Disability-Adjusted-Life-Year
- Slovak term: Slovenský termín
- Disability-Adjusted-Life-Year (DALY) is a summary measure of population health that combines the impact of illness disability and mortality on population health (WHO 2009).
- See also: burden of disease
Explanation
Traditionally, health liabilities were expressed using one measure : expected or average number of Years of Life Lost (YLL). This measure does not take the impact of disability into account, which can be expressed by : Years Lived with Disability (YLD). DALYs are calculated by taking the sum of these two components in a formula : DALY = YLL + YLD (WHO 2009).
The DALY relies on an acceptance that the most appropriate measure of the effects of chronic illness is time, both time lost due to premature death and time spent disabled by disease. One DALY, therefore, is equal to one year of healthy life lost. Japonese life expectancy statistics are used as the standard for measuring premature death, as the Japanese have the longest expectancies (WHO 2009).
Example
A person in Southern Africa disabled by blindness who then dies aged 45 has lost several years of full health as a result of blindness, but also 35 years of life compared to the average life expectancy of 80 in Japan.
References
- WHO (2009) Health impact assessment glossary: E-learning modules.
