Longevity Briefs: Is Each Generation Ageing Faster Than The Last?

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Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

When it comes to aspects of human health, we generally expect things to improve as medical technology advances, but evidence clearly shows that this is not the case. Life expectancy had stopped improving or decreased in some countries even prior to the COVID-19 pandemic. And while life expectancy has increased greatly over the past 100 years, there’s little evidence that health expectancy (how long you can expect to live free of age related diseases) has changed, suggesting that we are not ageing any more slowly. In fact, there’s some evidence that things may even be getting worse, such as this study published in preprint.

The discovery:

Analysing data from studies totalling around 115,000 50+ year-old participants from across Europe and the United states, researchers discovered a concerning trend. Successive birth cohorts were increasingly likely to have been diagnosed with a chronic age-related disease at a given age. For example, compared to people born during World War II, those born between 1955 and 1959 were around 25% more likely to have heart problems and 50% more likely to have diabetes at a given age. Successive generations also had a higher prevalence of obesity and severe disability. Since these comparisons were age-adjusted, they cannot be explained by people living longer.

Risk of diagnosis of different age-related diseases in different regions (according to the key) at a given age. The risk ratio is relative to people born in the years 1936-1945, who have a risk ratio of 1. For example, a risk ratio of 0.5 means half the number of diagnoses as in people born 1936-1945, while a risk ratio of 2 would mean twice the number of diagnoses.
*Generational differences in physical health and disability in the United States and Europe*
*https://doi.org/10.1101%2F2024.01.16.24301347*

The extent to which the health of successive generations worsened varied by region, with Southern Europe suffering the steepest rise in age-related diseases, while the United States often had the lowest increase. Note that this doesn’t mean that people in the United States get less age-related disease (indeed the average age at diagnosis is lower in the US than in most of Europe for many of these diseases).

The implications:

This study suggests that younger generations are getting age-related diseases earlier and are more likely to be frail at a given age, which could be an indication that they are ageing more rapidly. Why? If we really are getting more age-related diseases than we were 80 years ago, there’s clearly something deeply wrong with the environment we’ve created for ourselves. The type of diet that is encouraged by food industrialisation, the facilitation of a sedentary lifestyle and the consequent rise in obesity prevalence could be to blame. We know that there is a relationship between obesity, diabetes and accelerated ageing.

It’s important to consider that this study looked at diagnoses of age-related diseases. We have become better at diagnosing diseases early, partly because people are more aware of and more likely to report symptoms early on. This is quite likely to partly explain why later generations seem to get age-related diseases at an earlier age, but the authors argue this isn’t the whole story. Objective measurements like blood pressure, cholesterol and HbA1c (a marker of prolonged high blood sugar) also appear to be higher at a younger ages in more recent generations. This is a worrying observation, as with the global population growing increasingly old due to declining birth rates, the last thing we need is for people to be getting ill earlier in life as well.