Long working hours and alcohol use: systematic review and meta-analysis of published studies and unpublished individual participant data

Abstract

Objective To quantify the association between long working hours and alcohol use.Design Systematic review and meta-analysis of published studies and unpublished individual participant data.Data sources A systematic search of PubMed and Embase databases in April 2014 for published studies, supplemented with manual searches. Unpublished individual participant data were obtained from 27 additional studies. Review methodsThe search strategy was designed to retrieve cross sectional and prospective studies of the association between long working hours and alcohol use. Summary estimates were obtained with random effects meta-analysis. Sources of heterogeneity were examined with meta-regression.Results Cross sectional analysis was based on 61 studies representing 333 693 participants from 14 countries. Prospective analysis was based on 20 studies representing 100 602 participants from nine countries. The pooled maximum adjusted odds ratio for the association between long working hours and alcohol use was 1.11 (95% confidence interval 1.05 to 1.18) in the cross sectional analysis of published and unpublished data. Odds ratio of new onset risky alcohol use was 1.12 (1.04 to 1.20) in the analysis of prospective published and unpublished data. In the 18 studies with individual participant data it was possible to assess the European Union Working Time Directive, which recommends an upper limit of 48 hours a week. Odds ratios of new onset risky alcohol use for those working 49-54 hours and ≥55 hours a week were 1.13 (1.02 to 1.26; adjusted difference in incidence 0.8 percentage points) and 1.12 (1.01 to 1.25; adjusted difference in incidence 0.7 percentage points), respectively, compared with working standard 35-40 hours (incidence of new onset risky alcohol use 6.2%). There was no difference in these associations between men and women or by age or socioeconomic groups, geographical regions, sample type (population based v occupational cohort), prevalence of risky alcohol use in the cohort, or sample attrition rate.Conclusions Individuals whose working hours exceed standard recommendations are more likely to increase their alcohol use to levels that pose a health risk.

Long working hours and depressive symptoms: systematic review and meta-analysis of published studies and unpublished individual participant data

“…However, previous studies show that long working hours are associated with high job demands and high control ("active job") rather than high strain jobs (high demands with low control) (92,93), making low job control and job strain unlikely confounders. Similarly, there is no strong longitudinal evidence linking shift work to depression (94), and long working hours has been found to be only modestly associated with risky alcohol use (30). In combination, unmeasured confounders should be associated both with long working hours and depressive symptoms with an odds ratio of 1.54 (95% CI 1.21-1.81) to entirely explain the present findings (95).…”

“…With previous evidence suggesting that working ≥55 hours per week may be harmful for health (29,30) and with the European Union Directive recommending a limit of 48 hours per week (82) in the present analyses of studies with individual-level data, we used the following categories of hours worked per week: <35, 35-40 (reference group), 41-48, 49-54 and ≥55 hours. This categorization was used in all unpublished datasets and via personal communication for a published study by Wang et al (61).…”

“…The second part of the study included unpublished individual-level data from studies included in the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium, which has previously published several meta-analyses on other outcomes (29,30), or were open access at one of two potential sources: the Inter-University Consortium for Political and Social Research (ICPSR; www.icpsr.umich.edu/icpsrweb/ ICPSR) or the UK Data Service (ukdataservice.ac.uk). Each study has existing approval from their relevant local or national ethics committee, and all participants had given informed consent.…”

“…With previous evidence suggesting that working ≥55 hours per week may be harmful for health (29,30) and with the European Union Directive recommending a limit of 48 hours per week (82) (61). In the Helsinki Health Study (HHS) (74), study members had responded to an enquiry about time worked using a pre-defined categorization (<30, 30-40, 41-50 and >50 hours per week) which, for the purposes of the present analyses, we used 30-40 hours per week (reference group) with >50 working hours as the highest group.…”

Working hours and sleep duration in midlife as determinants of health-related quality of life among older businessmen

“…This insufficient recovery is related to a range of physiological changes such as elevated blood pressure and nervous system activity which subsequently may result in physical and psychological health problems. Furthermore, long working hours and sleep deprivation have been linked with an unhealthy lifestyle such as smoking and excessive use of alcohol [21], which are further linked with adverse health outcomes. This might also be why adjustment for smoking and SRH diluted the association between the combined midlife work/sleep variable and the RAND-36 domains in old age.…”