Long Working Hours and Risk of Cardiovascular Disease

Abstract

Purpose of ReviewTo summarize the evidence on the relationship between long working hours and cardiovascular disease, such as coronary heart disease and stroke.Recent FindingsLarge-scale meta-analyses with published and individual participant observational data on more than 740,000 men and women free of cardiovascular disease report a link between long working hours (≥ 55 h a week) and the onset of cardiovascular events. Our meta-analytic update of summary evidence suggests a 1.12-fold (95% CI 1.03–1.21) increased risk associated with coronary heart disease and a 1.21-fold (95% CI 1.01–1.45) increased risk of stroke, although the evidence is somewhat inconsistent and the possibility of residual confounding and bias cannot be ruled out. Few studies have examined the mechanisms which may be stress-related, behavioral, or biological. The recent pooled analyses suggest that increased cardiac electric instability and hypercoagulability might play a role.SummaryThe evidence that long working hours are a risk factor for cardiovascular disease is accumulating and suggests a small risk. Studies on the effects of long working hours in high-risk populations and those with pre-existing cardiovascular disease, mechanistic research, and intervention studies are needed to advance this research field.

Objective and subjective working hours and their roles on workers’ health among Japanese employees

“…Long working hours, defined as exceeding h/day at work or greater than 40 h of work a week, are considered to cause workers' physical and psychological health problems, including cardiovascular disease 1,2) , high blood pressure 3,4) , sleep disruption 5) , diabates 6,7) , metabolic syndrome 8,9) , fatigue 10) , injury 11) , depression 12,13) , and other health disorders 14,15) . In Japan, the issue of long working hours has been seriously discussed since the late 1980s because some workers died after they overworked for some duration.…”

Current work hours and coronary artery calcification (CAC): The Multi‐Ethnic Study of Atherosclerosis (MESA)

“…This increasing trend represents a public health problem because of the number and variety of related adverse health consequences. Abundant scientific evidence indicates that long work hours may lead to or are associated with physical and psychological health problems including cardiovascular disease (CVD) . Long work hours may also lead to poor lifestyle behaviors such as insufficient leisure‐time physical activity, less healthy dietary intake, and inadequate sleep duration that not only affects quality of life, but are also associated with adverse health conditions .…”

“…From the Whitehall II study, Kivimaki et al demonstrated that data on working hours may improve risk prediction of coronary heart disease (CHD) using the Framingham risk score in low‐risk, working populations. According to a recent meta‐analysis, the evidence that long working hours are a risk factor for CVD suggests a small increased risk associated with CHD (relative risk: 1.12 [95% confidence interval: 1.03‐1.21] …”

“…The mechanism linking long working hours and CVD is hypothesized as possible effects associated with psychological over-activation, feelings of stress, and their influence on cardiovascular health such as elevated blood pressure, a risk factor for coronary artery calcification (CAC). 20,31 Long work hours may also be related to subclinical CVD through unhealthy lifestyle behaviors or other stress-related mechanisms, one of which could involve increased systemic inflammation (IL-17, C-reactive protein) related to sleep deprivation. 32,33 In a case-control study, long working hours and short sleep duration were independently associated with CHD in men.…”

Preventing overwork-related deaths and disorders—needs of continuous and multi-faceted efforts

“…The former mechanism includes psychosocial stress, physical (noise), and the chemical (dust and toxic chemicals) environment. The latter includes lack of sleep and physical activity . These upstream factors are thought to induce behavioral mechanisms (eg, over eating and drinking alcohol), followed by then clinical stage before manifesting CVD (eg, high blood pressure, dyslipidemia, diabetes, inflammation, atrial fibrillation, and hypercoagulability).…”