#211 The End of Longevity Improvement?
Healthspan
Recent trends suggest a limit to the “never ending” increase in lifespan. Can it really be true?
A Five-Minute Read
We all know that the growth in human lifespan cannot go on forever. The issue is when and how it might end. Teams have looked for the best performing countries in terms of life expectancy. They have pooled them to look for a best-case trend. Over the past one hundred- and fifty years improvements have been three months every year. For every year that we age we have only approached death by nine months.
Over that period successive researchers have claimed that we have reached the end. In 1928 a researcher called Dublin argued that the maximum life expectancy would be 64.5 years. There could be no more improvement. Everyone has been proved wrong. Since I am over 65 I am glad Dublin was wrong. Is that about to change?
A Slowdown in Life Expectancy
Even before COVID the data has been showing a worrying pattern. From 2011 the rate at which life has been extended has slowed. This is across all developed countries. Life expectancy improvement has slowed to almost a crawl. The US fared the worst. Some suggest because of the on-going opioid crisis. The combination of nutrition, public health improvements and medical innovation seems to be running out of steam.
Early improvements came predominantly by reducing child mortality. Medicine helped but nutrition and hygiene had a huge part to play. The advent of vaccination in the middle of the twentieth century had another big impact. There are still improvements in child mortality to make. However the incremental value to life expectancy will be small.
Public heath campaigns, particularly against smoking, started to reduce the deaths in middle and old age. Modern medicine is pushing back many chronic diseases. However, have we reached diminishing returns? There are still huge disparities in life expectancy based on deprivation. The life expectancy of those living in the most deprived areas of the UK is only 73.5 years. This is ten years less than those living in the least deprived areas. It is the life expectancy of Benin or Albania. There are still opportunities but how much of an improvement can they yield?
The chart shows survival curves for different English and Welsh generations. What percentage of a generation are still alive at a given age. The curves are marching across the chart to the right. Death in the early years of life is now very small. Even death in middle age is in decline. The curves are approaching the 100-year-old mark. The latest estimates suggest that a quarter of the current generation may make it. As yet there is no medical way of extending life. Few live to 105 and fewer still to 110. How much scope is there to increase life expectancy?
Worsening Health
An extended life is of little value if those extra years are spent in ill health. Historically longer life brought with it health improvements. Health span grew as well. Recent trends also show a decline in health amongst the younger generations, particularly in the United States. A recent analysis looked at different generations. It used large longitudinal samples in the USA, the UK and 11 Continental European Countries. They looked at the incidence of major chronic diseases and measures of daily activity problems.
It seems that younger generations have higher incidences of chronic diseases at the same age. They are less healthy than older generations at that age. These diseases include cancer, high blood pressure, lung diseases and heart problems. This decline seems to start with the baby boomers. That is the generations from about 1945. The pattern is the same in all countries but is particularly to be found in the USA.
The pattern with disability is more nuanced. They looked at an individuals’ ability to perform six activities of daily living. These included things like bathing and eating. They also had people report on their ability to shop and prepare food, as well lift 10lbs and walk a distance. There were some declines visible but no clear patterns. The researchers suggest that the link between having a chronic disease and disability has been weakened. Modern medicine can treat diseases and control them much better. Younger generations may have higher blood pressure, but it can be controlled.
Too Much of a Good Thing?
Better nutrition means more ability to fight disease. The availability of too much of the wrong kind of food can lead to obesity. There has been a steady decline in “grip strength” in the US and Europe since 1945. This is measured mechanically by squeezing. For a while better nutrition balanced the decline in physical activity. Grip strength was maintained. The amount of manual labour has decreased. Work has increasingly moved inside and to the service sector. We are eating more and using our hands less.
Obesity has grown at the same time as smoking has declined. There was a positive balance as smoking caused many diseases. It has now become negative. The reduction in smoking and secondary smoking reached diminishing returns. The exposome that has been so good for us may now be doing us “harm”.
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