Disease burden


Disease burden is the impact of a
The World Health Organization (WHO) has provided a set of detailed guidelines for measuring disease burden at the local or national level.[4] In 2004, the health issue leading to the highest YLD for both men and women was unipolar depression;[10] in 2010, it was lower back pain.[11] According to an article in The Lancet published in November 2014, disorders in those aged 60 years and older represent "23% of the total global burden of disease" and leading contributors to disease burden in this group in 2014 were "cardiovascular diseases (30.3%), malignant neoplasms (15.1%), chronic respiratory diseases (9.5%), musculoskeletal diseases (7.5%), and neurological and mental disorders (6.6%)."[9]: 549
Statistics
The first study on the global burden of disease, conducted in 1990, quantified the health effects of more than 100 diseases and injuries for eight regions of the world, giving estimates of morbidity and mortality by age, sex, and region. It also introduced the DALY as a new metric to quantify the burden of diseases, injuries, and risk factors.[4][12][13] From 2000 to 2002, the 1990 study was updated to include a more extensive analysis using a framework known as comparative risk factor assessment.[12]
In 2004, the World Health Organization calculated that 1.5 billion disability-adjusted life years were lost to disease and injury.[14][15]
Disease category | Percent of all YPLLs, worldwide[15] | Percent of all DALYs, worldwide[14] | Percent of all YPLLs, Europe[15] | Percent of all DALYs, Europe[14] | Percent of all YPLLs, US and Canada[15] | Percent of all DALYs, US and Canada[14] |
---|---|---|---|---|---|---|
Infectious and parasitic diseases, especially AIDS, tuberculosis, and malaria
|
37% | 26% | 9% | 6% | 5% | 3% |
Neuropsychiatric conditions , such as depression
|
2% | 13% | 3% | 19% | 5% | 28% |
motor vehicle accidents
|
14% | 12% | 18% | 13% | 18% | 10% |
heart attacks and stroke
|
14% | 10% | 35% | 23% | 26% | 14% |
Premature birth and other perinatal deaths (infant mortality )
|
11% | 8% | 4% | 2% | 3% | 2% |
Cancer | 8% | 5% | 19% | 11% | 25% | 13% |
Modifiable risk factors
In 2006, the WHO released a report which addressed the amount of global disease that could be prevented by reducing environmental risk factors.
To measure the environmental health impact, environment was defined as "all the physical, chemical and biological factors external to a person, and all the related behaviours".[16] The definition of modifiable environment included:
- Air, soil, and water pollution with chemicals or biological agents
- Ultraviolet and ionizing radiation
- Noise and electromagnetic fields
- Built environment
- Agricultural methods and irrigation schemes
- Human-made climate change and ecosystem degradation
- Occupational risks, including exposure to long working hours[17]
- Individual behaviors, such as hand-washing and
Certain environmental factors were excluded from this definition:
- Indoor smoke from solid fuel use
- Lead
- Mercury[19]
- Natural human-caused climate change)
- Occupational airborne particulates or carcinogens
- Outdoor air pollution
- Sanitation and hygiene problems
- Second-hand smoke
- Solar ultraviolet radiation
Methodology
The WHO developed a methodology to quantify the health of a population using summary measures, which combine information on mortality and non-fatal health outcomes. The measures quantify either health gaps or health expectancies; the most commonly used health summary measure is the DALY.[3][13][18]
The exposure-based approach, which measures exposure via
A dose-response relationship is a function of the exposure parameter assessed for the study population.
In 2002, the WHO estimated the global environmental burden of disease by using risk assessment data to develop environmentally attributable fractions (EAFs) of mortality and morbidity for 85 categories of disease.[3][4][21] In 2007, they released the first country-by-country analysis of the impact environmental factors had on health for its then 192 member states. These country estimates were the first step to assist governments in carrying out preventive action. The country estimates were divided into three parts:
- Environmental burden of disease for selected risk factors
- This presents the yearly burden, expressed in deaths and DALYs, attributable to: indoor air pollution from solid fuel use; outdoor air pollution; and unsafe water, sanitation, and hygiene. Results are calculated using the exposure-based approach.
- Total environmental burden of disease for the relevant country
- The total number of deaths, DALYs per capita, and the percentage of the national burden of disease attributable to the environment represent the disease burden that could be avoided by modifying the environment as a whole.
- Environmental burden by disease category
- Each country summary was broken down by the disease group, where the annual number of DALYs per capita attributable to environmental factors were calculated for each group.[4]
Implementation and interpretation
The public health impacts of air pollution (annual means of PM10 and ozone), noise pollution, and radiation (radon and UV), can be quantified using DALYs. For each disease, a DALY is calculated as:
- DALYs = number of people with the disease × duration of the disease (or loss of life expectancy in the case of mortality) × severity (varying from 0 for perfect health to 1 for death)
Necessary data include prevalence data, exposure-response relationships, and weighting factors that give an indication of the severity of a certain disorder. When information is missing or vague, experts will be consulted in order to decide which alternative data sources to use. An uncertainty analysis is carried out so as to analyze the effects of different assumptions.[20][22][23][24]
Uncertainty
When estimating the environmental burden of disease, a number of potential sources of error may arise in the measure of exposure and exposure-risk relationship, assumptions made in applying the exposure or exposure-risk relationship to the relevant country, health statistics, and, if used, expert opinions.
Generally, it is not possible to estimate a formal confidence interval, but it is possible to estimate a range of possible values the environmental disease burden may take based on different input parameters and assumptions.[3][4][6] When more than one definition has to be made about a certain element in the assessment, multiple analyses can be run, using different sets of definitions. Sensitivity and decision analyses can help determine which sources of uncertainty affect the final results the most.[6]
Examples
The Netherlands
In
Among the investigated factors, long-term PM10 exposure have the greatest impact on public health. As levels of PM10 decrease, related disease burden is also expected to decrease. Noise exposure and its associated disease burden is likely to increase to a level where the disease burden is similar to that of traffic accidents. The rough estimates do not provide a complete picture of the environmental health burden, because data are uncertain, not all environmental-health relationships are known, not all environmental factors have been included, and it was not possible to assess all potential health effects. The effects of a number of these assumptions were evaluated in an uncertainty analysis.[20]
Canada
Exposure to environmental hazards may cause
Burden of disease attributable to lack of water, sanitation, hygiene
The
In 2023,
Acute respiratory infections were the second largest cause of WASH-attributable burden of disease in 2019, followed by malnutrition and soil-transmitted helminthiasis. The latter does not lead to such high death numbers (in comparison) but is fully connected to unsafe WASH; its "population-attributable fraction" is estimated to be 100%.[26]: vi
The connection between lack of WASH and burden of disease is primarily one of poverty and poor access in developing countries: "the WASH-attributable mortality rates were 42, 30, 4.4 and 3.7 deaths per 100 000 population in low-income, lower-middle income, upper-middle income and high-income countries, respectively."[26]: vi The regions most affected are in the WHO Africa and South-East Asia regions. Here, between 66% and 76% of the diarrheal disease burden could be prevented if access to safe WASH services was provided.[26]: vi
Most of the diseases resulting from lack of sanitation have a direct relation to poverty. For example, open defecation – which is the most extreme form of "lack of sanitation" – is a major factor in causing various diseases, most notably diarrhea and intestinal worm infections.[27][28]
An earlier report byCriticism
There is no consensus on the best measures of the public's health. This may be due to the fact that measurements are used to accomplish diverse functions, such as population health assessment, evaluation of the effectiveness of interventions, formulation of health policies, and projection of future resource needs. The choice of measures may also depend on individual and societal values. Measures that only consider premature death will omit the burden of living with a disease or disability, and measures that combine both in a single measure (i.e. DALYs) need to make a judgment to the significance of these measures compared to each other. Other metrics such as economic costs will not capture pain and suffering or other broader aspects of burden.[31]
DALYs are a simplification of a complex reality, and therefore only give a crude indication of environmental health impact. Relying on DALYs may make donors take a narrow approach to health care programs.
See also
- Climate change and infectious diseases
- Vectorborne diseases
- WASH (water, sanitation and hygiene)
- Waterborne diseases
References
- ^ "WHO | Metrics: Disability-Adjusted Life Year (DALY)". WHO. Retrieved 2020-01-02.
- ^ Prüss-Üstün, Annette; Corvalán, Carlos (2006). "Preventing disease through healthy environments: Towards an estimate of the environmental burden of disease" (PDF). Quantifying environmental health impacts. World Health Organization.
- ^ a b c d e f g Kay, David; Prüss, Annette; Corvalán, Carlos (23–24 August 2000). "Methodology for assessment of Environmental burden of disease" (PDF). ISEE session on environmental burden of disease. Buffalo.
- ^ ISBN 978-9241546201. Archived from the originalon June 12, 2005.
- PMID 26063472.
- ^ PMID 19400963.
- PMID 14757707.
- PMID 34011457.
- ^ S2CID 1598103.
- ^ World Health Organization (WHO) (2004). "Disease incidence, prevalence and disability" (PDF). The Global Burden of Disease. Retrieved 2009-01-30.
- PMID 23245607.
- ^ a b "About the Global Burden of Disease (GBD) project". Health statistics and health information systems. World Health Organization. Archived from the original on October 27, 2008.
- ^ a b "Global burden of disease". World Health Organization.
- ^ a b c d "Standard DALYs (3% discounting, age weights): WHO subregions" (XLS). Disease and injury regional estimates for 2004. World Health Organization.
- ^ a b c d "Standard DALYs (3% discounting, age weights): WHO subregions (YLL)" (XLS). Disease and injury regional estimates for 2004. World Health Organization.
- ^ a b "What is the environment in the context of health?" (PDF). Environmental burden of disease series. World Health Organization.
- PMID 34011457.
- ^ a b Department of Public Health and Environment (2010). "Quantification of the disease burden attributable to environmental risk factors" (PDF). Programme on quantifying environmental health impacts. World Health Organization.
- ^ Öberg, M.; Jaakkola, M.S.; Prüss-Üstün, A.; Schweizer, C.; Woodward, A. (2010). "Second-hand smoke: Assessing the environmental burden of disease at national and local levels" (PDF). Environmental Burden of Disease Series. World Health Organization. Retrieved January 2, 2019.
- ^ a b c Knol, A.B.; Staatsen, B.A.M. (8 August 2005). "Trends in the environmental burden of disease in the Netherlands, 1980–2020" (PDF). National Institute of Public Health and the Environment.
- ^ Fewtrell, Lorna; Prüss-Üstün, Annette; Bos, Robert; Gore, Fiona; Bartram, Jamie (2007). "Water, sanitation and hygiene: quantifying the health impact at national and local levels in countries with incomplete water supply and sanitation coverage" (PDF). WHO Environmental Burden of Disease Series. World Health Organization.
- PMID 31398232.
- PMID 31921418.
- S2CID 235713060.
- ^ a b Wigmore, Cameron (2 November 2007). "Study: Environmental burden of disease in Canada".
- ^ a b c d e f WHO (2023) Burden of disease attributable to unsafe drinking-water, sanitation and hygiene, 2019 update. Geneva: World Health Organization; 2023. Licence: CC BY-NC-SA 3.0 IGO.
- ^ "Call to action on sanitation" (PDF). United Nations. Archived from the original on August 2, 2014. Retrieved 15 August 2014.
- PMID 24066070.
- ISBN 978-92-4-151689-1.
- ^ Gleick P (2002). Dirty Water: Estimated Deaths from Water-Related Diseases 2000–2020 (PDF) (Report). Pacific Institute for Studies in Development, Environment, and Security.
- PMID 16416694.
- ISSN 0015-7120.
Sources
- Lucas, Robyn. "Solar ultraviolet radiation: Assessing the environmental burden of disease at national and local levels" (PDF). Environmental burden of disease series. Vol. 17. World Health Organization.
- "Metrics: Disability-Adjusted Life Year (DALY)". Health statistics and health information systems. World Health Organization.
- "Metrics: Population Attributable Fraction (PAF)". Health statistics and health information systems. World Health Organization. Archived from the original on November 14, 2008.
- "National and regional story (Netherlands) – Environmental burden of disease in Europe: the EBoDE project". National and regional story. European Environment Agency (EEA).
- Öberg, Mattias; Jaakkola, Maritta S.; Woodward, Alistair; Peruga, Armando; Prüss-Ustün, Annette (26 November 2010). "Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries" (PDF). World Health Organization.
- Prüss, Annette; Havelaar, Arie (2001). Fewtrell, Lorna; Bartram, Jamie (eds.). "The Global Burden of Disease study and applications in water, sanitation and hygiene" (PDF). Water Quality: Guidelines, Standards and Health. London: IWA Publishing.
- "The WHO guides on assessing the environmental burden of disease" (PDF). World Health Organization.