GLOBAL life expectancy could be increased by nearly five years by addressing five factors affecting health - childhood underweight, unsafe sex, alcohol use, lack of safe water, sanitation and hygiene, and high blood pressure, according to a report published by WHO today.

These are responsible for one-quarter of the 60 million deaths estimated to occur annually.

Global Health Risks describes 24 factors affecting health. These are mixture of environmental, behavioural and physiological factors, such as air pollution, tobacco use and poor nutrition.

The report also draws attention to the combined effect of multiple risk factors. Many deaths and diseases are caused by more than one risk factor and may be prevented by reducing any of the risk factors responsible for them.

"More than a third of the global child deaths can be attributed to a few nutritional risk factors such as childhood underweight, inadequate breastfeeding and zinc deficiency," says Colin Mathers, Coordinator for Mortality and Burden of Disease at WHO.

Eight risk factors alone account for over 75% of cases of coronary heart disease, the leading cause of death worldwide. These are alcohol consumption, high blood glucose, tobacco use, high blood pressure, high body mass index, high cholesterol, low fruit and vegetable intake and physical inactivity. Most of these deaths occur in developing countries.

"Understanding the relative importance of health risk factors helps governments to figure out which health policies they want to pursue," says Mathers. "In many countries there is a complex mix of risk factors. Countries can combine this type of evidence along with information about policies and their costs to decide how to set their health agenda." WHO, 27/10/09.