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VIEWPOINT
JOHN ELIAS, MPH, CIH, ROH, CRSP, FAIHA, is a consultant based in Manitoba. He served as head of Air Pollution for the Province of Manitoba, was part of a team that established the Manitoba Workplace Safety and Health Division, served as the first head of Occupational Hygiene in Manitoba, and was the founding president of the AIHA Manitoba Local Section. Send feedback to The Synergist.
The Problem with Occupational Disease Statistics
BY JOHN ELIAS
We have all seen a headline like “Workplace Safety and Health Deaths Reach a New Low.” We have all felt some comfort in the news of our “success.” But what does such a headline really mean? To answer this question, we need to understand where the numbers come from. Usually, as in my home province of Manitoba, the data are derived from accepted compensation claims. These data consist of two parts: Acute hazards. As defined in Manitoba, these are work-related injuries and fatalities that occur when a worker is injured or exposed to a significant amount of a hazardous agent. In such cases, the worker dies immediately or soon after the exposure. This category includes deaths from falls, drowning, highway crashes, and carbon monoxide poisoning, among other causes. Unless proven otherwise, these deaths are presumed to arise from employment. Occupational disease. Where an injury consists of an occupational disease that is, in the opinion of the workers’ compensation board, due in part to the worker’s employment and in part to causes other than employment, the board may determine that the injury is the result of an accident arising out of and in the course of employment only where, in its opinion, the employment is the dominant cause. So, in the case of acute injuries and deaths (safety concerns), the workplace is assumed to be the cause, but for occupational diseases (health), the workplace must be proven to be the dominant cause.
In the case of acute injuries and deaths (safety concerns), the workplace is assumed to be the cause, but for occupational diseases (health), the workplace must be proven to be the dominant cause.
OCCUPATIONAL VS. WORK RELATED How accurate are the workers’ compensation numbers? The incidence of acute hazards as presented through compensation data appears to be a reasonable estimate of work-related deaths and injuries. However, the incidence of occupational disease as presented through compensation data appears to be 1 to 2 orders of magnitude less than estimated by other systems.
Other data sources can be used to supplement the compensation data and address the under-reporting of disease. Examples of other data sources are:
  • labor force surveys: occupational injury information from a household survey
  • occupational disease surveillance: relies on a “schedule” of diseases that are presumed occupational if the schedule’s known exposures are present
  • attributable fractions: the proportion of the total number of cases of the disease that are caused by occupational exposure
  • existing surveys and data systems: data from other systems such as vital statistics or cancer registries can provide insight into occupational diseases
The data generated by these sources reflect what are often called “work-related diseases,” which are distinct from the occupational diseases that appear in statistics from workers’ compensation boards. Recall that compensation boards classify injuries as occupational diseases if employment is determined to be the dominant cause. Work-related disease, in contrast, is any disease where work-related aspects increase the risk of disease together with other factors or where work-related factors aggravate an already existing disease.
The difference between occupational disease and work-related disease is apparent in Table 1, which presents the numbers of deaths per year estimated from work-related disease and accepted occupational disease in Manitoba. Work-related deaths were estimated with attributable fractions and the Manitoba workforce. Occupational deaths are deaths accepted by the Workers Compensation Board of Manitoba. The number of deaths caused by work-related disease is 1 to 2 orders of magnitude higher than the number of deaths whose cause was reported as occupational disease.
While Table 1 reflects the local experience in Manitoba, the data are consistent with those from other sources. For example, a 2017 report published by the Workplace Safety and Health Institute indicated that each year 2.78 million workers die from occupational accidents and work-related diseases. The share of these deaths due to work-related diseases was 86 percent (2.4 million).
Table 1. Deaths from Work-Related and Occupational Diseases in Manitoba, 2000–2013
Tap on the table to open a larger version in your browser.
1 Sources: Council of State and Territorial Epidemiologists (PDF); American Journal of Industrial Medicine; Scandinavian Journal of Work, Environment and Health; National Occupational Research Agenda for Respiratory Health 2 Sources: Statistics Canada, CancerCare Manitoba (PDF) 3 Sources: SAFE Work Manitoba (PDF), SAFE Work Manitoba Occupational Disease and Illness Prevention Strategy
In May 2014, the Journal of Occupational and Environmental Hygiene published a paper that included estimates of workplace deaths for industrialized countries. The relevant data and full paper are available from PubMed. The data showed that estimates for fatal injuries from the International Labor Organization were similar to those reported by the country. As with workers’ compensation data, there was a difference of 1 to 2 orders of magnitude between the number of work-related diseases and occupational diseases.
LACK OF AWARENESS Several factors contribute to the apparent lack of awareness of work-related disease. First, diseases are not readily recognizable as being work related. Chronic diseases may not have an obvious source, and most chronic diseases are only recognized after the worker has left the workplace.
Second, regulations and compliance inspections emphasize safety. For example, in Manitoba there are 30 regulations specifically addressing safety (acute hazards) and eight specifically addressing occupational illnesses. There are many more safety inspectors than health inspectors.
As discussed, illness and death statistics are based on regulatory definitions that attribute deaths to occupational disease only if it is the dominant cause and recognized by the workers’ compensation board. The safety and health industry relies on existing statistics that do not recognize work-related disease. Activities and resources are optimized for this vision of workplace safety and health, and relatively few workers in the safety and health field have a background in health.
As long as safety and health programs are based only on compensation data, the health of workers is unlikely to change—or even be measured.
RESOURCES
Alberta Health Services: “The Economic Burden of Occupational Cancers in Alberta” (June 2010).
American Journal of Industrial Medicine: “Dying for Work: The Magnitude of US Mortality from Selected Causes of Death Associated with Occupation” (May 2003).
CancerCare Manitoba: “Cancer in Manitoba: 2015 Annual Statistical Report” (PDF, 2015).
Council of State and Territorial Epidemiologists: “Occupational Health Indicators: A Guide for Tracking Occupational Health Conditions and Their Determinants” (PDF, June 2015).
Journal of Occupational and Environmental Hygiene: “The Economic Burden of Occupational Non-Melanoma Skin Cancer Due to Solar Radiation” (June 2018).
Journal of Occupational and Environmental Hygiene: “Global Estimates of the Burden of Injury and Illness at Work in 2012” (May 2014).
National Academies Press: “A Smarter National Surveillance System for Occupational Safety and Health in the 21st Century” (2018).
NIOSH: “National Occupational Research Agenda for Respiratory Health” (January 2019).
SAFE Work Manitoba: “The Manitoba Workplace Injury Statistics Report, 2000–2013” (PDF).
SAFE Work Manitoba: “Occupational Disease and Illness-Prevention Strategy” (October 2017).
Scandinavian Journal of Work, Environment and Health, Supplement: “The Global and European Work Environment—Numbers, Trends, and Strategies” (January 2009).
Statistics Canada: “Deaths from Chronic Obstructive Pulmonary Disease in Canada, 1950 to 2011” (November 2015).