores for health trajectories then a simpler and more honest method would be to harness existing demographic, government, and NHS data to estimate an exposome score for newborns (and their parents). The distribution and trends in these scores should be published to help drive and evaluate local and national public health policy and used to hold governments to account.

Our genome combines the promise of new technology with the hegemony of individualism. Our exposome in contrast highlights the lived experience of complex, whole systems and unequal exposures. While politicians cannot alter our genetic code they can tackle systemic societal inequalities.