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Original article
Scand J Work Environ Health 2011;37(5):376-382
doi:10.5271/sjweh.3167
Sickness absence associated with shared and open-plan
offices – a national cross sectional questionnaire survey
by Pejtersen JH, Feveile H, Christensen KB, Burr H
Affiliation: Danish National Centre for Social Research, Herluf
Trolles Gade 11,·DK-1052 Copenhagen K, Denmark. jhp@sfi.dk
The following article refers to this text: 2011;37(5):359-362
Key terms: office building; open-plan office; shared office; sick leave;
sickness absence; work environment
This article in PubMed: www.ncbi.nlm.nih.gov/pubmed/21528171
376 Scand J Work Environ Health 2011, vol 37, no 5
Original article
Scand J Work Environ Health 2011;37(5):376–382. doi:10.5271/sjweh.3167
Sickness absence associated with shared and open-plan offices – a national
cross sectional questionnaire survey
by Jan H Pejtersen, PhD,1 Helene Feveile, PhD,1 Karl B Christensen, PhD,2 Hermann Burr, PhD 1
Pejtersen JH, Feveile H, Christensen KB, Burr H. Sickness absence associated with shared and open-plan offices –
a national cross sectional questionnaire survey. Scand J Work Environ Health 2011;37(5):376–382. doi:10.5271/
sjweh.3167
Objective The aim of this study was to examine whether shared and open-plan offices are associated with more
days of sickness absence than cellular offices comprising one occupant.
Methods The analysis was based on a national survey of Danish inhabitants between 18–59 years of age
(response rate 62%), and the study population consisted of the 2403 employees that reported working in offices.
The different types of offices were characterized according to self-reported number of occupants in the space.
The log-linear Poisson model was used to model the number of self-reported sickness absence days depending
on the type of office; the analysis was adjusted for age, gender, socioeconomic status, body mass index, alcohol
consumption, smoking habits, and physical activity during leisure time.
Results Sickness absence was significantly related to having a greater number of occupants in the office
(P<0.001) when adjusting for confounders. Compared to cellular offices, occupants in 2-person offices had 50%
more days of sickness absence [rate ratio (RR) 1.50, 95% confidence interval (95% CI) 1.13–1.98], occupants
in 3–6-person offices had 36% more days of sickness absence (RR 1.36, 95% CI 1.08–1.73), and occupants in
open-plan offices (>6 persons) had 62% more days of sickness absence (RR 1.62, 95% CI 1.30–2.02).
Conclusion Occupants sharing an office and occupants in open-plan offices (>6 occupants) had significantly
more days of sickness absence than occupants in cellular offices.
Key terms office building; sick leave; work environment.
1 National Research Centre for the Working Environment, Copenhagen, Denmark.
2 Institute of Public Health, Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark.
Correspondence to: Jan H Pejtersen, Danish National Centre for Social Research, Herluf Trolles Gade 11,·DK-1052, Copenhagen K,
Denmark. [E-mail:jhp@sfi.dk].
Sickness absence is an important public health problem
with an impact on employees, the employer, and society
in general (1–3). Risk factors for sickness absence have
been the topic of many studies (4), but so far only a few
have related sickness absence to the indoor environ-
ment in offices (5). Danielsson & Bodin (6) studied the
association between self-reported sick leave and type
of office characterized by a combination of functional
features of the offices and number of occupants. The
type of office showed no association with the risk of
sick leave (>7 days/year), but an association between the
type of office and being sick at least one day per year
was found. Sharing an office has shown to be a risk fac-
tor for more than two epi sodes of common cold during a
year compared to workers having private offices (7). In
an observa tional study, Milton et al (8) found an asso-
ciation between sickness absence and lower ventilation
rates per person in offices. However, in an experimental
intervention study, no relation between ventilation rate
and sick leave was found (9).
Studies have found that sickness absence was associ-
ated with mechani cal ventilation (10) and air-condition-
ing (11), and cleaning the ventilation system may reduce
the prevalence of symptoms and the absenteeism rate
(5). Mechanical ventilation has been associated with
an elevated prevalence of non-specific symptoms in
office buildings in several studies (12, 13); open-plan
offices are more likely to have mechanical ventilation
than cellular offices to be able to cope with build ing
regulations (14).
We have previously reported that the prevalence
of indoor environmental complaints and non-speci fic
Scand J Work Environ Health 2011, vol 37, no 5 377
Pejtersen et al
symptoms among office workers increased with an
increasing number of occupants in the space (14). How-
ever, in a review of non-specific symptoms among office
workers, only 7 out of 32 studies included the number
of office workers in the space (12). Five of these found
the number of office workers to be positively associated
with prevalence of symptoms. This is in accordance with
recent studies (7, 15–18).
The most prevalent complaint in open-plan offices is
noise annoyance (14, 19), with ringing phones and other
peoples’ conversation being the most annoying sources
of noise (20). In open-plan offices, employees perceive
they have less privacy and find it difficult to have undis-
turbed and confidential conversations (21). However, to
our knowledge, no studies have related noise to sickness
absence solely in office buildings.
Several studies have found that psychosocial risk
factors predict sickness absence (22–24). One of these
has been performed among office workers but did not
include the number of workers per office (24). In our pre-
vious study, we found a significant association between
employees’ psychosocial work environment and the type
of office for a number of psychosocial dimensions (14),
but differences were below what is regarded as mean-
ingful (25). However, a review found strong evidence
that working in open-plan offices reduced employees’
privacy and job satisfaction (19).
The aim of this study was to investigate whether
shared and open-plan offices were associated with a
higher number of days of sickness absence than cellular
offices.
Methods
This study is based on the 2005 wave of the Danish
Work Environment Cohort Study (DWECS) (26). The
main components of DWECS are cohorts of random
samples of adults registered in the Danish centralized
civil register (CRS).
The analysis is based on a representative sample
of Danish inhabitants, who had not requested survey
exemption (27), were between 18–59 years of age,
and were assigned to receive a mailed questionnaire.
Respondents who had been employees within two
months prior to the survey were classified as employees
and responded to questions about working conditions
and health behavior. The sample consisted of 14 969
persons of which 9252 participated (62%), 7219 of these
were employees. This study is based on the 2403 (33%
of the 7219) employees that reported working in offices
most of their time at work.
Type of workplace was assessed with the question
“Where do you spend most of your time at work?”
Response options were: (i) outside; (ii) vehicle (for
example, car, truck, work machine, train, ship); (iii)
workshop or production area, with ___ colleagues (indi-
cate how many); (iv) workshop, production area without
colleagues; (v) location where there are customers,
clients, patients, students, children; (vi) office or open-
plan office (multiple workers in the same space), with
___ colleagues (indicate how many); (vii) office without
colleagues; (viii) indoors, other, indicate what:___.
Respondents were classified as working in offices if
they used the 7th response category or the 6th response
category together with a response to the question about
number of colleagues.
Office workers were divided into four categories
according to type of office: (i) cellular offices compris-
ing one occupant, (ii) shared offices comprising two
occupants, (iii) shared offices comprising three to six
occupants, and (iv) open-plan offices comprising more
than six occupants.
Sickness absence was assessed with the question
“In total, how many sick days have you taken in the last
year? Number of days: ___”.
Body mass index (BMI) was calculated from self-
reported weight and height and categorized according
to the standard classification of the World Health Orga-
nization (WHO) (28). The population was divided into
heavy smokers (≥15 cigarettes/day), moderate smokers
(<15 cigarettes/day), ex-smokers and non-smokers. Men
were classified as having a high consumption of alcohol
if their consumption on aver age exceeded three units per
day. Women were classified as high consumers if they on
average re ported more than two units per day.
Physical activity during leisure time in the last year
was measured with a single question (29). The four
response categories were: (i) physically inactive/light
physical activity <2 hours per week; (ii) light physical
activity 2–4 hours per week; (iii) physically active ≥4
hours per week or more vigorous physical activity 2–4
hours per week; (iv) more vigorous physical activity
and competitive sports several times per week (>4 hours
per week).
Socioeconomic status was divided into six classes
based on self-reported information on employ ment
grade, job title, and education (30).
The distributions of age, gender, socioeconomic
status, BMI, alcohol consumption, smoking habits, and
physical activity during leisure time according to the
various types of offices are given in table 1. Among the
respondents working in offices, 2308 (96 %) answered
the question concerning sickness absence. As sickness
absence is a rare event, Poisson regression was used
to model the number of self-reported sickness absence
days. The analysis was adjusted for age, gender, socio-
economic status, BMI, alcohol consumption, smoking
habits and physical activity during leisure time (31, 32)
378 Scand J Work Environ Health 2011, vol 37, no 5
Sickness absence in offices
and a scale parameter was added to account for over-
dispersion. A total number of 2202 respondents with
non-missing data entered in this analysis.
Results
The average and median number of days of absence
from work due to sickness during the last year for the
occupants in the various types of offices is shown in
table 2. The occupants in shared or open-plan offices
reported almost twice as many days of sickness absence
compared to occupants in private offices.
The rate ratios (RR) for sickness absence in the vari-
ous office types are shown in table 3. Sickness absence
was significantly related to type of office when adjust-
ing for age, gender, socioeconomic status, BMI, alcohol
consumption, smoking habits, and physical activity
during leisure time (P<0.001). The occupants in 2- and
3–6-person offices had on average, respectively 50%
and 36% more days of sickness absence than occupants
in cellular offices, while the occupants in open-plan
offices (>6 persons) had on average 62% more days
of sickness absence than occupants in cellular offices.
Discussion
The strength of this study is the use of a national popu-
lation sample. In contrast to other studies of open-plan
offices (6, 14), this study represents more than 2000 dif-
ferent offices. To our knowledge this is the first national
population study that has related sickness absence to
type of office.
A weakness of the study is that both the type of
office classification and sickness absence are based on
self-report and associations may be influenced by com-
mon method bias (33). Reporting of sickness absence
during the last 12 months may be influenced by recall
bias (34), but the reporting of the number of occupants
in the space is less likely to be affected by memory. The
distribution of the number of occupants in the space
(data not shown), showed that the reporting was subject
to end-digit preference above ten occupants (35). This
Table 1. Characteristic of the study population in the various office types. [SD=standard deviation.]
Characteristic Office type [number of occupants]
1 (N=543) 2 (N=268) 3–6 (N=637) >6 (N=955) Total (N=2403)
% Mean SD % Mean SD % Mean SD % Mean SD % Mean SD
Age (years) 146.0 9.2 42.6 9.1 41.0 9.8 41.1 10.1 42.4 9.9
Gender (women) 53 66 60 50 55
Socioeconomic status
Higher white-collar 47 35 28 32 35
Middle white-collar 25 22 21 20 21
Lower white-collar 22 34 42 40 36
Skilled workers 3 7 4 5 4
Unskilled workers 4 2 2 2 2
In process of training 0 0 2 2 1
Body mass index (BMI)
<18.5 (underweight) 1 2 1 2 1
18.5–24.9 (normal) 54 60 59 60 59
25–29.9 (over weight) 36 31 29 31 32
≥30 (obese) 9 7 10 7 8
Smoking habits
Non-smokers 43 49 50 51 49
Ex-smokers 34 28 26 28 29
Moderate smokers (<15 cigarettes/day) 9 12 11 12 11
Heavy smokers (≥15 cigarettes/day) 15 10 13 9 9
Alcohol consumption
High consumption (men: >3 units per day;
women: >2 units per day)
16 13 16 15 15
Physical activity during leisure time
Physically active <2 hours/week 18 16 17 17 17
Light physical activity 2–4 hours/week 58 63 59 58 58
Physically active >4 hours/week or more
vigorous physical activity 2–4 hours/week
22 18 21 22 22
More vigorous physical activity and competitive
sports several times per week, >4 hours per week
3 3 3 3 3
1 Age, November 2005
Scand J Work Environ Health 2011, vol 37, no 5 379
Pejtersen et al
may be because respondents in larger offices pass from
actually counting to roughly estimating the number of
colleagues in the offices. Except for the end-digit pref-
erence peaks, the distribution was very similar to our
previous study where the occupants were counted by
a researcher (data not shown) (14). This indicates that
the self-reported number of occupants <10 is valid, and
since the offices were categorized into 1-, 2-, 3–6- and
>6-person offices, the bias in relation to the end-digit
preference had no influence on the found association.
Another weakness is that we do not know if the
occupants have been in the same office for the entire
recall period of 12 months. However, adjusting the
model for length of employment in the company did
not change the estimated rate ratios (data not shown).
Although employees may change office within the
company, we have no reason to believe that this should
bias the results.
In all, 2308 respondents answered the question
about sickness absence (table 2), but due to missing
values for some of the covariates our analysis is based
on 2202 occupants (table 3). The mean number of sick-
ness absence days is higher for the group with missing
data on covariates, but the pattern and relations between
office categories are very similar to the overall sample
(table 2). We do not think that the 4.5% missing data
could influence the conclusion.
It would have been an advantage to have matched
workplaces in each of the four categories of offices.
However, by taking a random sample of employees, we
are accounting for the fact that there is no matching on
workplaces. Furthermore, by focusing on office workers,
we are making the type of work comparable and also
excluding workplaces and industries where employees
experience sickness absence due to hard manual work
etc. To further study this, we adjusted our model for
differences in industries by using the 9-grouping for
standard industrial grouping according to the 2003
Danish industrial classification of all economic activi-
ties (data not shown). We collapsed some of the smaller
categories. The adjustment for industrial grouping had
very little effect on the RR as they were reduced by
only 2–4%.
The validity of self-reported sickness absence has
been studied among British civil servants, who mainly
were office workers. The study found good agreement
between self-reported sickness absence and register-
based sickness absence (36). The mean absence rates for
the British civil servants were 7.1 days per year based
on self-reported data and 7.3 days per year based on
recorded data. This is similar to the mean absence rate
of 7.1 days per year in our study. We therefore believe
that self-reported sickness absence is a valid measure.
In Danish national surveys, there are increasing
proportions of non-responders especially among young
persons, and survey exception is four times more com-
mon among the age group 20–29 years than in the age
group 50–59 years (27). In this study, we saw a slight
trend towards decreasing age with increasing number
of occupants in the space (table 1), and as other stud-
ies have shown that increasing age were a risk factor
for self-reported sickness absence (31), we have age-
adjusted the analysis. Nevertheless, we might have
problems concerning the representativeness of the young
responders if the non-responders and those with survey
exception differ from respondents when it comes to both
type of office and self-reported sickness absence. Per-
sons with higher education are least inclined to request
survey exemption (27) and non-responders have lower
socioeconomic status and worse health than responders
according to a Danish population-based study (37). The
under-representation of the age group 20–29 years most
likely resulted in bias towards an underestimation of the
association, assuming that lower socioeconomic status is
associated with more occupants in the office.
This study is cross-sectional and cannot explain the
mechanisms behind the increased sickness absence rates
in shared and open-plan offices. However, the literature
suggests five main explanations. One explanation could
be that increased absence rates in shared and open-
plan offices are caused by higher exposure to noise in
these offices (14). In their review, Passchier-Vermeer
& Passchier (38) found that exposure to noise indoors
constitutes a risk in terms of hearing impairment, hyper-
tension, annoyance and sleep disturbance, but there was
limited evidence that absence rates were related to noise
exposure. Evans (39) found elevated stress hormone in
Table 2. Self-reported days of sickness absence within the last
year according to office types.
Office type
[number of
occupants]
N Days of sickness
absence
(mean)
Days of sickness
absence
(median)
1 522 4.9 1.0
2 258 8.0 2.0
3–6 610 7.1 2.0
>6 918 8.1 2.0
Table 3. Rate ratios for sickness absence in the various office
types. The log-linear Poisson model was adjusted for age, gen-
der, socioeconomic status, body mass index, alcohol consump-
tion, smoking habits and physical activity during leisure time.
[95% CI=95% confidence interval.]
Office type [number
of occupants]
N Rate ratios 95% CI
1 497 1
2 250 1.50 1.13–1.98
3–6 584 1.36 1.08–1.73
>6 871 1.62 1.30–2.02
380 Scand J Work Environ Health 2011, vol 37, no 5
Sickness absence in offices
subjects exposed to office noise compared to subjects
exposed to quiet conditions even when there were no
differences in the subjects’ perception of stress. Clausen
et al (40) found a relation between self-reported noise
exposure and long-term sickness absence for men, but
not for women. Although the results from other studies
are mixed, noise exposure is more prevalent in shared
and especially open-plan offices and may be a part of
the explanation for the found association.
Another explanation for the association could be
that the difference in sickness absence in the various
offices is due to differences in the type of ventilation
used. Open-plan offices are in general equipped with
mechanical ventilation whereas many cellular offices in
Denmark have natural ventilation (14). This explanation
is supported by other studies (10, 11) and the general
finding that mechanical ventilation is associated with
non-specific symptoms (12, 13). However, controlling
for type of ventilation in our previous study did not
remove the effect of type of office on symptoms (14).
A third explanation for the found association could
be that occupants in shared and open-plan offices are
more likely to be exposed to viruses than occupants
in cellular offices. A recent review showed strong evi-
dence for an association between ventilation, air move-
ments in buildings, and the spread of infectious diseases
(41). Even though the number of sources is higher in
mechanically ventilated open-plan offices than in natu-
rally ventilated cellular offices, the ventilation rate is in
general also higher in open-plan offices, so the resulting
exposure for workers in the various types of offices is
hard to estimate.
A fourth explanation for the difference in sickness
absence between types of offices could be differences in
the psychosocial work environment (23). Our previous
study neither supported nor contradicted this explana-
tion since we found statistically significant differences
in the psychosocial work environment between offices,
but the magnitude of the differences was very modest
(14). Other studies pointed at lack of privacy as a severe
problem in open-plan offices (19).
A final explanation has to do with the presence of
other humans when working, and shares similarities with
the psychosocial explanation. Working in open-plan or
shared offices may reduce employees’ autonomy, as the
absence of physical boundaries will increase the likeli-
hood that co-workers and leaders will interfere with
the employees’ discretion and freedom to work (19).
Lack of autonomy may be a stressor, as it is related to
burnout (42), and therefore can be a contributing factor
to sickness absence. Related to this explanation is the
evaluation apprehension explanation. Within psychol-
ogy, studies have shown that working in the presence
of others may lead to social facilitation, however if the
employees are subject to evaluation apprehension, this
may rather lead to inhibition than social facilitation (43).
This stressor may therefore also be a contributing factor
to sickness absence.
Concluding remarks
Open-plan offices have become popular because they are
designed to facilitate communication and accommodate
knowledge sharing. However, our study showed that
occupants sharing an office had a significantly higher
number of days of sickness absence than those in cel-
lular offices. Consequently, employees, employers, and
society in general pay a high price for the benefits of
open-plan offices in terms of sickness absence and loss
of productivity.
Acknowledgements
This work was partly supported by the Danish Ministry
of Employment as a part of a surveillance programme on
occupational health, and partly by the Danish Working
Environment Research Fund [Grant no: 20070014615].
References
1. Whitaker SC. The management of sickness absence. Occup
Environ Med. 2001;58:420-4.
doi:10.1136/oem.58.6.420.
2. Gimeno D, Benavides FG, Benach J, Amick BC. Distribution
of sickness absence in the European Union countries. Occup
Environ Med. 2004;61:867-9.
doi:10.1136/oem.2003.010074.
3. Henderson M, Glozier N, Holland Elliott K. Long term
sickness absence. BMJ. 2005;330:802-3.
doi:10.1136/
bmj.330.7495.802.
4. Allebeck P, Mastekaasa A. Chapter 5. Risk factors for sick
leave - general studies. Scand J Public Health. 2004;32:49-108.
doi:10.1080/14034950410021853.
5. Niemelä R, Seppänen O, Korhonen P, Reijula K. Prevalence
of building-related symptoms as an indicator of health and
productivity. Am J Ind Med. 2006;49:819-25.
doi:10.1002/
ajim.20370.
6. Danielsson CB, Bodin L. Office type in relation to health, well-
being, and job satisfaction among employees. Environ Behav.
2008;40:636-68.
doi:10.1177/0013916507307459.
7. Jaakkola JJK, Heinonen OP. Shared office space and the
risk of the common cold. Eur J Epidemiol. 1995;11:213-6.
doi:10.1007/BF01719490.
8. Milton DK, Glencross PM, Walters MD. Risk of Sick Leave
Associated with Outdoor Air Supply Rate, Humidification,
and Occupant Complaints. Indoor Air. 2000;10:212-21.
doi:10.1034/j.1600-0668.2000.010004212.x.
9. Myatt TA, Staudenmayer J, Adams K, Walters M, Rudnick
Scand J Work Environ Health 2011, vol 37, no 5 381
Pejtersen et al
SN, Milton DK. A study of indoor carbon dioxide levels and
sick leave among office workers. Environ Health. 2002;1:3.
doi:10.1186/1476-069X-1-3.
10. Preziosi P, Czernichow S, Gehanno P, Hercberg S. Workplace
air-conditioning and health services attendance among
French middle-aged women: a prospective cohort study. Int J
Epidemiol. 2004;33:1120-3.
doi:10.1093/ije/dyh136.
11. Teculescu DB, Sauleau EA, Massin N, Bohadana AB,
Buhler O, Benamghar L, Mur JM. Sick-building symptoms
in office workers in northeastern France: a pilot study. Int
Arch Occup Environ Health. 1998;71:353-6.
doi:10.1007/
s004200050292.
12. Mendell MJ. Non-specific symptoms in office workers: A
review and summary of the epidemiologic literature. Indoor
Air. 1993;3:227-36.
doi:10.1111/j.1600-0668.1993.00003.x.
13. Seppänen O, Fisk WJ. Association of ventilation system type
with SBS symptoms in office workers. Indoor Air. 2002;12:98-
112.
doi:10.1034/j.1600-0668.2002.01111.x.
14. Pejtersen J, Allermann L, Kristensen TS, Poulsen OM. Indoor
climate, psychosocial work environment and symptoms in
open-plan offices. Indoor Air. 2006;16:392-401.
doi:10.1111/
j.1600-0668.2006.00444.x
15. Fisk WJ, Mendell MJ, Daisey JM, Faulkner D, Hodgson AT,
Nematollahi M, Machin D. Phase1 of the California healthy
building study: a summary. Indoor Air. 1993;3:246-54.
doi:10.1111/j.1600-0668.1993.00005.x.
16. Stenberg B, Mild KH, Sandstrom M, Sundell J, Wall S. A
prevalence study of the sick building syndrome (SBS) and
facial skin symptoms in office workers. Indoor Air. 1993;3:71-
81.
doi:10.1111/j.1600-0668.1993.t01-2-00002.x.
17. Menzies R, Tamblyn R, Farant JP, Hanley J, Nunes F,
Tamblyn R. The effect of varying levels of outdoor-air supply
on the symptoms of sick building syndrome. N Engl J Med.
1993;328:821-7.
doi:10.1056/NEJM199303253281201.
18. Chao HJ, Schwartz J, Milton DK, Burge HA. The work
environment and workers’ health in four large office buildings.
Environ Health Perspect. 2003;111:1242-8.
doi:10.1289/
ehp.5697.
19. De Croon EM, Sluiter JK, Kuijer PPFM, Frings-Dresen
MHW. The effect of office concepts on worker health
and performance: a systematic review of the literature.
Ergonomics. 2005;48:119-34.
doi:10.1080/0014013051233
1319409.
20. Banbury SP, Berry DC. Office noise and employee
concentration: Identifying causes of disruption and potential
improvements. Ergonomics. 2005;48:25-37.
doi:10.1080/00
140130412331311390.
21. Brennan A, Chugh JS, Kline T. Traditional versus open
office design. A longitudinal field study. Environ Behav.
2002;34:279-99.
doi:10.1177/0013916502034003001.
22. Alexanderson K. Sickness absence: a review of performed
studies with focused on levels of exposures and theories
utilized. Scand J Soc Med. 1998;26:241-9.
23. Duijts SFA, Kant J, Swaen GMH, van den Brandt PA,
Zeegers MPA. A meta-analysis of observational studies
identifies predictors of sickness absence. J Clin Epidemiol.
2007;60:1105-15.
doi:10.1016/j.jclinepi.2007.04.008.
24. North FM, Syme SL, Feeney A, Shipley M, Marmot M.
Psychosocial work environment and sickness absence among
British civil servants: The Whitehall II Study. Am J Public
Health. 1996;86:332-40.
doi:10.2105/AJPH.86.3.332.
25. Pejtersen JH, Bjorner JB, Hasle P. Determining minimally
important score differences in scales of the Copenhagen
Psychosocial Questionnaire. Scand J Public Health.
2010;38:33-41.
doi:10.1177/1403494809347024.
26. Feveile H, Olsen O, Burr H, Bach E. Danish work environment
cohort study 2005: from idea to sampling design. Statistics in
Transition - new series. 2007;8:441-58.
27. Thorsted, BL. Forskerbeskyttelse i CPR. Survey exemption
in the Danish Centralized Civil Register. In: Linde, P., editor.
Århus University: Statistic Denmark; 2007. p74-84.
28. WHO. Obesity: preventing and managing the global epidemic.
Report of a WHO Consultation. Geneva: World Health
Organization; 2000. WHO Technical Report Series No. 894.
29. Saltin B, Grimby G. Physiological Analysis of Middle-Aged
and Old Former Athletes - Comparison with Still Active
Athletes of Same Ages. Circulation. 1968;38:1104-15.
30. Borg V, Kristensen TS, Burr H. Work environment and
changes in self-rated health: a five year follow-up study.
Stress Med. 2000;16:37-47.
doi:10.1002/(SICI)1099-
1700(200001)16:1<37::AID-SMI830>3.0.CO;2-O.
31. Labriola M, Lund T, Burr H. Prospective study of physical and
psychosocial risk factors for sickness absence. Occup Med.
2006;56:469-74.
doi:10.1093/occmed/kql058.
32. Christensen KB, Labriola M, Lund T, Kivimäki M. Explaining
the social gradient in long-term sickness absence: a prospective
study of Danish employees. J Epidemiol Community Health.
2008;62:181-3.
doi:10.1136/jech.2006.056135.
33. Podsakoff PM, MacKenzie SB, Lee JY, Podsakoff NP.
Common method biases in behavioral research: A critical
review of the literature and recommended remedies. J Appl
Psychol. 2003;88:879-903.
doi:10.1037/0021-9010.88.5.879.
34. Bradburn NM, Rips LJ, Shevell SK. Answering
Autobiographical Questions - the Impact of Memory and
Inference on Surveys. Science. 1987;236:157-61.
doi:10.1126/
science.3563494.
35. Camarda CG, Eilers PHC, Gampe J. Modelling general
patterns of digit preference. Stat Modelling. 2008;8:385-401.
doi:10.1177/1471082X0800800404.
36. Ferrie JE, Kivimaki M, Head J, Shipley MJ, Vahtera J, Marmot
MG. A comparison of self-reported sickness absence with
absences recorded in employers’ registers: evidence from
the Whitehall II study. Occup Environ Med. 2005;62:74-9.
doi:10.1136/oem.2004.013896.
37. Drivsholm T, Eplov LF, Davidsen M, Jorgensen T, Ibsen
H, Hollnagel H, Borch-Johnsen K. Representativeness in
population-based studies: A detailed description of non-
response in a Danish cohort study. Scand J Public Health.
2006;34:623-31.
doi:10.1080/14034940600607616.
38. Passchier-Vermeer W, Passchier WF. Noise exposure and
382 Scand J Work Environ Health 2011, vol 37, no 5
Sickness absence in offices
public health. Environ Health Perspect. 2000;108:123-31.
doi:10.2307/3454637.
39. Evans GW, Johnson D. Stress and open-office noise. J Appl
Psychol. 2000;85:779-83.
doi:10.1037/0021-9010.85.5.779.
40. Clausen T, Christensen KB, Lund T, Kristiansen J. Self-
reported noise exposure as a risk factor for long-term sickness
absence. Noise Health. 2009;11:93-7.
doi:10.4103/1463-
1741.50693.
41. Li Y, Leung GM, Tang JW, Yang X, Chao CYH, Lin JZ, Lu JW,
Nielsen PV, Niu J, Qian H, Sleigh AC, Su HJJ, Sundell J, Wong
TW, Yuen PL. Role of ventilation in airborne transmission of
infectious agents in the built environment - a multidisciplinary
systematic review. Indoor Air. 2007;17:2-18.
doi:10.1111/
j.1600-0668.2006.00445.x.
42. Lee RT, Ashforth BE. A meta-analytic examination of the
correlates of the three dimensions of job burnout. J Appl
Psychol. 1996;81:123-33.
doi:10.1037/0021-9010.81.2.123.
43. Feinberg JM, Aiello JR. Social facilitation: A test of competing
theories. Journal of Applied Social Psychology. 2006;36:1087-
109.
doi:10.1111/j.0021-9029.2006.00032.x.
Received for publication: 23 December 2010