A large meta-analysis by researchers working in the United Kingdom found what we already knew: stress might be bad for your health.
The study, published in The Lancet was a meta-analysis that examined the effects of working long hours on both risk of coronary heart disease and risk for stroke. The results showed that working long hours is linked to an increased risk for both.
To assess risk for coronary heart disease the researchers, working at University College in London, analyzed data from 25 studies involving over 600,000, people and which followed them for an average of 8.5 years. They found that working more than 55 hours a week was associated with a 13 percent increased risk for coronary heart disease (which included a new diagnosis, hospitalization or death) compared to people who worked 35 to 40 hours a week. This relationship persisted even after accounting for other coronary heart disease risk factors such as age, sex, and socioeconomic status.
For assessing stroke risk, the researchers analyzed data from 17 studies with over 525,000 people and followed them for an average of 7.2 years. Researchers found that working more than 55 hours per week was linked with a 33 percent higher chance of stroke compared to working between 35 and 40 hours per week. Again this association was still there even after the researchers accounted for other risk factors such as smoking, alcohol consumption, physical activity, and standard cardiovascular risk factors.
It was interesting that the stroke association exhibited a dose dependent relationship, lending credence to the idea this might not just be statistical noise. People who worked from 41 and 48 hours had a 10 percent increased risk of stroke and those working 49 to 54 hours had a 27 percent increased risk of stroke over those working 35-40 hours per week.
The average American works 41 hours per week, more than any other industrialized country. According to a Gallop poll from 2014, 39 percent of Americans work more than 50 hours per week and 18 percent work more than 60 hours per week.
The study s leader Mika KivimÃ¤ki, Professor of Epidemiology, had this to say the pooling of all available studies on this topic allowed us to investigate the association between working hours and cardiovascular disease risk with greater precision than has previously been possible. Health professionals should be aware that working long hours is associated with a significantly increased risk of stroke, and perhaps also coronary heart disease.