Throughout history, life expectancy (LE) has been around 30 years, sometimes lower, e.g. with the adoption of agriculture, plague, or cramming the new industrial working class into slums (described in Engels’ Condition of the Working Class in England; he called their accelerated deaths “social murder”). Marx predicted increasing immiseration of the working class relative to the ruling class so it is doubtful whether he could have predicted what would actually happen to all classes, LE more than doubling in under 200 years, an average extra 20,000 days of life.
A sharp change
Though the rich usually lived longer, average LE remained constant until about 1720. Then the aristocracy’s LE started increasing, followed from about 1850 by everyone else. Since then, LE in Britain has more than doubled to over 80. The book* Extra Life: A Short History of Living Longer (Stephen Johnson) and the BBC/PBS documentary** of the same name (presenters David Olusoga, Stephen Johnson) show how improvements in our lives have caused this astounding development.
This increase is due not to evolution — the oldest in our hunter-gatherer ancestors were of a similar age to our present-day elders (and fitter) — but more to reducing infant (and only secondarily adult) mortality. The innovations extending LE can be summarised as improved nutrition, public health measures, and medical interventions.
Johnson estimates lives saved by such changes in terms of millions, hundreds of millions and billions.
Innovations
The innovations which saved “millions” include AIDS cocktails (combinations of anti-HIV drugs), anaesthesia, angioplasty (unblocking coronary arteries), antimalarial drugs, CPR, insulin, kidney dialysis, oral rehydration therapy (ORT: to treat diarrhoea, a major child killer), pacemakers, radiology, refrigeration, and seatbelts. The “hundreds of millions” innovations include antibiotics, bifurcated needles (simplifying smallpox vaccination), blood transfusions, drinking water chlorination, and milk pasteurisation. And the “billions” comprise artificial fertilisers, toilets and sewers, and vaccines.
Programme 1 in the TV series deals with vaccination, starting with smallpox. A scourge for at least 3,000 years, smallpox had 30% mortality, higher among babies, with survivors “pockmarked” or disabled. In the 20th century, smallpox killed four times as many as died in both world wars..
The last smallpox death occurred in 1978. The last “wild” case, in 1977, was a Somali who had refused the vaccine. He survived. Smallpox was eradicated by global cooperation; following that, LE in low-income countries rose from 42 to over 60. Vaccination for many diseases has saved billions of lives.
Effective medical drugs contributed much to increasing LE. Previously, as programme 2 shows, many medical “cures” comprised actual poisons. Johnson and Olusoga (J&O) cite Duffield’s Concentrated Medicinal Fluid Extract, containing belladonna, arsenic and mercury. Others contained lead, antimony, radium (!), benzene, strychnine, or some combination. While these likely lowered LE in patients, effective drugs such as penicillin probably increased it by about 30 years.
Before World War 2, bacterial infections were the most common cause of deaths (e.g. of my grandfather, aged 30, and my mother-in-law’s two toddler siblings) but are now largely survivable, thanks to the discovery of penicillin, the international wartime collaboration which helped make it widely available, and other antibiotics.
J&O retell the 1941 story of policeman Albert Alexander, dying from an infection caused by a scratch from a rose thorn. Temporarily recovering with penicillin treatment, he relapsed and died when the then-scarce drug ran out.
Later, drugs that inhibit viruses were developed, including “cocktails” of antiretroviral drugs that have prolonged the lives of millions of people with HIV. In 2020, the RECOVERY Trial found that dexamethasone, a cheap anti-inflammatory, increased survival from serious Covid infections, so far saving a million lives worldwide (though hydroxychloroquine and ivermectin have no effect).
These breakthroughs are from publicly funded initiatives: as J&O highlight, antibacterial and antiviral R&D require large investments with no guaranteed return. Now, basic scientists are using AI to bypass drug companies to discover antibiotics to replace those against which resistance has developed.
The role of data
One crucial innovation J&O highlight is the use of data in epidemiology. Indeed, without data, we would have no idea of LEs and what people die of. This branch of medicine was virtually invented by Dr John Snow, who analysed the pattern of cholera cases in Soho in 1854, identifying the Broad Street pump, with sewage-contaminated drinking water, as their origin. Cholera in the 19th century could kill within two days by diarrhoeal dehydration (death rates nowadays are far lower, thanks to ORT). Evidence of its spread by contaminated drinking water encouraged the building of the still-operational Victorian sewer system.
Despite that, a further outbreak of cholera occurred in East London in 1866, killing over 5,500: in a triumph of data analysis, medical statistician William Farr used information about cholera cases to identify the East London Waterworks Co as the source, with a specific reservoir polluted by waste from a faulty WC in a house whose occupants had cholera.
Recently, epidemiological data have revealed health inequalities, including significant differences in survival from Covid amongst white, black and Asian communities in East London. This is not genetic but environmental: living conditions, types and conditions of work, the effects of racism. This disparity is no surprise: 125 years ago, black sociologist and socialist W E B Du Bois meticulously collected data on deprivation among the black population of Philadelphia, whose child mortality was twice that of whites.
Other examples include the scandal of lead from petrol affecting poor urban children’s development. Herbert Needleman measured lead in children’s baby teeth in the 1970s, linking this to cognitive impairment. It took decades to phase out leaded petrol, against resistance from the lead industry.
Hygiene
Lastly, J&O look at the effects of hygiene behaviour. In the 1800s, with filthy streets, no running water, and no knowledge of germs, the importance of hygiene was not realised. One pioneer, Ignaz Semmelweiss, found that, of two wards in the 1840s Vienna maternity hospital, the doctor-run one had a far higher death rate from puerperal fever than the midwife-run one. He observed doctors going from dissections in the pathology laboratory to the labour ward and deduced they were passing something on their hands.
Hand-washing reduced deaths by 90% but the medical establishment rejected Semmelweiss’s proposal to make this routine. He was sacked.
Florence Nightingale analysed deaths of soldiers in Crimean War field hospitals, showing that most died from infections. Increased sanitary precautions (such as washing hands) reduced deaths by 99%. This evidence for the germ theory encouraged hygienic practices, adopted in surgery by the 1890s and then spreading to the general population. More frequent washing helped reduce infections, increasing LE by 20 years in the early 20th century. Soap destroys bacteria and viruses, explaining the reduction in many infections with the increase in hand-washing during the Covid pandemic.
LE has not always risen: there have been dips due to world wars, the 1918 influenza pandemic and the Covid pandemic, but overall we have gained some 20,000 days over our fairly recent ancestors. This book and documentary series show how.
*https://www.penguinrandomhouse.com/books/594501/extra-life-by-steven-johnson/ [£20 in UK]
**https://www.bbc.co.uk/iplayer/episodes/m000w6s7/extra-life-a-short-history-of-living-longer [available for 4 months]
Random Walk in Science 