Category:Burden of occupational diseases
Work related diseases cause great losses to employees, companies and society at large. Work related attributable fraction (AF) of many diseases may be considerable although the disease is not accepted as an occupational diseases. Disease adjusted life years (DALYs) are often used as metrics for comparison of burden of occupational and work related diseases (BOD). As much as 3.2% of workforce (6.9 million workers) in the EU-27 reported having suffered an occupational accident in last 12 months. About 40% of low back pain has been estimated to be work related: Generally men suffer more from work related diseases and accidents. About 5% of all cancer cases have been estimated to be work related. Different methods have been developed for the evaluation of economic costs to companies and society. Common principle in linking insurance costs to occupational accident rate serves as a good impetus to improve occupational safety and health (OSH) in a company.
The burden of disease (BOD) is the impact of a health problem in an area measured by premature mortality and morbidity. It is a statistical measure indicative of premature death and loss of healthy life years through disabling disease and is often measured by disability-adjusted life years (DALYs). In addition to diseases, also work related accidents contribute to BOD, causing premature death and serious injuries decreasing the quality of life. Work related diseases and accidents are responsible for costs to individual employees, employers, companies, insurance companies and to the society at large.
According to the World Health Organization (WHO, 2003), the concept of work related disease (WRD) comprises diseases in the working population, in which "work environment and the performance of work contribute significantly, but as one of a number of factors, to the causation of disease". There is an occupational component in many common national diseases, even though this is not the main reason responsible for the disease. One can draw a distinction between occupational disease and work related disease, namely:
- An occupational disease Occupational disease is a case of disease recognised by the national authorities as being caused by a factor at work. Occupational diseases are illnesses primarily caused by a physical, chemical or biological factor at the workplace, their attributable fraction is more than 50%. Occupational disease can be either temporary or permanent. There are some differences between various EU countries in this respect and this complicates the comparison between the countries at present. For example, noise-induced hearing loss, repetitive strain injuries, asbestosis. #[Link to main category 4 Dangerous substances, subcategory "CMR", ERO-10-06-c.3 "Asbestos"]#
- Work-related diseases (WRD) comprise occupational diseases and also other diseases, whose etiology is partly affected by work-related factors, but their attributable fraction is less than 50%. These kinds of diseases include musculoskeletal diseases #[Link to main category 6 ergonomics, subcategory "MSDs", ERO-10-06-d.1]#, diseases, cardiovascular diseases, many respiratory diseases, mental disorders and many types of cancer.
- Occupational accident #[Link to main category 7 Safety, subcategory "Accidents and incidents", ERO-10-06-b.1]# is defined as an external, sudden, unexpected, unintended, and violent event, during the execution of work or arising out of it, which causes damage to the health or loss of the life of the employee. In the worst case scenario, it represents a fatal occupational accident. Occupational accidents may cause occupational injuries
- Occupational injury is bodily damage resulting from work.
Various EU countries have slightly different ways of registering of occupational illnesses, injuries and fatalities. The registration of these diseases, injuries and incidents is often poor with underreporting being common. In addition, the definitions of occupational disease and even fatal occupational accidents can vary from country to country #[Link to main category 1 OSH in general, subcategory "Statistics", ERO-10-06-f.5"]#.
The European Commission has issued an European recommendation (2003/670/EC) concerning occupational diseases in Europe. This recommendation aims at achieving a more uniform recognition and registration of occupational diseases throughout Europe. The development of an European schedule of occupational diseases has three main aims: 1) to improve knowledge of the subject at the European level (collection and comparability of data); 2) to improve prevention: the Member States are asked to define quantified objectives with a view to reducing the rate of these diseases and 3) to provide assistance to the affected workers in order to enable them more easily to prove the link between their occupational activities and their disease and apply for compensation.
Methods and metrics used
- [Link to main category 2 OSH management and organisations, subcategory "Risk assessment", ERO-10-06-a.8 "OSH Risk assessment methodologies"]#
Attributable fraction (AF) takes into account both the relative risk of becoming ill from an exposure and the proportion of workers exposed to it. The calculation of burden of disease is carried out on the basis of disease and cause of death registers and epidemiologic studies concerning specific exposed groups. Attributable fraction (AF) is defined as the fraction of diseases (morbidity or mortality), which could have been avoided by removing the exposure or some other risk factor. Often the term population attributable fraction (PAF) or population attributable risk is used, when studies/evaluations refer to the whole population. The attributable fraction can be calculated using the following formula presented originally by Levin (1952):
AF = [p x (RR-1)]/[(p x (RR-1) + 1], where
p = proportion of exposed population,
RR = relative risk of exposed population compared with the whole population (to a specific disease/outcome)
When using the above Levin's formula for calculating of attributable fraction one has to be aware that it is sensitive to various confounders. The relative risks obtained from epidemiologic studies are easily affected by various confounders such as smoking frequency, alcohol consumption, physical exercise, obesity and other occurring occupational exposures. These factors depend on the study design, and the health outcomes and exposures under study. They are difficult to eliminate totally, although today they are taken into account in most epidemiologic studies.
Disability-adjusted life years (DALYs)
DALYs have frequently been used as measure for the calculation of burden of disease in the literature. The concept has been mainly developed within the WHO and World Bank. DALYs offer the possibility to take into account both premature mortality and the decreased quality of life due to a disease. The DALY is calculated as the sum of years of life lost due to premature mortality (YLLs) and the years lived with disability due to disease (YLDs), i.e.
DALY = YLL + YLD
YLD is obtained by multiplying incidence (I=number of cases attributable to exposure) with disability weight of the disease (DW, range: 0-1) and the mean duration (L) of the disease, i.e. YLD = I * DW * D
DALYs attributable to a specific (occupational) risk factor or disease can be calculated by multiplying the disease specific DALYs of the country by the country's attributable fraction (AF) for the risk factor of interest.
Commercial enterprises expend finances on prevention work (occupational safety and health, OSH) according to their legal requirements and social responsibilities. The question arises does prevention pay for itself? Traditional (financial, cost, social, ecological) accounting does not record single-economic costs and monetary benefits of prevention work (Kohstall, 2010). It is often difficult to analyse the real costs of occupational accidents. Up till now the studies have been mainly macroeconomic studies. In 2009 and 2010 case studies in companies collecting cost data of specific accidents and diseases have been conducted through BenOSH study– commissioned by the DG Employment (KOOP 2010). It has been shown that an improvement in occupational safety reduces costs incurred by companies #[Link to main category 2 OSH management and organisation, subcategory "Economic aspects", ERO-10-06-a.6]# . Economic effects can be analysed from different perspectives: from the employee's, employer's, perspective as well as from the viewpoint of society as a whole. Several models have been developed for the calculation of costs of occupational accidents and diseases. Cost of illness (COI) analysis is the most common macro approach. A cost-effectiveness analysis is also a common macroeconomic approach used for comparison of different alternatives. A simple financial appraisal is often used on the micro/company level analysis. For example, one can calculate the costs of the present level of sickness absence. A more advanced form is to evaluate costs of different improvements, e.g. reduction of exposure levels to noise in the company. One example is the Finnish TYTA model and its computer programme, which make it possible to analyze and evaluate the economic effects of the working environment (MSAH, 1999). The model produces information about costs caused by absenteeism due to illness, accidents, staff turnover, disability and alterations in working conditions. At the same time it is a tool, which can motivate the management to improve working conditions in a more systematically manner.
Examples on major studies and projects
The World Health Organization (WHO) has been the forerunner in studies concerning the global burden of disease. The Global Burden of Disease (GBD) project has provided the most comprehensive estimates of mortality and morbidity for more than 135 causes of disease and injury (Nelson et al., 2005). WHO has also developed methodology for calculation of burden of disease. WHO has conducted the so-called Comparative Risk Assessment (CRA) project to estimate global burden of disease from seven major risk categories and environmental and occupational risks are one part of this project (WHO, 2002). They have used attributable fraction methodology and disability adjusted life years (DALY) units in their comparisons. In addition, the disability weights (DWs) needed for the calculation of DALYs have been often defined by WHO and later been used in other studies.
In their large study Nurminen & Karjalainen (2001) estimated the proportion of fatalities related to occupational factors in Finland .They used attributable fraction methodology and several epidemiologic studies, which they applied to Finnish working conditions. They took into account gender differences in exposures and work related mortality. They estimated that the attributable fraction of work related mortality in the relevant disease and age groups was about 7% (10% for men and 2% for women) in 1994. For all diseases and ages the fraction was 4%. With respect to the main categories of death, the attributable fraction became 12% for circulatory diseases, 8% for cancers, 4% for respiratory diseases, 4% for mental disorders, 3% for mental disorders, 3% for nervous diseases, and 3% for accidents and violence. The highest attributable fractions were estimated for lung cancer 24%, ischemic heart disease 17%, chronic obstructive pulmonary disease 12%, and 11% for stroke (see Table 1). The study of Nurminen & Karjalainen has been cited frequently and their estimations have been used in many other studies. However, this study has also been criticized. Coggon (2001) remarked that the methodology may lead to overestimation, if certain epidemiologic studies are generalized to other larger and less exposed populations. He also noted that some of the estimated cancers may not be work related at all. In addition, attributable fractions may vary from country to country and they are dependent on study periods.
Driscoll et al. (2005) evaluated the global burden of occupational diseases due to occupational carcinogens. They used workforce data and the Carex database for exposure estimations and relative risks obtained from various epidemiologic studies. They developed estimates of AFs and DALYs and they calculated that there are 152000 deaths annually from occupational cancers (lung cancer 102000, leukemia 7000, mesothelioma 43000) and nearly 1.6 million DALYs mainly originating from lung cancer and mesothelioma.
Hämäläinen, Takala & Saarela (2006) examined the global burden of occupational accidents. Their study covered 175 countries and eight regions. In general, occupational accidents are underreported, especially in many developing and newly industrialized countries. However, these figures are still often used as baseline for occupational safety and health work. In 1998, the average estimated number of fatal occupational accidents was 350000 and there were 264 million non-fatal accidents.
Hämäläinen, Takala & Saarela (2007 and 2009) evaluated the global burden of fatal work related diseases. They used global mortality scenarios for the years 2000 and 2002. For attributable fractions, they used the values calculated for work related diseases in Finland adjusting them to other countries. Hämäläinen et al. estimated that about 2 million work related deaths take place every year and that men suffer two thirds of those deaths. The largest groups of work related diseases are cancers (25%), circulatory diseases (21%) and communicable diseases (28%).
Takala et al. (2009) have estimated global and European trends for occupational accidents and work-related diseases. For example they calculated that dangerous substances cause annually about 74000 deaths in EU-27 countries, which is about 10% of the corresponding worldwide number. The EU-27 number of fatal accidents reported to ILO was 4422 and the number of occupational accidents (causing at least three days absence from work) was 2.6 million in 2003. Altogether 5580 workers died in a fatal accident in 2007. The number of fatal accidents in the EU-15 has decreased from 5275 persons in 1999 to 3580 persons in 2007. (Eurostat, 2010)
Table 1: Estimated attributable fractions due to work in some major diseases
Source: based on Concha-Barrientos et al., 2004; Nurminen & Karjalainen, 2001
Schulte (2005) carried out a survey and has reviewed studies concerning the burden of occupational diseases and injuries and also addressed the economic costs of these accidents in the United States. The estimate of costs of occupational diseases and injuries was between 128-155 billion USD in 2005. He concluded that the magnitude of occupational disease and injury is significant and underestimated.
It has been estimated that about 35% of employees think that their health is negatively affected by work. Musculoskeletal diseases were reported to be the most common problem #[Link to main category 6 Ergonomics, subcategory "Musculosceletal disorders", ERO 10-06-d.1 "Musculoskeletal disorders"]#. On the other hand, work has also a positive effect to life. The International Labour Organization (ILO) has estimated that the total costs of occupational accidents and work-related diseases are about 4% of the gross national product (GNP) (Hämäläinen et al. 2009; ILO 2005). The European Union estimated that the costs of occupational accidents in EU15 in the year 2000 were at least 55 billion euros a year (ILO, 2005). In particular, mental health problems (depression, anxiety) have become more prominent in recent years in Western Europe and they are not often covered by different insurance systems in many countries. #[Link to main category 9 Psychosocial issues, subcategory "Mental health", ERO 10-06-e.7 "Mental health at work"]#.
As much as 3.0% of workforce (6.9 million workers) in the EU-27 reported having suffered an occupational accident #[Link to main category 7 Safety, subcategory "Accidents and incidents", ERO-10-06-b.1]# in last 12 months in 2007 (Eurostat, 2011). Occupational accidents and diseases cause costs to individuals, employers and society; in fact it is society which bears the greatest part of these emerging costs. Economic costs are not always visible and are often underestimated. Cost calculations often serve awareness raising purposes in companies. Accidents and occupational diseases generally hinder economic growth. It has been shown that countries with low competitiveness indices have a high incidence of fatal occupational accidents and vice versa (ILO, 2005). Sickness absence from work also causes great economic #[Link to main category 2 OSH management and organisation, subcategory "Economic aspects", ERO-10-06-a.6]# losses, and it differs greatly in between various occupations and economic sectors. EU has recently addressed economic incentives to improve occupational safety and published examples on policies and case studies from various EU countries (EU-OSHA; 2010a).
The burden of disease is often different between genders #[link to main category 12 Vulnerable groups, subcategory "Gender"]#. This has traditionally originated from the different jobs done by men and women. Men tend to work in high risk occupations such as those in industry, mining and construction. Women work more often in offices, health and social care sector and service sector. However, the situation is changing and the occupational segregation is decreasing in Europe and worldwide. Many epidemiologic studies and conclusions drawn from them actually reflect the exposure conditions existing decades ago.
Men suffer generally more from:
- occupational cancer
- noise induced hearing loss
- occupational accidents
- heavy lifting
Women suffer generally more from:
- occupational skin diseases
- work related asthma
- harassment at work
Attributable fraction (AF) of work related deaths is considerably higher among men than women#[Link to main category 12 Groups at risk, subcategory "Gender"]#, and this difference is reflected clearly also in in DALYs. Men suffer from cancer and accidents, which tend to decrease disease-adjusted life years considerably. In particular, occupational cancer is responsible for many premature deaths. For example, lung cancer on the average decreases the life span by over 10 years and only about 10% of patients are still alive five years after diagnosis.
Use of burden of disease studies
Long-time limiting illnesses or limiting health conditions are very common among employees at workplaces For example, they include people recovering from cancer, people with allergies, people with musculoskeletal disorders, people suffering from mental disorders etc. Normally their work life ability is evaluated by medical personnel, but they need special attention in any workplace risk assessment. These diseases cause economic costs for employers and employees and their burden of disease can be expressed also in DALY units. Depression is becoming a leading contributor to the burden of disease worldwide and it is often at least partly related to work. People often feel today's work meaningless and without any real purpose. Depression seems to affect women more often than men. The conclusion of an earlier WHO study was that the highest occupational attributable fractions were attributable to low back pain, hearing loss, chronic obstructive pulmonary disease (COPD), asthma, unintentional injuries and lung cancer (Fingerhut et al., 2005).
Risk prevention and management activities in companies and in society should be directed more towards long term limiting illnesses and diseases, which would reduce considerably disability adjusted life years. #[Link to main category 10 Health, subcategory "Health screening and surveillance"]#, #[Link to main category 2 OSH management and organisation, subcategory "Risk assessment", ERO-10-06-a.10 "The role of legislation in OSH Management"]#. For example the prevention of lung cancer and other cancers is important. Approximately one third of cancers are considered preventable (WHO, 2009). As many as 90% of cancers are likely to have an external etiological factor, which means that the prevention possibilities may be even higher. This 90% takes into account the environment in its widest sense, including such factors as diet, lack of physical exercise, obesity, smoking, alcohol use etc. It has been estimated that 70% of mesotheliomas (asbestos), 20% of sinonasal cancer (wood dust, formaldehyde, etc.), 12% of lung cancers (various dusts and chemicals) and 5% of laryngeal cancers (asbestos etc.) could be avoided, if the causative occupational exposure were eliminated. #[Link to main category 4 Dangerous substances, subcategory "CMR", ERO-10-06-c.3 "Asbestos"]#
Strategies for controlling occupational exposures to carcinogens have been set out in the EU Carcinogen Directive (2004/37/EC ) as well as in national legislation (e.g. UK, Finland). It has been argued that priority should be given to controlling those agents that contribute most to the burden of cancer and other serious diseases. High individual risk has also been addressed, particularly in the context where a group of workers is exposed to high concentrations of hazardous substances. Many diseases of public health importance develop slowly and therefore the risks are not taken seriously sufficiently early. A precautionary approach is needed to reduce exposure and risks to occupational carcinogens #[Link to main category 4 Dangerous substances, subcategory "Carcinogenic, mutagenic, reprotoxic (CMR) substances, ERO-10-06-c.6"]#especially, where the risk is not clearly recognizable by employers or employees.
Economic costs from accidents fall mainly on the society and individual workers in most countries. Long term limiting illnesses are responsible for a major economic burden to individuals, companies and society. The calculation of economic costs of accidents and occupational diseases can serve well in awareness raising in companies and as such this may increase their motivation to improve safety and working conditions. In addition, the principle of linking the accident rate in a particular company to its insurance costs could also focus the attention and motivate companies #[Link to main category 2 OSH management and organisation, subcategory "Economic aspects", ERO-10-06-a.6]# to make improvements in occupational safety and health.
Psychosocial issues #[Link to main category 9 Psychosocial issues]# such as work-related stress, violence and harassment have become more important from the point of workers partly due to change of working life in Europe. They have also been considered as important ‘new and emerging’ risks although they are not new as such. This issue emphasizes the importance of good management in companies.
A better understanding of the way in which enterprises tackle all aspects of health and safety is particularly important according to the European Survey of Enterprises on New and Emerging Risks (ESENER) study (EU-OSHA, 2010b).
Coggon, D., ‘Mortality attributable to work’ Scand J Work Environ Health, No 27:3, 2001, pp. 214-15.
Concha-Barrientos, M., Imel Nelson, D., Driscoll T, Punnett, L., Steenland, K., Fingerhut M, et al., ‘The global burden of selected occupational disease and injury risks' In: Ezzati et al. (ed.). Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors, Geneva, WHO, 2004.
Driscoll, T., Nelson, D.I., Steenland, K., Leigh, J., Concha-Barrientos, M., Fingerhut, M., Prüss-Ustün, A., ‘The global burden of disease due to occupational carcinogens’, Am J Ind Med, Vol 48:6, 2005; pp. 419-31.
Directive 2004/37/EC of the European Parliament and the Council of 29 April 2004 on the protection of workers from the risks related to exposure to carcinogens or mutagens at work (Sixth individual Directive within the meaning of Article 16(1) of Council Directive 89/391/EEC). Available at: http://europa.eu/legislation_summaries/employment_and_social_policy/health_hygiene_safety_at_work/c11137_en.htm
EU-OSHA – European Agency for Safety and Health at Work, Economic incentives to improve occupational safety and health: a review from the European perspective, Bilbao, 2010a. Available at: http://osha.europa.eu/en/publications/reports/economic_incentives_TE3109255ENC/view
EU-OSHA – European Agency for Safety and Health at Work, European Survey of Enterprises on New and Emerging Risks (ESENER) – Managing safety and health at work, Bilbao, 2010b. Available at: http://osha.europa.eu/en/publications/reports/esener1_osh_management/view
Fingerhut, M., Driscoll, T., Imel Nelson, D., Concha-Barrientos, M., Punnett, L., Pruss-Ustin, A., Steenland, K., Leigh, J., Corvalan C. , ‘Contribution of occupational risk factors to the global burden of disease – summary of findings.’ Scand J Work Environ Health, Supplement; No. 1, 2005, pp. 58-61.
Hämäläinen, P., Saarela, K.L., & Takala, J., ‘Global trend according to estimated number of occupational accidents and fatal work-related diseases at region and country level.’ Journal of Safety Research, Vol. 40, 2009, pp. 125–39.
Hämäläinen, P., Takala, J. & Saarela, K.L., ‘Global estimates of fatal work-related diseases.’ Am J Ind Med, Vol- 50:1, 2007, pp.28-41.
Hämäläinen, P., Takala, J. & Saarela, K.L., ‘Global estimates of occupational accidents’, Safety Science, Vol 44, 2006, pp. 137-55.
Kohstall, D., 'Final Report – Quality in Prevention – Effectiveness and Efficiency of the Prevention Services of the Social Accident Insurance in Germany', Dresden, 2009. Available at: http://www.dguv.de/iag/de/forschung/forschungsprojekte_archiv/qdp/qdp_abschluss/_dokumente/qdp_komplett_en.pdf
ILO – International Labour Organisation, Safe Work and World Economic Forum, Introductory Report, 2005. Available at: http://www.ilo.org/public/libdoc/ilo/2005/105B09_281_engl.pdf
KOOP – Cooperation Centre (Kooperationsstelle) Hamburg IFE GmbH, institute for international research, development, evaluation and consultation, 'BenOSH, Socio-economic costs of work-related accidents and ill health in comparison to preventive measures,. Kooperationsstelle Hamburg, 2010. Available at: http://www.kooperationsstelle-hh.de/?page_id=52&lang=en
Levin, M.L., ‘The occurrence of lung cancer in man.’ Acta Unio Internationalis Contra Cancrum, No 9, 1953, pp. 531-41.
Nelson, D. I., Concha-Barrientos, M., Driscoll, T., Steenland, K., Fingerhut, M,, Punnett, L., Prüss-Ustün, A., Leigh, J., Corvalan, C., The global burden of selected occupational diseases and injury risks: Methodology and summary, Am J Ind Med., 48(6), 2005, pp. 400-18. Available at: http://www.ncbi.nlm.nih.gov/pubmed/16299700
Nurminen, M., Karjalainen, A., ‘Epidemiologic estimates on the proportion of fatalities related to occupational factors in Finland’, Scand J Work Environ Health, Vol. 27:3, 2001, pp. 161-213.
Schulte, P.A., 'Characterizing the burden of occupational injury and disease', J Occup Environ Med., 47(6), 2005, pp. 607-22
MSAH – Ministry of Social Affairs and Health, ‘The TYTA model - Implement for Evaluating the Company’s Working Environment Costs.’ Ministry of Social Affairs and Health, Department for Occupational Safety and Health, Tampere, Finland, 1999. Available at: http://www.ilo.org/public/english/protection/safework/whpwb/econo/tyta.pdf
Takala, J., Urrutia, M., Hämäläinen, P. & Saarela, K.L., ‘The global and European work environment – numbers, trends, and strategies.’ Scand J Work Environ Health, Vol. 7, 2009, pp. 15-23.
WHO – World Health Organization, Global Action Against Cancer, WHO, Geneva, 2003. Available at: http://www.who.int/cancer/media/en/788.pdf
Links to further reading Commission Recommendation 2003/670/EC of 19 September 2003 concerning the European schedule of occupational diseases. Available at: http://europa.eu/legislation_summaries/employment_and_social_policy/health_hygiene_safety_at_work/c11112_en.htm
EU-OSHA – European Agency for Safety and Health at Work (no publishing date available), Latest news on the global and European burden of disease and injury at work. Retrieved on 15 June 2011, from: http://osha.europa.eu/en/blog/latest-news-on-the-global-and-european-burden-of-disease-and-injury-at-work
WHO – World Health Organization, Comparative risk assessment project (CRA). In: Methodology for assessment of environmental burden of disease (Annex 4.1), WHO, Geneva, 2000. Available at: http://www.who.int/quantifying_ehimpacts/methods/en/wsh0007an4.pdf
WHO – World Health Organization, Task force 15: Global burden of disease (publishing date not available). Available at: http://www.who.int/occupational_health/topics/en/oehtf15.pdf
WHO – World Health Organization, Occupational carcinogens: Assessing the environmental burden of disease at national and local levels, WHO, 2004. Available at: http://www.who.int/quantifying_ehimpacts/publications/9241591471/en/
Worley, H., Depression a Leading Contributor to Global Burden of Disease (2011). In: Population Reference Bureau -website: Retrieved on 10 June 2011, from: http://www.prb.org/Articles/2006/DepressionaLeadingContributortoGlobalBurdenofDisease.aspx
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