Disability adjusted life years

Slovak term: Slovenský termín

1. A summary measure of population health that combines the impact of illness disability and mortality on population health (WHO 2009).
2. Population metric of life years lost to disease due to both morbidity and mortality (WHO 2006).
3. Acronym: DALY

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. Japanese life expectancy statistics are used as the standard for measuring premature death, as the Japanese have the longest life expectancies (WHO 2009).

The DALY is the sum of years of life lost by premature mortality (YLL) and years of healthy life lost in states of less than full health, i.e., years lived with a disability (YLD), which are standardized by means of severity weights. Thus: DALY = YLL + YLD (WHO 2004).

References

• WHO (2009) Health impact assessment glossary: E-learning modules
• WHO (2006) Guidelines for the safe use of wastewater, excreta and greywater
• WHO (2004) Guidelines for drinking-water quality, 3rd ed.

Links

• WHO — The Health and Environment Lexicon