Worked to Death? A census-based longitudinal study of the relationship between the numbers of hours spent working and mortality risk

Background There has been an increasing interest in the health effects of long<br/>working hours, but little empirical evidence to substantiate early<br/>10 case series suggesting an increased mortality risk. The aim of the<br/>current study is to quantify the mortality risk associated with long<br/>working hours and to see if this varies by employment relations and<br/>conditions of occupation.<br/>Methods A census-based longitudinal study of 414 949 people aged 20-59/64<br/>15 years, working at least 35 h/week, subdivided into four occupational<br/>classes (managerial/professional, intermediate, own account workers,<br/>workers in routine occupations) with linkage to deaths records<br/>over the following 8.7 years. Cox proportional hazards models were<br/>used to examine all-cause and cause-specific mortality risk.<br/>20 Results Overall 9.4% of the cohort worked 55 or more h/week, but this<br/>proportion was greater in the senior management and professional<br/>occupations and in those who were self-employed. Analysis of 4447<br/>male and 1143 female deaths showed that hours worked were<br/>associated with an increased risk of all-cause mortality only for<br/>25 men working for more than 55 or more h/week in routine/semiroutine<br/>occupations [adjusted hazard ratios (adjHR) 1.31: 95%<br/>confidence intervals (CIs) 1.11, 1.55)] compared with their peers<br/>working 35–40 h/week. Their equivalent risk of death from cardiovascular<br/>disease was (adjHR 1.49: 95% CIs 1.10, 2.00).<br/>30 Conclusions These findings substantiate and add to the earlier studies indicating<br/>the deleterious impact of long working hours but also suggest that<br/>the effects are moderated by employment relations or conditions of<br/>occupation. The policy implications of these findings are discussed.