Researchers at UCL suggest that information on working hours could be useful to GPs when calculating a patient’s risk of heart disease, alongside other health measures such as blood pressure, diabetes and smoking habits.
The research, led by Professor Mika Kivimäki, used data from the Whitehall II study, which has followed the health and wellbeing of over 10,000 civil service workers since 1985. For this study, men and women who worked full time and were free of heart disease or angina at the start of the study were selected, a total of 7,095 study participants.
The researchers collected information on heart risk factors, such as age, blood pressure, cholesterol levels, smoking habits and diabetes. They also asked participants how many hours they worked (daytime and work brought home) on an average weekday. During the 11-year follow-up, the researchers collected information about heart health, including those who had suffered from heart attacks, from medical screenings every five years, hospital data and health records.
Over the course of the study 192 participants suffered a heart attack. People who worked 11 hours or more a day were 67% more likely to have a heart attack than those who worked shorter hours. When the normal measures that doctors use to assess someone’s risk of heart disease were adjusted to take account of this finding, the resulting predictions were far more accurate – an improvement of around 5 per cent, which is equivalent to around 6,000 of the 125,000 people who suffer heart attacks in the UK each year.
Professor Kivimäki said:
“We have shown that working long days is associated with a remarkable increase in risk of heart disease. Considering that including a measurement of working hours in a GP interview is so simple and useful, our research presents a strong case that it should become standard practice. This new information should help improve decisions regarding medication for heart disease. It could also be a wake-up call for people who overwork themselves, especially if they already have other risk factors.”
Professor Stephen Holgate, Chair of the MRC’s Population and Systems Medicine Board, said:
“This study might make us think twice about the old adage ‘hard work won’t kill you’. It’s crucial that we invest in long term studies like the Whitehall II study, which has been running for over a quarter of a century, to test our preconceptions about what really is good or bad for our health. Tackling lifestyles that are detrimental to health is a key area for the MRC, and this research reminds us that it’s not just diet and exercise we need to think about.”
The study was also funded by the British Heart Foundation, the BUPA Foundation, National Institutes of Health and the National Heart, Lung and Blood Institute. The research is published today in the journal Annals of Internal Medicine.
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Notes to editors
Kivimäki M, Batty GD, Hamer M, Ferrie JE, Vahtera J, Virtanen M, Marmot MG, Singh-Manoux A, Shipley MJ. Using additional information on working hours to predict coronary heart disease: A cohort study. Ann Intern Med (April 5, 2011).
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