Long working hours linked to high stroke risk1 min read . Updated: 20 Aug 2015, 07:16 AM IST
A study shows 13% increased risk of coronary heart disease in people working 55 hours or more per week compared with those working for 35-40 hours
Working 55 hours or more per week is linked to a 33% greater risk of stroke and a 13% higher risk of developing coronary heart disease compared with working 35-40 hours a week, said a study published in The Lancet.
This is the largest study in this field so far, involving 600,000 individuals.
Mika Kivimäki, professor of epidemiology at University College London, examined the effects of longer working hours on cardiovascular disease up to 20 August 2014.
Analysis of data from 25 studies involving 603,838 men and women from Europe, the US and Australia, who were tracked for an average of eight-and-a-half years, found a 13% increased risk of incident coronary heart disease in people working 55 hours or more per week compared with those working for 35-40 hours, even after taking into account risk factors including age, sex and socioeconomic status.
Further, data from 17 studies involving 528,908 men and women who were followed up for an average of seven years and two months, found a 1.3 times higher risk of stroke in individuals. This association remained even after taking into account smoking, alcohol consumption and physical activity, and standard cardiovascular risk factors including high blood pressure and high cholesterol.
Importantly, the researchers found that the longer people worked, the higher their chances of a stroke. For example, compared with people who worked standard hours, those working for 41-48 hours had a 10% higher risk of stroke, and those working 49-54 hours had a 27% increased risk of stroke.
Although the causal mechanisms of these relationships need to be better understood, the authors suggest that increasing health-risk behaviours, such as physical inactivity and high alcohol consumption, as well as repetitive triggering of the stress response, might increase the risk of stroke.
“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," said Kivimäki. “Health professionals should be aware that working long hours is associated with a significantly increased risk of stroke, and perhaps also coronary heart disease."
According to Urban Janlert from Umeå University in Sweden, “Long working hours are not a negligible occurrence. Among member countries of the Organisation for Economic Cooperation and Development (OECD), Turkey has the highest proportion of individuals working for more than 50 hours per week (43%), and the Netherlands the lowest (<1%)."