101 Facts About Ageing #34: Probability Of Death According To Age

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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.

Throughout most of life, the risk of death increases exponentially – very roughly speaking, the annual probability of death increases ten-fold every 20 years between the ages of 30 and 80. During this period, risk of death closely follows what is known as the Gompertz–Makeham law. This law states that risk of death is the sum of two components: one that rises exponentially with age (representing the increased susceptibility of the elderly to most causes of mortality) and one that is not dependant on age (representing death due to environmental factors). In developped countries, the latter component is negligible as the vast majority of deaths are linked to ageing.

Annual risk of death (1 in y) by age and sex:

Annual risk of death by age for males and females in the United Kingdom (2005). Note that each gradation on the y-axis represents a ten-fold increase in mortality, so the mostly straght lines after age 30 means that risk is increasing exponentially.
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This law does not apply at younger ages – the risk of death is higher within the first year of birth at about 1 in 200 in developped countries (give or take, depending on sex). Risk falls sharply within the first few years of life, and is lowest at around the age of 5. The steepest increase in risk occurs throughout adolescence, and risk begins to follow an exponential function by age 30.

Less is known about how risk changes beyond age 80. Some studies suggest that death rates increase at a slower rate in advanced age. Risk of death is higher for males than for females at all ages, however this sex difference is less pronounced at extremes of age. For example in the United Kingdom in 2018, 85-89 year-old males were around 25% more likely to die in any given year than their female counterparts, while risk for 30-34 year old males was about twice as high as for females in the same age range.