Long working hours linked to higher risk of stroke

20th August 2015 - Putting in extra hours at work may significantly raise your risk of having a stroke, says a study.

International researchers found that people who worked 55 hours or more each week have a 33% higher risk of stroke than those who work a standard 35 to 40 hours each week.

They also found a smaller association between long hours and coronary heart disease.

Heart disease

The researchers analysed data from 25 studies involving a total of 603,838 men and women from Europe, the US and Australia. The individuals had been monitored for an average of 8 and a half years.

It found a 13% higher risk of being diagnosed, hospitalised or dying from coronary heart disease among those putting in at least 55 hour of work a week, compared with those working for 35 to 40 hours. These findings were independent of the individual's age, sex or socioeconomic status.

Risk of stroke

An analysis of 17 studies involving 528,908 men and women, who were followed up for an average of 7.2 years, found a 1.3 times higher risk of stroke in people working 55 hours or more a week compared with those working standard hours.

This association held true even after taking into account other factors such as smoking, alcohol consumption, and physical activity, as well as standard cardiovascular risk factors including high blood pressure and high cholesterol.

The researchers stress that the longer people worked, the higher their chances of a stroke. For example, compared with people who worked standard hours, those working between 41 and 48 hours had a 10% higher risk of stroke, and those working 49 to 54 hours had a 27% increased risk of stroke.

The authors say further research is needed to fully understand the relationship between working hours and stroke risk. However, they suggest that individuals who work long hours might be tempted into unhealthy habits, such as drinking more alcohol and taking less exercise.

Co-author Professor Mika Kivimäki from University College London says in a statement: "Health professionals should be aware that working long hours is associated with a significantly increased risk of stroke, and perhaps also coronary heart disease."

Looking after your health

Dr Shamim Quadir, research communications manager at the Stroke Association, says the findings are an important contribution to our knowledge of what causes strokes. He says in an emailed statement: "It is difficult to establish what may cause this link between working long hours and stroke risk. Nevertheless, the findings of the study underline how important it is to look after your health to help prevent a stroke. This includes taking regular exercise and eating a healthy, balanced diet.

"Working long hours can involve sitting for long periods of time, experiencing stress and leads to less time available to look after yourself. There is also some evidence suggesting that people who work long hours tend to drink more heavily - which is a known risk factor for stroke.

"We advise that you have regular blood pressure checks; if you’re at all concerned about your stroke risk you should make an appointment with your GP or health professional