Neurodegenerative diseases and risk factors: a literature review.

Degenerative diseases of the central nervous system are significant causes of mortality among elderly people in industrialized countries. For the most part, the causes of these diseases are unknown. It is also very difficult to diagnose this type of disease quickly and accurately. This article reviews the epidemiological research on the principal neurodegenerative disorders, focusing on geographical, hereditary and viral and toxicological exposure correlates. We look in particular at the effect of exposure to toxins as well as the effect that deficiencies of elements such as calcium and selenium could have on the development of these neurological diseases. We also consider the possible protectionist effect of some variables on the development of certain neurological diseases.