West's diseases spread as the world goes grey

The greying of the world is revealed in a report today, which shows that global life expectancy has risen faster in the last half century than in the previous 2,000 years.

Growing prosperity and improving living conditions are contributing to an extraordinary extension of longevity. Life expectancy at birth across the world has risen from 48 in 1955 to 65 today, according to the World Health Organisation. Over the next two decades, the global population of over-65s is set to rise by 82 per cent.

However, as the Western way of life is exported round the world, the Western way of death is following closely in its wake.

In its 1997 report on the state of the world's health, the WHO warns that the ageing population is experiencing a rapid rise in cancer, heart disease and other chronic conditions, which threatens to reduce the benefit of those extra years of life.

The number of over-65s is expected to grow from 380 million today to 690 million by 2020. Over the same period, cancers will rise from 10 million to 15 million cases annually, cases of diabetes will more than double and dementia will become a leading cause of disability.

Launching the report at a press conference in London, Dr Paul Kleihues, director of the International Agency for Research on Cancer in Lyons, France, said the increase in chronic diseases in old age was a testament to the success of efforts to combat infectious diseases, which predominantly kill the young. "The increase in life expectancy is one of our greatest achievements, but longevity without health is an empty prize. Health expectancy is more important than life expectancy. The aim should be to die young as late as possible."

With increasing age, chronic conditions have more time to develop to a deadly or disabling stage, and the globalisation of unhealthy lifestyles, linked to diet, lack of exercise, and smoking, bring on Western patterns of disease. Dr Kleihues said: "We know that the cancers in an area reflect the local lifestyle and with a change of lifestyle there is a change in the disease pattern. We are, nevertheless, surprised at the speed of change."

Large parts of the newly industrialised world now face a double burden - with the chronic conditions linked to growing affluence rising faster than the older ones, linked to poverty and infection, fall.

So-called "diseases of affluence" kill more people in the developing world but cause a higher proportion of deaths in the developed world. Heart disease, the chief affliction of the West, now accounts for more than a quarter of deaths in the developing world. In Central America and the Middle East, heart disease, diabetes and renal disease dominate the medical wards.

Lung cancer rates in European women, who took up smoking later than men, are set to rise by a third by 2005. Dr Kleihues said the priority should be to prevent young people taking up the habit. "All attempts to legislate to restrict smoking by young people in Europe have been blocked by three countries - Germany, the Netherlands and the UK. We hope very much with a new UK government this will change."

Dr Hilary King, WHO medical officer in the division of non-communicable diseases, said the rapid increase of chronic diseases in developing countries could be due to genetic factors: "Non-Caucasians may have a greater underlying susceptibility to these diseases. Individuals who live in harsher parts of the world, where food supplies are erratic, develop the capacity to store energy so that they can survive. But when a Western diet is available that same capacity can become a disadvantage, precipitating diabetes and heart disease."

t A study in the Lancet says more people died world-wide from suicide than from HIV infection in 1990, and more than half the female suicides in the world occurred in China.