SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science II. Sleep Disorders – Circadian Rhythms
Conclusion: DSPD risk is associated with increased absenteeism and
impaired functioning in work/school, social and family life.
Support (If Any): This study was funded by Vanda Pharmaceuticals
Inc.
0476
HEALTH AND PSYCHOLOGICAL VARIABLES RELATED TO
INSOMNIA IN SHIFT WORKERS
Vallieres A 1,2,3 , Moreau V 1,2 , LeBlanc M 1,2 , Morin CM 1,2
1
Ecole de psychologie, Universite Laval, Quebec, QC, Canada, 2 Centre
d’etude des troubles du sommeil, Centre de recherche Universite
Laval-Robert Giffard, Quebec, QC, Canada, 3 Centre de recherche du
CHUQ, Quebec, QC, Canada
Introduction: The contribution of insomnia in the context of shift work
on physical and psychological health is poorly documented. The present
study aims at assessing the contribution of insomnia on perceived health,
psychological variables, and life style habits of night and rotating shift
workers compared to day workers.
Methods: 418 adults (51% of women; age, M = 41.4 years old) including
50 night workers, 163 rotating night shift workers, and 213
day workers were selected from an epidemiological study. Each rotating
shift worker and night worker was paired with a day worker based
on gender, age, income, and presence of insomnia. The three groups of
workers were further classified into presence or absence of insomnia
symptoms groups. Participants completed self-reported questionnaires
about sleep, psychological, and health variables.
Results: Among the no insomnia group, night and rotating shift workers
presented a poorer sleep quality than day workers (F(2,412) = 6.2, p
= .002). Apart from sleep quality, night and rotating shift workers with
insomnia were not significantly different than day workers with insomnia
on all psychological and health-related variables. Indeed, individual
with insomnia slept significantly less (F(1,407) = 27.7 , p < .001), had
more wake time (F(1,403) = 77.1 , p < .001), more severe insomnia
(F(1,412) = 201.6 , p < .0001), and more dysfunctional beliefs about
sleep (F(1,411) = 25.4, p < .001) than good sleepers regardless of their
work schedule. Moreover, individuals with insomnia presented higher
levels of anxiety, depression, and lower quality of life than individuals
without insomnia. Life style habits were similar among the three groups
of workers, except for alcohol and cigarettes. Day workers reported
drinking more alcohol (F(2,348) = 5.7, p < .01), while night workers
with insomnia reported smoking more (F(2,409) = 5.0, p = .007). Last,
workers with insomnia were more at risk of suffering from chronic pain
independently of their work schedule (OR = 3.1, p = .002).
Conclusion: This study suggests that insomnia, rather than shift work,
may better explained several negative consequences usually associated
with shift work. Sleep quality seems directly related to shift work. These
results underline the importance of addressing insomnia symptoms in
shift work. Further research remains warranted to specify the contribution
of sleepiness for each group of workers.
Support (If Any): Research supported by the Canadian Institutes of
Health Research (MT42504).
0477
CIRCADIAN PHASE DIFFERENCES IN PATIENTS WITH
SHIFT WORK DISORDER RELATIVE TO ASYMPTOMATIC
SHIFT WORKERS
Drake C, Gumenyuk V, Jefferson C, Roth T
Sleep Disorders & Research Center, Henry Ford Hospital, Detroit, MI,
USA
Introduction: Simulated shift work studies have demonstrated a relationship
between light induced delays in circadian phase and enhanced
adaptation to a shift work schedule including improvements in performance
and sleep. It is not know if individuals with shift work disorder
(SWD) have phase differences relative to asymptomatic shift workers.
The present study used 24-hr dim light melatonin profiles to test for
phase differences between patients diagnosed with SWD compared to
asymptomatic shift workers.
Methods: All subjects were currently working the night shift (~1900-
0800). Five patients diagnosed with SWD (2M; mean age: 35.6±8.6 yrs;
mean yrs on shift = 8.4) and 5 asymptomatic shift workers (2M; mean
age: 39.2±12.6 yrs; mean yrs on shift = 9.3) were screened for other
sleep disorders and studied under dim light (< 10 lux) conditions during
a 25-hr (1700-1800) modified constant routine. Salivary melatonin (30
minute intervals), multiple sleep latency test (13 trials, 2 hour intervals),
and driving simulator performance (5 trials) were assessed. Dim light
melatonin onset (DLMO) was determined using the method of Lee et
al., 2006.
Results: Asymptomatic shift workers had a significantly (p < .001) delayed
DLMO (09:34±3:33) relative to patients with SWD (22:48±2:21).
The MSLT was lower in the SWD patients during night shift hours
2300-0900 (3.95±2.30 vs 7.45±2.76; p = .06). Nocturnal driving simulator
performance was worse in the SWD patients, but did not reach
statistical significance (p > .1).
Conclusion: These findings in workers currently on night shift suggest
a failure to delay the circadian pacemaker in response to shift work contributes
to symptoms of SWD and the presence of physiological sleepiness.
Future studies should explore both intrinsic circadian factors (e.g.,
tau, light sensitivity) and external factors (e.g., light exposure) that may
account for differences in circadian phase between workers with SWD
and asymptomatic shift workers.
Support (If Any): MH082785
0478
INFLUENCES OF SHIFT WORK ON SLEEP - INDUSTRIAL
HEALTH AND SLEEP DISORDERS
Lischewski D 1 , Zimmermann S 1 , Heimlich J 2 , Glos M 1 , Westermayer G 2 ,
Penzel T 1 , Fietze I 1
1
Sleep Medicine Center, Depart. of Cardiology, Charité, University
Hospital, Berlin, Germany, 2 BGF, Gesellschaft für Betriebliche
Gesundheitsförderung mbH, Berlin, Germany
Introduction: Industrial health promotion shall detect the factors in an
organisation which have a positive effect on health and how they can be
used preventively. Aim of this study is the identification of such company
health potentials, which have influences on health and on the sleepwake-rhythm
of shift workers in different companies and shift systems.
Methods: Questionnaires of sleep medicine and work psychology with
the items “work situation”, “exposure/stress”, “health”, “personal attitude”,
“insomnia”, “narcolepsy”, “chronotype” and “Restless-Leg-Syndrome”
ascertained the sleep-wake rhythm of 372 employees and the
individual working conditions in different companies and shift systems.
For the demonstration of the objective effects on sleep we examined the
sleep efficiency (fraction of total sleep time to total time in bed beginning
from turning off the light and final uprising), the length of sleep and
the sleep latency on a subgroup of 137 persons by actigraphy for a period
of 14 days - 24 hours continously - together with a sleep-wake-diary.
Results: In the first interim analysis variables for every person could be
detected, like professional appreciation, possibilities of learning, positive
contact to customers and high identification with work, which can
influence the effects of shift work on health in a positive way. Employees
who are working only in night shifts reported lower tenseness, depletion
and physical impairment than workers in a different shift system. The
sleep latency, total sleep time (in average 6 hours) and sleep efficiency
(< 85%) is for all tested persons lower than in normal population. 46%
showed a clinic prominent fatigue and 30% reported from sleep disorders
and insomnia. Furthermore the persons with insomniac symptoms
showed correlations with more negative perception of working conditions
than persons without these symptoms.
Conclusion: The results leads to the conclusion, that most of the workers
have an objective chronic sleep deficit. Despite a low number of test
SLEEP, Volume 34, Abstract Supplement, 2011
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