After a century of progress, our lifes of life strike a wall

The researchers used six different methods for their calculations and came to the same conclusion.

The future trajectory of life expectancy remains a subject of considerable debate among scientists. At the beginning of the 20th century, life expectancy increased at a remarkable pace: individuals born in 1900 lived on average 62 years, while those born in 1938 reached around 80.

In a study recently published in the Proceedings of the National Academy of Sciences (PNAS), José Andrade (Max Planck Institute for Demographic Research (MPIDR)), Carlo Giovanni Camarda (National Institute for Demographic Studies (INED)), and Héctor Pifarré I Arolas (University of Wisconsin-Madison) examined that people born between 1939 and 2000 undergo compared to life. Their analysis focused on 23 countries with high income with low mortality rates.

“If today’s generations followed the same trend as that observed during the first half of the 20th century, a person born in 1980, for example, could expect to live at 100,” explains José Andrade, principal of the study and researcher at Mpidr. “We have studied if the rhythm of the gains of life expectancy slows the current cohorts.” To explore this, the researchers projected the life expectancy of these groups using data from the human mortality database (HMD). They applied six distinct mortality forecasting methods – statistical tools that use historical and current mortality models to predict future lifespan – to estimate how life expectancy can evolve.

“To ensure solid results, we do not only use a method, but several: some well -established, including the United Nations global prospects, and others representing the point of mortality forecasts,” said Andrade.

Researchers applied two main strategies to develop cohort mortality profiles:

• The methods based on the period included approaches such as Lee-Carter, smooth and limited mortality, the analysis of composition data and the world’s global prospects (2024).
• Cohort-based methods included the Linear Lee-Carter model and the segmented transformation of cohort of death to death.

Small room for improvement

“All forecasting methods show that life expectancy for people born between 1939 and 2000 increased more slowly than in the past. Depending on the method used, the rate slows down between 37 and 52%, ”explains the researcher. “We plan that born in 1980 will not live to be 100 on average, and none of the cohorts in our study will take this step. This drop is largely due to the fact that the overvoltages spent in longevity were motivated by remarkable improvements in very young ages survival. ”

At the beginning of the 20th century, infant mortality decreased sharply due to the progress of medicine and improvements in living conditions, which fueled the spectacular increase in life expectancy. Today, however, mortality in these young age groups is already so weak that additional gains are minimal. The team’s projections suggest that reductions in mortality among older populations will not progress quickly enough to compensate for the slower rate of improvement.

From 1900 to 1938, life expectancy increased by about five and a half months with each new generation. For those born between 1939 and 2000, the increase slowed about two and a half to three and a half months per generation, according to the forecasting method.

Andrade, Camarda and Pifarré I Arolas consider this result as very robust. They argue that even if survival in adults and the elderly had to improve the rate provided in forecasts twice, the resulting gains in life expectancy would always be below those obtained in the first half of the 20th century.

Forecasts are predictions, not certainties

Mortality forecasts can never be certain because the future can take place unexpectedly. Events such as pandemics, new medical treatments or societal changes can considerably affect real life expectancy. Therefore, life expectancy may not align with the planned trends. Consequently, forecasts must always be considered as educated estimates. It is important to note that these forecasts apply to populations, not to individuals.

Why is research on life expectancy so important?

Changes in life expectancy affect social cohesion and personal life planning. Governments must adapt health systems, pension planning and social policies. At the same time, life expectancy influences personal decisions concerning savings, retirement and long -term planning. If life expectancy increases more slowly, governments and individuals may need to recalibrate their expectations for the future.

Reference: Proceedings of the National Academy of Sciences.
DOI: 10.1073 / PNAS.2519179122

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