Five score years will be norm as 'old old' multiply

Life expectancy at birth could reach 100 in the next 60 years if present trends continue, researchers report.

A study of the growth in longevity in Switzerland has revealed that more people live to be 100 in Europe's most peaceable nation than anywhere else on the continent.

In 2000, there were 796 people aged 100 or older in Switzerland and the number has doubled every decade since 1950.

World-wide, life expectancy has more than doubled over the past 200 years - from 25 to 65 for men and to 70 for women in developed countries. Among women it has risen by three months every year for the last 160 years in some countries.

Switzerland has some of the highest numbers of "old old" - aged 90 or over - according to an analysis of census, population and death statistics for the period from 1860 to 2001.

Professor Fred Paccaud and colleagues from the Faculty of Biology and Medicine of Lausanne found that, apart from a dip in 1918, the year of the flu pandemic that killed millions around the world, life expectancy rose by 98 per cent for men and 96 per cent for women.

But the emergence of the extremely old population has only happened in the last 50 years and is chiefly due to improvements in the health of the elderly that started in the 1950s.

Although all countries have seen an increase in longevity, Switzerland has experienced one of the strongest rates, along with Japan, and it has been particularly visible because of the lack of major disasters during the last 150 years, the researchers say.

"The pattern of increase suggests that a combination of factors played a part, related to sanitation, income, nutrition and health care," they write in the Journal of Epidemiology and Community Health.

The 1950s were a crucial period for the development of the oldest old in other countries, such as France, which still holds the record for the world's oldest person, Jeanne Calment, who died in 1997 aged 122.

Possible reasons include improvements in sanitation and socio-economic conditions and medical advances directly benefiting the old, such as antibiotic treatment for pneumonia.

A study in Sweden found death rates among people aged 90 to 94 over the period 1861 to 1999 were directly related to their wealth as measured by manufacturing wages.

The improvement in the economic situation in Switzerland has been massive since World War II, with direct benefits for old people, the researchers say.

Almost two-thirds of the increase in the number of centenarians is attributable to improvements in mortality in the over-80s, they say. One-third is attributable to improvements before 80 and less than 10 per cent to increases in the size of the population.

In England and Wales there were 6000 centenarians in 2001. But the researchers note that in many countries the increases in longevity seen over the last half century are slowing down. Growth of smoking is suggested as one cause.

- INDEPENDENT