World health report

Conquering suffering, enriching humanity

The health transition

As shown in The world health report 1996 - fighting disease, fostering development, infectious diseases kill about 17 million people a year and afflict hundreds of millions of others, particularly in the developing world.

In the industrialized world, infectious diseases are well under control. It is noninfectious diseases - particularly cancer, circulatory diseases, mental disorders including dementia, chronic respiratory conditions and musculoskeletal diseases - that now pose the greatest threat to health in developed countries. These are essentially the diseases that strike later in life and which, as life expectancy increases, will become more prevalent.

Chronic diseases are responsible for more than 24 million deaths a year, or almost half of the global total. The leading causes are circulatory diseases, including heart disease and stroke, cancer and chronic obstructive pulmonary disease.

As life expectancy in developing countries also increases, so does the certainty that people will become more and more prone to diseases that are more common among older age groups. Already, the outlook for most individuals in the developing world is that if they do manage to survive the killer infections of infancy, childhood and maturity, they will become exposed in later life to noncommunicable diseases.

This situation is known as the "epidemiological transition" - the changing pattern of health in which poor countries inherit the problems of the rich, including not merely illness but also the harmful effects of tobacco, alcohol and drug use, and of accidents, suicide and violence. It is also referred to as the "double burden", because of the continuing weight of endemic infectious diseases.