Change search
ReferencesLink to record
Permanent link

Direct link
Total mortality and cause-specific mortality of Swedish shift- and dayworkers in the pulp and paper industry in 1952-2001.
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
Show others and affiliations
2005 (English)In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, Vol. 31, no 1, 30-35 p.Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: The study investigated the relationship between shiftwork and mortality, both total mortality and cause-specific mortality from coronary heart disease (CHD), stroke, and diabetes. Methods The cohort consisted of 2354 shiftworkers and 3088 dayworkers in two pulp and paper manufacturing plants. The mortality of the cohort was monitored from 1 January 1952 to 31 December 2001 by linkage to the national Cause of Death Register. Groups of workers defined by different durations of shiftwork exposure were compared with dayworkers by calculating standardized relative rates (SRR). RESULTS: Death due to any cause (total mortality) was not higher among the shiftworkers than among the dayworkers [SRR 1.02, 95% confidence interval (95% CI) 0.93-1.11]. A longer duration of shiftwork was associated with an increased risk of CHD, and shiftworkers with >30 years of shiftwork had the highest risk of CHD (SRR 1.24, 95% CI 1.04-1.49) Diabetes was more common as the number of shift years of exposure increased [b(linear coefficient) = 4.14 x 10(-5), 95% CI 2.46 x 10(-5) -5.81 x 10(-5)]. Compared with dayworkers, shiftworkers had a greater risk of death due to stroke (SRR 1.56, 95% CI 0.98-2.51). CONCLUSIONS: In the present study, no general increase in mortality was observed among shiftworkers when they were compared with dayworkers. However, the results demonstrate an increased mortality from CHD among shiftworkers with a long duration of shiftwork exposure. Mortality due to diabetes also increased as the number of shift years and mortality due to ischemic stroke in shiftworkers increased.

Place, publisher, year, edition, pages
2005. Vol. 31, no 1, 30-35 p.
Keyword [en]
Adolescent, Adult, Age Distribution, Cerebrovascular Accident/*mortality, Child, Cohort Studies, Coronary Disease/*mortality, Diabetes Mellitus/*mortality, Humans, Male, Middle Aged, Occupational Health, Paper, Sweden/epidemiology, Work Schedule Tolerance
National Category
Medical and Health Sciences
URN: urn:nbn:se:umu:diva-18085PubMedID: 15751616OAI: diva2:157758
Available from: 2007-12-06 Created: 2007-12-06 Last updated: 2010-08-02Bibliographically approved
In thesis
1. Metabolic disturbances in shift workers
Open this publication in new window or tab >>Metabolic disturbances in shift workers
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

An increased risk for coronary heart disease among shift workers is earlier shown in the epidemiological literature. The aim of this thesis has been to penetrate metabolic disturbances and obesity among shift workers compared to day workers, and to compare if there are differences in total mortality or cause specific mortality of coronary heart disease (CHD), diabetes or ischaemic stroke in between the two groups.

In an intervention study on female nurses (N=11), on night schedules in Umeå hospital, the highest peak value of glucose and insulin after meal ingestion was seen in the late evening (23:30). The post-prandial area under curve (AUC) of glucose and insulin was correspondingly largest after meal ingestion the same clock hour compared to meal ingestion other clock times.

In two different cross-sectional studies Västerbotten Inventory Study (VIP) (N= 27,485) and in a subset of Work, Lipids and Fibrinogen Study (WOLF) (N= 1,324) metabolic differences in between shift and day workers has been evaluated. In both studies have obesity, high triglycerides and low HDL-cholesterol been more prevalent among the shift-working group compared to the day-working group. After adjustments for age and socio-economic factors in the VIP-study obesity and high triglycerides remained as risk factors in shift workers in both men and women. After directly age standardisation, a clustering effect, simultaneously, of two or more metabolic risk factors (obesity, hypertension, and high triglycerides) was seen in both genders among the shift workers compared to the day workers. Correspondingly, in the Wolf study low HDL-cholesterol and high triglycerides remained as significant risk factors after adjustments of confounders as age, socio-economic group, physical activity, current smoking, low social support and high job strain.

In a cohort study from one company (MoDo) with two plants in the pulp and paper industry 2,354 male shift workers and 3,088 male day workers were followed from January 1, 1952 to December 31, 2001 regarding total and cause specific mortality due to CHD, diabetes and ischaemic stroke. Groups of workers defined by different duration of shift exposure were compared with day workers by calculating standardised relative rates (SRR). No increased risk of total mortality was seen among shift workers compared to day workers. Higher duration of shift work was associated with increased risk for CHD, and shift workers with 30 years or more had the highest risk. Diabetes was more common with increasing number of shift year exposure. Compared to day workers shift workers had also an increased risk to die because of ischaemic stroke, with the highest relative difference in the least shift exposed group (< 5 years).

55 p.
Umeå University medical dissertations, ISSN 0346-6612
shift work, epidemiology, mortality, diabetes, stroke, coronary heart disease, obesity, triglycerides, HDL-cholesterol, insulin, glucose
Research subject
Occupational and Environmental Medicine
urn:nbn:se:umu:diva-242 (URN)91-7305-643-X (ISBN)
Public defence
2004-05-14, Sal B, 9 tr, Tandläkarhögskolan i Umeå, Norrlands Universitetssjukhus, 09:00
Available from: 2004-04-20 Created: 2004-04-20 Last updated: 2010-08-02Bibliographically approved

Open Access in DiVA

No full text

Other links


Search in DiVA

By author/editor
Karlsson, Berndt
By organisation
Occupational and Environmental Medicine
In the same journal
Scandinavian Journal of Work, Environment and Health
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 120 hits
ReferencesLink to record
Permanent link

Direct link