Life expectancy around the world has risen dramatically, by 11 years for men and 12 years for women over the last four decades, but we are paying the price in more mental and physical health problems, according to the biggest-ever study of the global burden of disease.

A massive international research project, which took five years and involved 500 people, has produced the most comprehensive and ambitious database of the world’s health ever attempted. It shows dramatic changes since 1970, with the rapid decline in deaths from infectious diseases and malnutrition and the vastly improved survival of small children.

Most deaths in the world are now from heart disease and stroke, which killed an estimated 12.9 million people in 2010, a quarter of the global total.

High blood pressure is the biggest risk factor for death today — responsible for 9.4 million deaths and seven per cent of disability — followed by smoking, which caused 6.3 million deaths. Alcohol comes third, responsible for five million deaths worldwide. Physical inactivity and diet — particularly those with high levels of sodium or salt and low levels of fruit consumption — were responsible for 12.5 million deaths.

With lengthening lives, however, the biggest issue for humanity may well be disability. Although we live longer, we do not necessarily enjoy more years of health. In the two decades to 2010, men's life expectancy increased by 4.7 years and women's by 5.1 years — but the extra years of good health were only 3.9 years and four years respectively, which suggests that illness and disability are taking a greater toll of our lives.

Women in four countries however — Japan, Singapore, South Korea and Spain — have a healthy life expectancy greater than 70 years. In no country do men enjoy the same length of healthy life and only in Afghanistan, Jordan and Mali do they live longer in good health than women.

Japanese women also have the longest life expectancy, living on average almost to 86, while the longest lived men are in Iceland, with life expectancy of 80 years.

The findings that people are living longer but with worse health could trigger a rethink not only in our expectations but also the way all health systems work.

By arrangement with the Guardian