The expectation of human life keeps increasing, but where can it go? – Quartz

Humans live longer in the world. Although there have been obvious ups and downs, life expectancy at birth has globally increased steadily for many years. It has more than doubled in the last two centuries.

This increase was due earlier to the reduction of infant mortality. But since the 1950s, the main factor has been the reduction of mortality among the elderly. In Sweden, for example, where national population data have been collected since the middle of the 16th century and are of very high quality, the maximum lifespan has been increasing for almost 150 years. Increasing lifetimes have been observed in many other countries, particularly in Western Europe, North America and Japan.

This has contributed to a rapid increase in the number of very old people – those who live up to 100, 110, or even more. Geert Adrians-Boomgaard died in 1899, aged 110 years and four months. His record has been beaten by others since. Margaret Ann Neve, the first recognized supercentennial, died in 1903, at the age of 110 years and ten months, and held the record for nearly 23 years. Delina Filkins died in 1928 at the age of 113 years and seven months. She kept the record for a little over 52 years.

The record holder is the French Jeanne Calment, who died on August 4, 1997 at the age of 122 years and five months. Despite the almost exponential increase in the number of super centenarians since the early 1970s, her record is strong, but she will probably not keep it any longer.

Survive after 100 years

Although these life-increasing trends are widespread, they are not obvious. Recent improvements in Danish mortality after a period of stagnation have led to the belief that the lifespan of centenarians may increase in this country. This is quite different from what has been observed recently in Sweden, where there has been some slowdown at the highest ages.

We studied 16,931 centenarians (10,955 Swedes and 5,976 Danish) born between 1870 and 1904 in Denmark and Sweden, neighboring countries with close cultural and historical ties, to determine whether our suspicions were well founded. Although Sweden generally has lower mortality rates than Denmark at most ages, there is no indication that it has increased in recent years. In Denmark, however, it has been observed that the older ones are dying at increasingly higher ages, and the age at which only 6% of centenarians survived has steadily increased over this period.

Denmark and Sweden are similar in many ways, but these trends in life span are very different. The disparity could be due to several causes, which are not easy to disentangle. But we have some ideas.

Health systems

First, the health levels of the two elderly populations are different. Recent studies have shown improvements in health measured by Activities of Daily Living (activities of daily living) – basic tasks required to lead an independent life, such as washing or dressing – among cohorts of centenarian women in Denmark. In Sweden, on the other hand, these trends among the elderly are less optimistic. One study showed that there was no improvement in ADL, with a deterioration in mobility tests, cognition and performance.

The difference between the two health systems, especially in recent times, could also help explain the difference. Spending on public services was reduced in Sweden in the early 1990s, due to a series of economic crises. Health care for the elderly has been affected. For example, in the case of elderly care in hospitals, hospitals have been abandoned for retirement homes and the number of nursing home beds has been reduced. Cost reductions have left some older people at risk, especially those belonging to the most disadvantaged socio-economic groups.

In addition, the two countries have since adopted slightly different paths in the care of the elderly: Sweden tends to target the most vulnerable, while Denmark takes a slightly broader approach. Some studies suggest that the Swedish approach has resulted in some people in need of care not receiving care, with the less favored sections of the older population having greater use of family care, which may be of lower quality.

People who reach advanced ages are a small group and are obviously very durable. Perhaps because of their inherent resilience and particular physiology, they are better able to take advantage of improvements in living conditions and technology.

Our comparative study suggests interesting things for other countries, especially in developing and emerging countries. These results demonstrate that it is possible to further lengthen the life span if improving health at the most advanced ages is possible and if quality care for older people is widely available. Indeed, if this is so, the revolution of human longevity should continue for some time.

This article is republished from The Conversation under a Creative Commons license. Read the original article.