Public health is the science and art of promoting health, preventing disease, and prolonging
life through the organised efforts of society (WHO 1998, p. 3).
This [20th] century has seen greater gains in health for the populations of the world than at any
other time in history. These gains have been made partly as a result of improvements in income
and education, with accompanying improvements in nutrition, hygiene, housing, water supply
and sanitation. They are also the result of new knowledge about the causes, prevention and
treatment of disease and the introduction of policies that have made intervention programmes
more accessible. The greatest advances in health have been made through a combination of
structural change and the actions of individuals (Nutbeam 2000 p.1).