The final cause of death is usually the failure of the vital centres in the brain that control the beating of the heart and the act of breathing. The important practical question, however, is what disease, injury or other agent has led to this failure. Sometimes the cause may be obvious – for example, pneumonia, coronary thrombosis or brain damage in a road accident. Often, however, the cause can be uncertain, in which case a POST-MORTEM EXAMINATION is necessary.

The two most common causes of death in the UK are diseases of the circulatory system (including strokes and heart disease) and cancer.

Death rates and figures on the causes of deaths are essential statistics in the study of EPIDEMIOLOGY which, along with information on the incidence of illnesses and injuries, provides a map of how health is changing over time in different communities. Such information is valuable in planning preventive health measures (see PUBLIC HEALTH) and in identifying the natural history of diseases – knowledge that often contributes to the development of preventive measures and treatments for those diseases.