101 Facts About Ageing #7: Human Lifespans Are Becoming More Similar

As Daniel Patrick Moynihan, an American sociologist, politician, and diplomat once said: “Everyone is entitled to his own opinion, but not his own facts”. And we wholeheartedly agree. A shared set of facts is the first step to building a better world with longevity for all. In that spirit, we are creating a series that covers 101 indisputable facts about ageing, health and longevity.

As discussed in fact #5, humans are living longer on average, largely because fewer die young. However, there is no concrete evidence that the maximum age to which humans can live is increasing. This means that the ages at which people are dying are growing closer together – this is called compression of mortality, and is easily visualised as the ‘death spike’ shown in the graph below.

The graph compares the number of deaths at a given age for women in the US in 1933 vs 2014. It can be seen that fewer people now die below the age of 80 – instead, more people now die above the age of 80, but the number of people living to 110 has not changed significantly. Consequently, 50% of all deaths now occur within 16.3 years of each other, compared with a span of 26.3 years in 1933.

The relationship between increasing average lifespan and converging ages of death is consistently found across different populations and time periods. This includes extreme cases such as in Japanese women (with a life expectancy of 87) and traditional hunter-gatherer societies (with life expectancies of around 40).