Assessment of the health status of a population as a whole is as important as evaluation of the health of a single person is part of everyday medical practice. The majority of the methods used so far have focused on specific problems or one facet of the multidimensional concept of population health.
Development of methods with higher explanatory power started in the mid-forties and initiated the DALY (Disability Adjusted Life Years) methodology in 1990, when a Global Burden of Disease study was carried out by the World Health Organisation (WHO). This approach is one of the most widespread tools for describing the health status of a population by summing up health losses due to death as well as due to disease.
The mortality component expresses the gap (loss of years lived) between expected age at death and actual age. The disease component describes loss of perfect health due to illness. Every disease causes a decrease in life quality, for example, if a person suffers from a disease, life quality down by half, and in 10 years he or she loses five years of life in perfect health. Total loss of years by age-gender groups and disease provides the necessary overview of population health in the most important aspects.
This overview focuses on the DALY methodology but enlists and describes also selected disease burden studies conducted worldwide as an example of the use of this approach.