A newly released study co-authored by a UCLA researcher found long working hours led to 745,000 deaths from stroke and ischemic heart disease in 2016 globally, a 29% increase since 2000.
In what’s billed as the first global analysis of the loss of life and health associated with working long hours, the World Health Organization and the International Labour Organization estimate that, in 2016, 398,000 people died from stroke and 347,000 from heart disease as a result of having worked at least 55 hours a week.
Between 2000 and 2016, the number of deaths from heart disease due to working long hours increased by 42%, and from stroke by 19%.
“Our working group of 21 experts from 10 countries from around the globe found 37 studies on the effect of long working hours on ischemic heart disease,” said Dr. Jian Li, a UCLA Fielding School of Public Health professor and a co-author of the study. “This huge body of evidence was by consensus rated as sufficient evidence for harmfulness & showed an increased risk of ischemic heart disease of 17%.”
The findings were published Monday in the journal Environment International.
The work-related disease burden is particularly significant in men — 72% of deaths occurred among males — people living in the Western Pacific and Southeast Asia regions, and middle-aged or older workers, said Li, who also has an appointment at the UCLA School of Nursing.
Most of the deaths recorded were among people aged 60-79, who had worked for 55 hours or more per week between the ages of 45 and 74.
“Our finding that long working hours increase ischemic heart disease risk is groundbreaking,” said co-author Dr. Tracey J. Woodruff, director of the Program on Reproductive Health & the Environment at UC San Francisco. “Studies like this cannot happen without good science and rigorous systematic review methods. This type of evidence is critical to decision-making and protecting public health.”
With working long hours now known to be responsible for about one-third of the total estimated work-related burden of disease, it is established as the risk factor with the largest occupational disease burden. This shifts thinking toward a relatively new and more psychosocial occupational risk factor to human health, according to the researchers.
The study concludes that working 55 or more hours per week is associated with an estimated 35% higher risk of a stroke and a 17% higher risk of dying from ischemic heart disease, compared to working 35-40 hours a week.