By Colin Angus
The World Health Organization recently published their Global Health Estimates for 2019 with a news story that led on the fact that 7 of the top 10 causes of death worldwide are from so-called Non-Communicable Diseases (NCDs), diseases that, unlike infectious diseases, cannot be passed on from one person to the next. In recent decades huge progress has been made globally to reduce the impact of infectious diseases such as HIV, tuberculosis and malaria, but at the same time deaths from NCDs such as cancer, heart disease and diabetes have increased. In a sense this is inevitable, since we all have to die from something, but many of these deaths are premature and thus associated with a significant loss of potential years of life. Many NCD deaths can also be linked directly to behavioural risk factors such as smoking, alcohol consumption, or poor diet, or to wider social risk factors such as poverty and poor housing. As a result, there is huge potential for action on NCDs and their risk factors to improve global health.
For many people, however, their first reaction to the WHO’s headline will have been to think ‘But what about COVID?’. The best available data is that over 1.6million lives have been lost around the world to COVID-19 itself, and that is without considering the knock-on effects from overwhelmed healthcare systems and other indirect effects. Most studies which have looked at the mortality impact of the pandemic across multiple countries have found that the UK is among the worst-affected countries in the world. So, given these facts, is it time for all of us working on NCDs to retrain as infectious disease specialists? How does the burden of COVID-19 in the UK compare to the ongoing burden of NCDs?
To answer that question we can turn to the latest estimates for the Global Burden of Disease Study, led by the Institute for Health Metrics and Evaluation at the University of Washington. This study produces estimates of the number of deaths, by cause, for every country in the world, with the latest figures taking us up to 2019. Data is available for quite detailed causes of death, but let us just focus on three broad categories: NCDs, infectious diseases and injuries. For 2019, these numbers for the UK look like this:
This is a pretty striking distinction: 554,000 deaths from NCDs (89% of the total) compared to 47,000 deaths from infectious diseases (8%) and 21,000 injury deaths (3%). It isn’t hard to see from these numbers why our SIPHER Consortium was set up with a focus on NCDs. But how do these numbers compare to the death toll of the pandemic?
In the UK, conservative estimates suggest that there have been over 80,000 more deaths in 2020 compared to previous years. Using this estimate along with official figures from the Office for National Statistics, which show that 73,125 of these were confirmed as having been directly from COVID-19, we can make this comparison:
This illustrates that, even with the huge mortality impact from COVID in 2020, the total number of deaths is still dwarfed by the annual NCD burden in the UK. Even if all of the excess mortality in 2020 was due to COVID, and assuming that the ‘normal’ deaths in 2020 will look similar to 2019, infectious diseases will still only account for 18% of all deaths compared to 79% for NCDs.
Ah, but wait, some of you may be saying, maybe the people who died from COVID-19 would otherwise have died later in 2020 from an NCD, meaning that we’d expect infectious diseases to represent a larger proportion of deaths this year than this graph would suggest. That’s a reasonable hypothesis, but it just isn’t borne out by the data. Public Health England have done some excellent work to estimate how the number of deaths from non-COVID causes in England this year compares to what we would have expected to see if the pandemic hadn’t struck.
This shows that the tiny green sliver of ‘other cause’ deaths in the figure above are actual hiding some very interesting patterns. Deaths from many NCD causes are much higher than we would otherwise have expected, perhaps as a result of the huge disruption to the health service we have seen in 2020, while deaths from communicable diseases are much lower than we would have expected. The reason for this isn’t hard to figure out – all of the measures that we are taking against COVID-19 (social distancing, mask wearing, hand washing etc.) are also effective at limiting the spread of other communicable diseases. This is why the southern hemisphere saw almost no flu season this year.
Where does this leave us? Well, there is no doubt that the health impact of COVID-19 is unprecedented in scale and the pandemic requires continued collective action to try and limit further harm, at least until a vaccine has been fully rolled out and is proven to prevent serious illness and long-term COVID-related consequences in those who are protected. But, it is important that we do not lose sight of the fact that even in 2020, roughly four times as many people will die of NCDs than COVID-19 in the UK, and there is no NCD vaccination programme for us to pin our hopes on. Only concerted cross-sectoral policy efforts that prioritise health and wellbeing in all policies will be able to address the social, economic and individual burden that NCDs place on society.