Shift work and cardiovascular disease—pathways from circadian stress to morbidity

Centre of Expertise on Human Factors at Work, Finnish Institute of Occupational Health, FI-00250 Helsinki, Finland.
Scandinavian Journal of Work, Environment & Health (Impact Factor: 3.1). 03/2010; 36(2):96-108. DOI: 10.2307/40967836
Source: PubMed

ABSTRACT In order to establish a causal relation between shift work and cardiovascular disease (CVD), we need to verify the pathways from the former to the latter. This paper aims to review the current knowledge of the mechanisms between shift work and CVD. Shift work can increase the risk of CVD by several interrelated psychosocial, behavioral, and physiological mechanisms. The psychosocial mechanisms relate to difficulties in controlling working hours, decreased work-life balance, and poor recovery following work. The most probable behavioral changes are weight gain and smoking. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changed lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The data provide evidence for possible disease mechanisms between shift work and CVD, but compelling evidence on any specific mechanism is missing.

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Available from: Sampsa Puttonen, Jul 28, 2015
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    • "Several hypotheses have been proposed to explain the link between shiftwork and CVD (Puttonen et al., 2010). Sleep disturbance has been suggested as an important factor, although evidence for this remains somewhat limited. "
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    ABSTRACT: Many of the health problems that are more prevalent among shiftworkers are thought to be linked to their heightened susceptibility to metabolic syndrome, i.e., the association of even moderate degrees of visceral obesity, dyslipidemia, abnormal blood pressure, and serum glucose levels in the same individual. Although previous studies have identified associations between shiftwork and metabolic syndrome, there is relatively little evidence to date of how the risk of developing it varies as a function of exposure to shiftwork. The current study seeks to confirm earlier findings of an association between shiftwork exposure and metabolic dysfunction, and to examine the impact of exposure duration, while adjusting for a number of covariates in the analyses. The analyses were based on data from VISAT, a study involving the measurement of physiological, behavioral, and subjective outcomes from 1757 participants, 989 being current or former shiftworkers. The sample comprised employed and retired wage earners, male and female, who were 32, 42, 52, and 62 yrs old. The first analysis sought to confirm previous findings of an association between exposure to shiftwork and the risk of developing metabolic syndrome. It indicated that participants who were or who had previously been shiftworkers (i.e., working schedules that involved rotating shifts; not being able to go to bed before midnight; having to get up before 05:00h; or being prevented from sleeping during the night) were more likely to exhibit symptoms of metabolic syndrome, after adjusting for age, sex, socioeconomic status, smoking, alcohol intake, perceived stress, and sleep difficulty (odds ratio [OR] 1.78; 95 confidence interval [CI] 1.033.08). The results suggest the association between shiftwork and metabolic syndrome cannot be fully accounted for by either higher levels of strain or increased sleep difficulty among shiftworkers, although it remains a possibility that either one or both of these factors may have played a contributing role. The second analysis addressed the issue of duration of exposure to shiftwork. Participants with >10 yrs' experience of working rotating shifts were more likely to exhibit symptoms of metabolic syndrome than participants without exposure to shiftwork, i.e., dayworkers, even after adjusting for age and sex (OR 1.96; 95 CI 1.033.75). Thus, the current study confirms the association between shiftwork exposure and metabolic syndrome. It also provides new information regarding the time course of the development of the illness as function of exposure duration, although this was only examined in relation to rotating shiftwork. It is concluded that those responsible for monitoring workers' health should pay particular attention to indices of metabolic dysfunction in workers who have been exposed to shiftwork for >10 yrs. (Author correspondence: [email protected] /* */)
    Chronobiology International 06/2012; 29(5):549-55. DOI:10.3109/07420528.2012.675259 · 2.88 Impact Factor
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    • "In addition, sleep deprivation activates the immune system [10] and influences glucose metabolism [11]. Shift work increases the risk of cardiovascular disease (CVD), and possibly also the risks of metabolic syndrome (MetS) and obesity [4] [12] [13]. MetS is known to predispose to the development of T2D and CVD [14]. "
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    ABSTRACT: To assess the risk for type 2 diabetes (T2D) and cardiovascular disease (CVD) among employees of a Finnish airline; to study the association of shift work with T2D and CVD risk; and to test the feasibility of risk screening in occupational health care setting. Altogether 4169 employees were invited for a health check-up and 2312 participated in this study. The check-up included physical examinations, questionnaires on working hours, sleep, and lifestyle, diabetes risk score FINDRISC, and blood tests. Lifestyle counselling was offered for those with increased T2D risk. Altogether 15% of participants had a high T2D risk (FINDRISC≥15 and/or elevated, but non-diabetic blood glucose), and a further 15% had a moderate T2D risk (FINDRISC 10-14 and normal blood glucose). Of those 60% agreed to attend lifestyle counselling. Metabolic syndrome was more common, lipid profile more unfavorable and hsCRP higher by increasing FINDRISC score category. Risk factor profiles linked to shift work status were not self-evident. The renewed health check-up process effectively identified those employees with increased T2D and CVD risk who would benefit from lifestyle intervention. The use of FINDRISC questionnaire was a feasible first-step screening method in occupational health care setting.
    02/2012; 6(2):95-102. DOI:10.1016/j.pcd.2012.01.003
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    • "Sleep disorders due to shift work or because of other reasons have been associated with obesity [6], metabolic syndrome [7] as well as with CVDs; with elevated blood pressures (8-10), coronary artery disease (CAD) [4] [11] [12] [13] [14] [15] [16] [17] [18] and decreased heart rate variability (HRV). Decline in HRV may increase the long-term risk of cardiovascular mortality and morbidity [2] [3] [4] [8] [14] [15] [16] [17]. Shift work is affecting 20% to 25% of employees and is becoming increasingly prevalent in contemporary life all over the industrialized world [7]. "
    World Heart Journal 01/2012; 4(1):23-34.
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