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The World Health Organization (WHO) and International Labour Organization (ILO) have recently released the first Joint Estimates of work-related Burden of Disease and Injury.
How does working long hours result in cardiovascular disease and stroke?
Evidence suggests that working long hours can cause mortality and morbidity from heart disease and stroke through two main “pathways”. The first is through physiological responses to psychosocial stress: working long hours continually activates the autonomic nervous system, immune system and, in turn, associated stress responses, with excessive release of stress hormones (e.g. adrenalin, noradrenalin and cortisol). This triggers reactions in the cardiovascular system (e.g., those that results in low heart rate variability and/or sustained high blood pressure) and lesions that cause a change in tissue (e.g., leading to the formation of fatty deposits in the arteries in coronary vessels).
The second pathway is through health-harming behavioural responses to stress, which include tobacco use, alcohol use, unhealthy diet, physical inactivity and, in turn, impaired sleep and poor recovery, all established risk factors for ischemic heart disease and stroke.
Work-related diseases and injuries were responsible for the deaths of 1.9 million people in 2016, according to the first joint estimates from the World Health Organization (WHO) and International Labour Organization (ILO).
What are the estimates based on?
WHO and ILO conducted two systematic reviews and meta-analyses, supported by a large number of individual experts. Key findings were:
Compared with working 35-40 hours/week, working ≥55 hours/week may have led to a moderate increase of an estimated 17% in the risk of acquiring ischaemic heart disease, when followed up between one year and 20 years. This was based on a pooled analysis of 339,680 participants in 22 cohort studies.
Compared with working 35-40 hours/week, working ≥55 hours/week may have led to a moderate increase by 35% in the risk of acquiring stroke. This was based on a pooled analysis of 162,644 participants in 7 studies.
What were the major occupational risk factors studied?
The study considers 19 occupational risk factors, including exposure to long working hours and workplace exposure to air pollution, asthmagens, carcinogens, ergonomic risk factors, and noise. The key risk was exposure to long working hours – linked to approximately 750,000 deaths.
Which WHO Regions are the worst affected?
Exposure to long working hours
In 2016, the percentage of people working 55 hours or more a week was highest in WHO’s South-East Asia region, at 11.7%, followed closely by Africa and the Eastern Mediterranean (each at 11.4%). It was lowest in Europe at 3.5%.
Over time, from 2000 to 2016, exposure prevalence (the proportions of those working 55 hours or more a week) increased most in the Western Pacific; it decreased the most in Africa.
Burdens of disease from heart disease and stroke attributable to long working hours
Of all regions in 2016, South-East Asia had by far the largest number of deaths caused by ischaemic heart disease attributable to long working hours, at 160,000 deaths. In relative terms, South-East Asia still had the largest death rate at 11.4 deaths per 100,000 people. Over 2000-2016, the number of deaths increased in all regions, except Europe.
In 2016, the largest number of deaths by stroke attributable to working long hours was estimated in South-East Asia (159,000 deaths). In relative terms, South East Asia had the highest death rate at 11.3 deaths/100,000 population. Between 2000 and 2016, out of all regions, South-East Asia and Africa saw the greatest increase in the number of deaths, while Europe had the greatest relative decrease.
Are Men and Women affected to the same extent?
Exposure to long working hours
Men, as well as adults of the early middle-age groups, were overrepresented among those working 55 hours or more a week.
Burdens of disease from ischaemic heart disease and stroke attributable to long working hours
For ischaemic heart disease attributable to long working hours, men carried a larger burden than women, and the numbers and rates of deaths increased with age up to 70 years. Both in absolute and in relative terms, men and older age groups (60–74) carried a larger burdenfrom deaths from stroke attributable to long working hours.
What were the major Non-communicable causes of premature death?
Non-communicable diseases accounted for 81 per cent of the deaths. The greatest causes of deaths were
Occupational injuries caused 19 per cent of deaths (360,000 deaths).
Working 55 hours or more per week increases the risk of stroke by 35% compared to those working 35-40 hours per week.
Working 55 hours or more per week increases the risk of heart disease by 17% compared to those working 35-40 hours per week.
What can be done to protect workers’ health due to long working hours?
Governments, employers and workers can take the following actions to protect workers’ health:
Governments, in consultation with employers and workers, can introduce, implement and enforce laws, regulations and policies that ban mandatory overtime and ensure maximum limits on working time.
Bipartite or collective bargaining agreements between employers’ and workers’ associations can arrange working time to be more flexible, while at the same time ensuring that maximum limits are not crossed.
A heathy and green recovery from the labour consequences of the COVID-19 pandemic could include a sharing of working hours between workers to ensure that numbers of hours worked do not climb above 55 or more per week, to prevent increased risk and burden of cardiovascular disease.
When planning actions/ interventions to prevent work-related health loss, one must follow the Hierarchy of Controls shown below:
The most effective strategy is to eliminate the risk factor from the work environment.