The World Health Organisation (WHO) identified the top 10 risks to human health on a worldwide basis, in its annual report. The risks are rated by the WHO according to the number of deaths they cause and their estimated impact on healthy lives. About 56 million people die every year in the world.

Underweight:
Lack of food for children and mothers caused 3.4 million deaths in the world in 2000. About 170 million children suffer from malnourishment in poor countries and more than three million of them die every year.

Unsafe sex:
Unsafe sex was at the root of 2.9 million deaths in 2000, mainly due to HIV/AIDS which is the fourth cause of death in the world. In Africa, more than 99 percent of HIV infections are due to unsafe sex. Average life expectancy in the most affected areas of sub-Saharan Africa is 47 years, compared to an estimated 62 years without the disease.

High blood pressure:
High blood pressure causes 7.1 million deaths a year, or 13 percent of all deaths. It is also responsible for 62 percent of strokes and 49 percent of heart attacks.

Smoking/tobacco:
Tobacco contributed to 4.9 million deaths in 2000, about 8.8 percent of all deaths worldwide. The WHO believes that 8.4 million people will die every year by 2020 as a result of smoking or tobacco consumption.

Alcohol:
Alcohol is behind 1.8 million deaths a year. It is estimated to cause 20 to 30 percent of some types of cancer and liver disease. Alcohol is also a factor in a large proportion of murders, road accidents and self-inflicted injuries.

Unsafe water and sanitation:
Poor quality water supply and inadequate sanitation cause 1.7 million deaths a year. It is also responsible for most cases of infectious diahorrea.

Cholestorol:
Excessive cholestorol causes 4.4 million deaths, and 18 percent of cardiovascular illnesses.

Indoor smoke:
Solid fuels such as coal or wood are still heavily used for cooking or heating in poor countries, mainly in confined spaces. Indoor smoke causes about 35.7 percent of respiratory infections, 22 percent of chronic lung disease and 1.5 percent of some types of cancer.

Iron deficiency:
Iron deficiency contributes to about 800,000 deaths a year in the world. Two million people are suffering from iron deficiency.

Overweight:
In high or middle income countries, one billion adults are estimated to be overweight, and 300 million are rated as suffering from obesity. More than 500,000 people die each year in north America and Europe because of illnesses related to obesity.