After years of stability, the Office for National Statistics reported that alcohol-specific deaths in 2020 had increased by 19% from 2019, counting 8,974 deaths coded as caused by alcohol misuse, with three in four being from alcoholic liver disease. The national lockdown saw an increase in abstention, but also in heavy drinking. Harm can increase without greater total consumption: the distribution matters, not just the average.
Drinking too much alcohol raises the risks of many diseases, so analysts try to estimate total numbers of deaths attributable to alcohol consumption – they modelled about 19,200 alcohol-related deaths in England in 2019, around four times the direct count of number of alcohol-specific registrations. The method requires many assumptions, such as 11% of breast cancer deaths in women over 75 being due to alcohol, and a major recent change in such attributable fractions cut estimated alcohol-related death figures by around 23%.
People might like a single number to settle an issue but we cannot count everything directly and analysts may need to construct a range of statistics to improve our understanding. Many tens of thousands of deaths every year are attributed to air pollution, but until an inquest in 2020, it was never given as an official cause of an individual death.
Influenza also demonstrates the limitations of counting. Between 2013 and 2020, only around 600 people in England and Wales died with influenza as the direct underlying cause each year. Yet England’s public health agency estimated in 2020 that there were around 15,000 “influenza-attributable deaths” in the 2016-17 season alone. That figure comes from the FluMomo model, which picks out periods with high mortality over a curved seasonal baseline, attributing those deaths to influenza or extreme temperatures. This approach has some weaknesses, including potential overestimation and insufficient corrections for registration delays.
In essence, FluMomo tries to estimate how many fewer deaths would occur if flu were eliminated. That just about happened last winter, contributing to a deficit in non-Covid-19 deaths and our continued distancing behaviour means, once again, flu is running at a very low level. That’s currently about the one bit of good news for the NHS.
• David Spiegelhalter is chair of the Winton Centre for Risk and Evidence Communication at Cambridge. Anthony Masters is statistical ambassador for the Royal Statistical Society
