Working long hours increases stroke riskk, researchers found

Those who leave on time are at lesser risk of a potentially fatal stroke or heart attack, researchers from London and Sweden have found. They analysed data on more than 500,000 men and women from the US, Europe and Australia and found that the longer people worked, the more likely they were to have a stroke.

Risk level was compared with that of people working a typical 35 to 40-hour week.

Working 41 to 48 hours a week was associated with a 10 per cent risk increase, which rose higher as the hours mounted up. Working 49 to 54 hours pushed up the chances of a stroke by 27 per cent and 55 or more hours raised the risk by a third. The hardest workers also experienced a more modest 13 per cent increased risk of heart disease.

Scientists employed a meta-analysis technique to pull together results from 25 studies allowing trends to be seen that may have been previously hidden.

Lead author Professor Mika Kivimaki, from University College London, said: “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.”

Exactly why working long hours has such an impact on stroke risk remains unclear. The scientists suggest that as well as stress, unhealthy behaviours such as lack of exercise and high alcohol consumption might be involved.

The findings could have implications on the length of the working day, Dr Urban Janlert, from Umea University in Sweden, wrote in The Lancet.

He wrote: “Although some countries have legislation for working hours - e.g. the EU Working Time Directive gives people the right to limit their average working time to 48 hours per week - it is not always implemented. Therefore, that the length of a working day is an important determinant mainly for stroke, but perhaps also for coronary heart disease, is an important finding.”

Dr Mike Knapton, associate medical director at the British Heart Foundation, which part-funded the study, said the study highlighted to doctors that they need to pay particular attention to cardiovascular risk factors when they advise people who work long hours.

He said: “This research shows an association between long working hours and an increased risk of having a stroke and heart disease.

“It is plausible that there could be a causal relationship behind the link as sudden death following long working hours is often caused by stroke, due to long and repeated periods of stress, although that was not demonstrated in this study.”

Earlier this year, The Stroke Association warned that the number of strokes in middle-aged men in Yorkshire had rocketed by more than a fifth in eight years. Hospital admissions for strokes among men aged 40 to 54 increased to 600 in 2014; while for working aged women, the number of strokes increased by 15 per cent to 400 since 2006.

The charity’s regional head of operations, Julia MacLeod, said the figures represented an “alarming increase” and that stroke could no longer be seen as a disease of older people.