Indicator Code: DALY
Objective: Environmental Health
Policy Category: Environmental Health
Subcategory: Environmental Burden of Disease
Indicator Short Name: Environmental Burden of
Disease
Indicator Full Name: Disability Adjusted Life Years (DALY) Due to the Environmental Burden of Disease
Indicator Description: The Disability Adjusted Life Year or DALY is a health gap measure that extends the concept of potential years of life lost due to premature death (PYLL) to include equivalent years of ‘healthy’ life lost by virtue of being in states of poor health or disability (Murray et al. 2002). The DALY combines in one measure the time lived with disability and the time lost due to premature mortality. One DALY can be thought of as one lost year of ‘healthy’ life and the burden of disease as a measurement of the gap between current health status and an ideal situation where everyone lives into old age free of disease and disability (WHO 2007).
The WHO also captures environmental impact on human health through the DALY. These DALYs adjust the nominal deaths dueto given, environmentally related diseases to take into account the years of life lost due to premature mortality and the loss in quality of life due to disability (morbidity). They are the sum of the number of life years lost due to premature mortality on account of an environmentally influenced disease and the years of life due to disability caused by that disease.
Units: Years of life lost per 1,000 population
Country Coverage: 192
Reference Year: 2002
Target: 0
Target Source: Expert judgment
Short Source: WHO 2007
Source: WHO (World Health Organization). 2007, Country Profiles of Environmental Burden of Disease. This report draws on WHO/UNICEF (2006).
Taiwan: Department of Environmental Monitoring and Information Management, EPA.
Source URL: http://www.who.int/quantifying_ehimpacts/countryprofiles/en/index.html
Methodology: The complete methodology for calculating DALYs is described in the source publication. The DALY indicator used by the 2008 EPI is an aggregate of DALY data that has been collected by the WHO. In order to represent Environmental Health across a broad spectrum of risks, the 2008 EPI does not limit its inquiry to one source of risk. Instead, the DALY indicator is an un-weighted aggregate sum of DALY data from three sources of environmental health risk: diarrhea (due to inadequate sanitation and unclean drinking water), indoor air (combustion of solid fuels for household use), and outdoor air (concentration of particulate matter in urban areas). Twenty three countries had missing diarrhea data; these were mostly wealthy countries for which it made sense to assume relatively low levels of diarrhea. We analyzed the relationship between per-capita income and diarrhea, and imputed missing values according to the following table:
| Per-capita income† | Imputed Diarrhea DALY |
|---|---|
| >$20,0000. | 0.1 |
| $10,000-$20,000 | 0.5 |
| $5,000-$10,000 | 1.0 |
| $1,900-$5,000 | 4.0 |
We did not impute for countries with per-capita income less than $1900. The imputed values reflect the average observed values within the income range, although for the $5,000-10,000 group we excluded Equatorial Guinea when computing the average because it was anomalously high.
†US Dollars, 2000 USD, PPP
Additional Citations: Murray CJL, Salomon JA, Mathers CD, Lopez AD (eds.) (2002). Summary measures of population health: concepts, ethics, measurement and applications. WHO, Geneva. Available at http://www.who.int/pub/smph/en/index.html
Murray CJL, Lopez AD (1996). The Global Burden of Disease. Cambridge: Harvard University Press.
WHO/UNICEF. 2006. Meeting the MDG Drinking Water and Sanitation. The Urban and Rural Challenge of the Decade. Geneva: World Health Organiztion and United Nations Children’s Fund.