Employees who work more than 48 hours per week are more likely to engage in risky alcohol consumption than those who work standard weeks, finds a new study published in The BMJ.

Risky alcohol consumption is considered as more than 14 drinks per week for women and more than 21 drinks per week for men. It is believed to increase risk of adverse health problems, including liver diseases, cancer, stroke, coronary heart disease and mental disorders.

In order to protect the health and safety of the workforce, the European Union Working Time Directive (EUWT) ensures that workers in EU countries have the right to work no more than 48 hours a week, including overtime. But many people, for example well educated managers and professionals work much longer hours to achieve faster promotions, salary increases, and more control over work and employment.

Previous research has found a link between working longer hours and risky alcohol consumption, but this has involved only small, tentative studies. While alcohol may help to ease the stress of working long periods of time, risky consumption is also associated with difficulties in the workplace, including increased sick leave, poor performance, impaired decision making and occupational injuries.

Marianna Virtanen and colleagues here provide the first systematic analysis on the association between long working hoursand alcohol use.

In a cross sectional analysis of 333,693 people in 14 countries, they found that longer working hours increased the likelihood of higher alcohol use by 11%. A prospective analysis found a similar increase in risk of 12% for onset of risky alcohol use in 100,602 people from 9 countries.

Individual participant data from 18 prospective studies showed that those who worked 49-54 hours and 55 hours per week or more were found to have an increased risk of 13% and 12% respectively of risky alcohol consumption compared with those who worked 35-40 hours per week.

The authors point out that no differences were seen between men and women or by age, socioeconomic status or region.

Although, in absolute terms, the difference between the groups was relatively small, the authors argue that any exposure with avoidable increases in disease or health damaging behaviour, or both, warrants careful examination.

The findings also provide support for the recommended 48 hours per week as enforced by the EUWT.

"The workplace is an important setting for the prevention of alcohol misuse, because more than half of the adult population are employed," write the team of researchers. "Further research is needed to assess whether preventive interventions against risky alcohol use could benefit from information on working hours."

In an accompanying editorial, Cassandra A Okechukwu, an Assistant Professor at Harvard School of Public Health, US, writes that the results have implications for exceptions to recommended weekly working hours, which could lead to more alcohol consumption and greater health risks for millions of people. She suggests that the regulation of working hours could constitute a public health intervention and concludes: "Given mounting pressure to exclude an increasing proportion of workers from current standards that limit working hours in Europe and other developed countries, long working hours is an exposure that we cannot afford to ignore."