Long working hours are linked to risky alcohol consumptionBMJ 2015; 350 doi: https://doi.org/10.1136/bmj.g7800 (Published 13 January 2015) Cite this as: BMJ 2015;350:g7800
- Cassandra A Okechukwu, assistant professor
- 1Department of Social and Behavioral Sciences, Harvard School of Public Health, 677 Huntington Avenue, Kresge Building, Boston, MA 02115, USA
In a linked paper, Virtanen and colleagues (doi:10.1136/bmj.g7772) present a meta-analysis combining published studies (34 cross sectional, n=139 112; two longitudinal, n=6873) with unpublished data (27 cross sectional, n=194 581; 18 longitudinal, n=93 729) to explore associations between long working hours and use of alcohol.1 They found that exposure to long working hours was associated with higher odds of alcohol use in cross sectional studies. Also, compared with working 35-40 hours a week, those working 49-54 and ≥55 hours experienced higher incidence of new onset risky alcohol use (>14 drinks/week in women; >21 drinks/week in men).
They found no heterogeneity in the tested associations based on sex, socioeconomic class, or geographic regions. This meta-analysis supports the longstanding suspicion that among workers subjected to long working hours, alcohol can seem like a fast acting and effective way to dull work related aches and pains and smooth the transition between work life and home life.2 3 Indeed, these findings could add impetus to further regulation of working hours as a public health intervention. If so, those participating in the policy debate should bear in mind that although the literature supports a connection between time spent working and use of alcohol, the generally poor measurement of long working hours could lead to an underestimation of the health costs of existing work conditions.
Most researchers use “weekly number of hours worked” to define exposure, despite calls for more nuanced measures.4 Use of the weekly hours measurement could introduce misclassification and underestimation of the association between long working hours and risky alcohol consumption. Across studies of workers in Australia, Europe, Japan, and North America, highly educated men in “white collar” positions are disproportionately classified as exposed when long working hours are defined according to the number of hours worked each week. Studies show, however, that this group of workers is less vulnerable to wage theft—when time devoted to work (for example, during long commutes between jobsites) is defined as non-work time and remains unpaid.5 6
The possible over-representation of more privileged workers by current measurement of long working hours merits further examination. One mechanism linking long working hours to risky alcohol consumption is that the constraints of time might leave some workers with few choices but to rely on alcohol as a rapid mental and physical analgesic to alleviate the stresses and strains associated with working long hours.2 Total weekly hours does not capture features of hours worked (such as daily number of hours, spread of hours, and type of shift) known to affect the intensity of muscle injury associated with working even in non-manual jobs. Experimental studies report a significant increase in physiological ill effects associated with increasing working hours from 8 to 12 a day.7 Risks of injury also differ according to the spread of hours worked and type of shift, even among adults working at or below the weekly limit of 48 hours set by the European Union Working Time Directive.8 Relative to working eight hours a day and a 40 hour working week, working 12 hours a day for four consecutive days increases the risk of injury by 25% for day shift workers and by 55% for night shift workers.8 Less privileged workers have less control over their schedules and are more vulnerable to working successive days and night shifts.9 Measurement that uses weekly working hours underestimates and misclassifies levels of exposure for these groups of workers.
Another issue worth considering is differential stability—or lack of stability—of weekly schedules among workers. Less privileged workers are again more vulnerable to unstable working hours.4 5 6 9 More importantly, workers with problematic patterns of alcohol consumption (those on a continuum from risky to dependent use) move jobs more often than other workers and might be more vulnerable to schedule changes and intermittent unemployment.10 11 This group also has higher absenteeism,11 so their typical weekly hours might not reflect actual hours worked. Finally, attention must be paid to differences between daily and weekly patterns of alcohol consumption; shift workers, for example, are significantly more likely than others to have risky patterns of daily but not weekly alcohol consumption.12
Where should we place long working hours among the many work related and other risk factors linked to risky use of alcohol? The answer remains elusive. It is important to note, however, that working is associated with a lower prevalence of problem alcohol consumption and a higher chance of recovery from alcohol misuse relative to not working. Job loss and unemployment are established causes and consequences of problem alcohol consumption.10 11
The well designed meta-analysis by Virtanen and colleagues1 supports other evidence that long working hours are an important determinant of workers’ health. Their study also provides a behavioral mechanism through which long working hours, which longitudinal studies have linked to increased incidence of type 2 diabetes and other diseases, could adversely affect health outcomes. At first glance, the 0.7-0.8 percentage point increase in new onset risky alcohol use associated with long working hours might seem negligible. This increase, however, represents more than 600 workers in these prospective samples alone. If the association is causal, that translates to more than two million people with new onset risky alcohol use among labor forces in the 14 countries represented in the study. Any exposure associated with avoidable increases in disease or health damaging behavior, or both, warrants careful examination. 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.
Cite this as: BMJ 2015;350:g7800
Competing interests: I have read and understood the BMJ policy on declaration of interests and declare the following interests: none.
Provenance and peer review: Commissioned; not externally peer reviewed.
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