Exploring the Role of Sickness Absence Coordinators in Implementing Interventions to Reduce Sickness Absence in Public Sector Workplaces in Denmark.

PURPOSE: In 2019, an initiative to reduce sickness absence in public sector workplaces in Denmark was introduced. The initiative involved appointing a sickness absence coordinator (SA coordinator) to oversee the implementation of workplace-based sickness absence interventions. Since the role of the SA coordinator is a novel concept introduced as part of the initiative, this study investigates the responsibilities of SA coordinators and the challenges they experienced in fulfilling this role during the implementation process. METHODS: Semi-structured interviews with and observations of SA coordinators from four public sector workplaces were carried out. We collected the first four interviews and observations during the implementation process with follow-up interviews collected at the end of the process. The data were analyzed using thematic analysis. RESULTS: The SA coordinators all experienced challenges in terms of lack of commitment among the line managers to participate in the intervention. They experienced being seen as a burden rather than a helping hand, and felt that the line managers might have difficulty recognizing the value of the SA coordinators. Potential ways to improve the collaboration between the SA coordinators and the line managers include considering hiring the SA coordinator in-house and incorporation of intervention components into existing activities to accommodate the busyness of the line managers. CONCLUSIONS: To support the SA coordinators in carrying out their role and responsibilities, this study suggests that it is important to ensure commitment to the role, especially among the line managers in order to enhance good working relationships.

Associations between saliva alpha-amylase, heart rate variability, saliva cortisol and cognitive performance in individuals at ultra high-risk for psychosis.

BACKGROUND: Cognitive impairments are present in individuals at ultra-high risk (UHR) of psychosis and UHR individuals exhibit a hyperactive and dysfunctional HPA-axis. Increasing stress levels could potentially lead to cognitive impairments and no previous studies have examined the association between physiological stress biomarkers and cognition in UHR individuals. This study aims to examine the association between saliva alpha amylase (SAA), heart rate variability (HRV), saliva cortisol, and cognition in UHR individuals. METHOD: We included 72 UHR individuals, aged 18-40, fulfilling criteria of the comprehensive assessment of at-risk mental state (CAARMS). Cognitive tests indexed the 7 core domains as stated by Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS). Physiological stress levels were observed for one day: saliva was collected at awakening, 30 min and 60 min after awakening and at bedtime. HRV was measured during sleep and before awakening. We used generalized linear model and controlled for multiple testing using false discovery rate (FDR). RESULTS: Higher levels of SAA were significantly associated with lower cognitive performance in the domains of verbal and visual learning and memory, sustained attention, working memory and global neurocognition looking at unadjusted data. Controlling for FDR visual memory, sustained attention and global neurocognition remained significant associated with SAA. We discovered no associations between cortisol and cognition. CONCLUSION: Visual learning and memory, sustained attention and global neurocognition remained significantly associated with SAA. This finding supports our hypothesis that an association between abnormal stress biomarkers and impaired cognition might be present in UHR individuals.

A longitudinal study on physiological stress in individuals at ultra high-risk of psychosis.

INTRODUCTION: Individuals at ultra high-risk (UHR) of psychosis exhibit significantly higher stress levels than healthy controls (HC). This study investigates how physiological stress measures differ between HC and UHR individuals and how physiological stress is associated with attenuated psychotic symptoms and changes over time in UHR individuals. Additionally, it examines how the use of medication affects physiological levels of stress. METHOD: The study included 72 UHR individuals and 36 HC. UHR were included according to the comprehensive assessment of at-risk mental state (CAARMS); a total-CAARMS score measured the attenuated psychotic symptoms and was calculated from the four psychosis subscales. HC and UHR were examined at baseline, and 47 UHR individuals were followed up after six months. Physiological stress measures were salivary cortisol, alpha-amylase (SAA) and heart-rate variability (HRV). Saliva was collected at four-time points during the day. RESULTS: There was no significant difference regarding cortisol (awakening response) or SAA measures between HC and UHR individuals. The use of antipsychotics and antidepressants was associated with low HRV in UHR individuals. In an exploratory analysis of 19 UHR individuals, we found an association between the change in total-CAARMS (six months total-CAARMS minus baseline total CAARMS) and the change in HRV during sleep (six months HRV minus baseline HRV). CONCLUSION: Our findings indicate that the use of antipsychotics and antidepressants could be associated with lower HRV in UHR individuals. There might be potential to investigate how HRV develops during the course of illness in UHR individuals.

Do different job demands interact as predictors of long-term sickness absence? A register-based follow-up on 55 467 Danish workers.

OBJECTIVES: To assess interactions between combinations of quantitative demands, emotional demands, unclear and contradictory demands, and violence/threats of violence in the prospective association with risk of long-term sickness absence (LTSA). METHODS: We included 55 467 employees from the 2012, 2014 and 2016 waves of the Work Environment and Health in Denmark (WEHD) survey. We measured the four independent variables in the WEHD survey and assessed risk of LTSA in a national register during 12 months of follow-up. Using Cox proportional hazards models, adjusted for age, sex, educational attainment and job group, we estimated risk of LTSA and assessed deviation from additivity using relative excess risk due to interaction (RERI). RESULTS: For combinations of high emotional demands and high quantitative demands (HR 1.50; 95% CI 1.33 to 1.70; RERI 0.06; 95% CI -0.15 o 0.26) and high emotional demands and violence/threats of violence (HR 1.76; 95% CI 1.53 to 2.02; RERI 0.12; 95% CI -0.43 to 0.66) we found no indications of deviations from additive effects in predicting LTSA. For combinations of violence/threats of violence and high quantitative demands (HR 1.90; 95% CI 1.64 to 2.20; RERI 0.36; 95% CI 0.01 to 0.71) and unclear and contradictory demands and high quantitative demands (HR 1.46; 95% CI 1.31 to 1.62; RERI 0.23; 95% CI 0.04 to 0.42) the results indicated an excess risk of LTSA above additivity (ie, superadditivity). CONCLUSIONS: Participants reporting high quantitative demands combined with either violence/threats of violence or unclear and contradictory demands showed a higher risk of LTSA than expected, indicating superadditivity. Results have implications for preventing negative health effects related to adverse psychosocial working conditions.

Self-Reported Sleepiness after 2, 4, and 7 Consecutive Night Shifts and Recovery Days in Danish Police Officers.

BACKGROUND: Night shift work often implies shorter sleep duration and this can lead to sleepiness, which has been associated with an increased risk of accidents and injuries. The aim is to study how the number of consecutive night shifts affects self-reported sleepiness. PARTICIPANTS AND METHODS: The study was a quasi-experimental, within-subject crossover study with 73 police officers. Three work schedules of two, four, and seven consecutive night shifts followed by the same number of recovery days, i.e., days worked or days off, was performed by all participants. Sleepiness was self-reported using the Karolinska sleepiness scale (KSS) every fourth hour on the last night shift and the last recovery day in each sequence. RESULTS: We observed differences in the level of sleepiness between recovery days and night shift days but no differences in the pattern of sleepiness levels on night shift days in the different work schedules. The highest levels of KSS were observed before bedtime (at 07:00 after a night shift and 23:00 on a recovery day). CONCLUSION: The number of consecutive night shifts did not affect the self-reported levels of self-reported sleepiness among Danish police officers.

Heart rate variability during sleep after two, four and seven consecutive night shifts and recovery days: a cross-over intervention study.

OBJECTIVE: Recovery after shift work is an important part reducing the health problems related to shift work. Heart rate variability (HRV) is an indicator of the balance between sympathetic and parasympathetic activity in the autonomic nervous system and can be used as a measure of recovery after night shifts. The aim of the study is to investigate autonomic recovery during sleep in response to night work in a crossover intervention study. METHODS: Seventeen male police officers working in call centres in five different police district participated in the HRV measurements. The participants were exposed to three interventions: 2 + 2: two consecutive night shifts followed by two consecutive day recovery days; 4 + 4: four consecutive night shifts followed by four consecutive recovery days; 7 + 7: seven consecutive night shifts followed by seven consecutive recovery days. On the last day with night shift and the last recovery day in each intervention the participants underwent 24 h HRV recordings. We analysed HRV during sleep. The five 5-min intervals with the lowest heart rate during each sleep period were chosen for spectral analysis of the heart interbeat interval time series. The five 5-min intervals could occur at any time during sleep. RESULTS: There were overall differences in HRV during sleep between days with night shifts and recovery days, primarily in parasympathetic activity. There was no difference in the lowest heart rate obtained, but the timing was different for the three interventions. The lowest heart rate after night shifts occurred 112 (SD 79) min, 174 (SD 115) min and 135 (SD 94) min after sleep onset for the 2 + 2 night shift, the 4 + 4 night shift and the 7 + 7 night shift, respectively. CONCLUSION: Overall sleep-related autonomic recovery had higher parasympathetic modulation of cardiac rhythm on the 2 + 2 shift system compared to the 4 + 4 and 7 + 7 shift system.

The urinary 6-sulfatoxymelatonin level after three different work schedules with 2, 4 and 7 consecutive night shifts among Danish police officers.

Night shift work suppresses excretion of melatonin, but little is known about the needed time for recovery. We aimed to compare levels of 6-sulfatoxy melatonin after three different night shift schedules, including recovery days. In a quasi-experimental, within-subject crossover study, 73 male police officers in Denmark collected morning urine after the last recovery day in three different work schedules with two, four, and seven consecutive night shifts followed by a corresponding number of days for recovery. We found no significant differences for 6-sulphatoxymelatonin concentrations in morning urine between the three different work schedules indicating similar recovery of melatonin suppression in the studied work schedules.

Leadership Quality and Risk of Long-term Sickness Absence Among 53,157 Employees of the Danish Workforce.

OBJECTIVE: To examine whether low leadership quality predicts long-term sickness absence (LTSA) in Denmark. METHODS: Using Cox models, we estimated the association between exposure to low leadership quality and onset of register based LTSA (more than or equal to 6 weeks) during 12-months follow-up among 53,157 employees without previous LTSA. RESULTS: During 51,155 person-years, we identified 2270 cases of LTSA. Low leadership quality predicted LTSA with a dose-respone pattern after adjustment for confounders. The hazard ratio (HR) of LTSA in the lowest compared with the highest quartile of leadership quality was 1.61 (95% CI: 1.43 to 1.82). Further, change from high to low leadership quality over time predicted risk of LTSA (HR = 1.42, 95% CI: 1.02 to 1.97) compared with persistent high leadership quality. CONCLUSIONS: Exposure to low leadership quality is a risk factor of LTSA in the Danish workforce.

The effects of the number of consecutive night shifts on sleep duration and quality.

Objectives The organization of night shift work affects sleep duration and quality. The aim of this study was to investigate the effects of the number of consecutive night shifts on sleep duration and quality among police officers with night shift work as part of their normal schedule. Methods This quasi-experimental, within-subject crossover study included 73 police officers. All participants performed three work schedules: two, four and seven consecutive night shifts followed by the same number of recovery days, ie, day work or days off (2+2, 4+4, and 7+7). Sleep assessed through sleep diaries and actigraphy after all night shifts and recovery days (totaling 26 days) was compared by use of repeated measures analysis. Results Participants experienced shorter sleep duration (with and without naps), more premature awakening, less difficulty falling asleep, and more non-refreshing sleep after night shifts compared with recovery days. Sleep duration and quality did not change with increasing number of consecutive night shifts. Sleep was shorter and of poorer quality after the last night shift in the 2+2 and 4+4 work schedule compared with the second and fourth night shift, respectively, in the 7+7 schedule. Conclusion Sleep duration was reduced after night shift work and did not increase with more consecutive night shifts, which leads to accumulated sleep debt. Sleep duration was shortest and sleep quality was poorest after the last night shift in a series of night shifts.

Comparison of exhaustion symptoms in patients with stress-related and other psychiatric and somatic diagnoses.

BACKGROUND: Several rating scales assessing stress-related symptoms of exhaustion have emerged in recent years. However, more knowledge is needed about the performance of these rating scales in patients with stress-related disorders as well as in other patient groups. With the recently developed Karolinska Exhaustion Disorder Scale (KEDS), we compared symptoms of exhaustion in different patient groups that were sorted according to diagnosis. METHODS: Patients were sampled consecutively from departments of occupational medicine (DOM) at three Danish hospitals. The total study group comprised 698 care-seeking patients (487 women). Patients with stress-related diagnoses (n = 217; the International Classification of Diseases [ICD]-10 code F43: reaction to severe stress and adjustment disorder) were compared to a diverse group of patients with a range of somatic diagnoses (n = 338) and to patients with other psychiatric diagnoses (n = 143), including subgroups with major depression disorder (n = 34; F32 and F33) and problems related to employment and unemployment (n = 99; Z56). The data were analysed using linear mixed models with the SPSS statistical program. RESULTS: The mean KEDS sum score in patients with stress-related diagnoses (29.3; SD = 8.0) was significantly higher than in patients with other psychiatric diagnoses (25.9; SD = 9.5) and in patients with somatic diagnoses (17.6; SD = 10.8). The subgroup with a major depression disorder had high mean KEDS sum scores (31.4, SD = 8.1), similar to patients with stress-related diagnoses, while the mean KEDS sum score in patients with problems related to employment and unemployment (Z56) was 23.5 (SD = 9.0). Young and old patients scored similarly on KEDS, but in patients with somatic diagnoses, female patients scored significantly higher than male patients. CONCLUSION: The symptoms of exhaustion measured with KEDS were higher in patients with stress-related diagnoses and major depression disorder than in patients with somatic diagnoses. The intermediate level of the symptoms of exhaustion that were associated with problems related to employment and unemployment, (Z56) compared to the lower level of the symptoms with somatic diagnoses, suggests that KEDS might be useful in detecting mild, prodromal states of exhaustion. This needs further investigation.

Perceived stress and sickness absence: a prospective study of 17,795 employees in Denmark.

OBJECTIVES: The aims were to examine (1) the prospective association between perceived stress and sickness absence, and if this association (2) differed by sex, and (3) was stronger when only long-term sickness absence (≥ 31 days) instead of all-length sickness absence (≥ 1 day) was included. Moreover, different cut-points for the length of the sickness absence periods were applied. METHODS: We followed respondents (10,634 women and 7161 men) from the 'Work Environment and Health in Denmark' 2014-survey for up to 18 months in the 'Register of Work Absences' from Statistics Denmark. Perceived stress was measured by a single question: "In the last 2 weeks, how often have you felt stressed?" We used Cox-regression with repeated events, adjusted for age, sector, education, and previous sickness absence. RESULTS: The hazard ratio (HR) for all-length sickness absence (≥ 1 day) for "Often/Always" stress compared to "Seldom/Never" stress was statistically significant among both men (HR = 1.25 [1.13-1.38]) and women (HR = 1.43 [1.34-1.51]). The HR was statistically significant for women (HR = 2.26 [1.89-2.70]), but not for men (HR = 1.22 [0.86-1.73]), when the analyses were restricted to long-term sickness absence (≥ 31 days). The sex-difference was statistically significant. Additional analyses with cut-points at ≥ 2, ≥ 4, ≥ 6, ≥ 8, ≥ 11, ≥ 15, ≥ 20, and ≥ 25 sickness absence days showed that among women, the HR increased gradually with increasing lengths of the sickness absence periods. CONCLUSIONS: The prospective association of perceived stress with risk of sickness absence was stronger among women than men. Among women, perceived stress was more strongly associated with long-term sickness absence than with all-length sickness absence.

The association between multisite musculoskeletal pain and cardiac autonomic modulation during work, leisure and sleep - a cross-sectional study.

BACKGROUND: The prevention and rehabilitation of multisite musculoskeletal pain would benefit from studies aiming to understand its underlying mechanism. Autonomic imbalance is a suggested mechanism for multisite pain, but hardly been studied during normal daily living. Therefore, the aim of the study is to investigate the association between multisite musculoskeletal pain and cardiac autonomic modulation during work, leisure and sleep. METHODS: This study is based on data from the "Danish Physical activity cohort with objective measurements" among 568 blue-collar workers. Pain intensity scales were dichotomized according to the median of each scale, and the number of pain sites was calculated. No site was regarded as the pain-free, one site was considered as single-site musculoskeletal pain and pain in two or more sites was regarded as multisite musculoskeletal pain. Heart rate variability (HRV) was measured by an electrocardiogram system (ActiHeart) and physical activity using accelerometers (Actigraph). Crude and adjusted linear mixed models were applied to investigate the association between groups and cardiac autonomic regulation during work, leisure and sleep. RESULTS: There was no significant difference between groups and no significant interaction between groups and domains in the crude or adjusted models for any HRV index. Significant differences between domains were found in the crude and adjusted model for all indices, except SDNN; sleep time showed higher values than leisure and work time, except for LF and LF/HF, which were higher during work. CONCLUSION: This cross-sectional study showed that multisite musculoskeletal pain is not associated with imbalanced cardiac autonomic regulation during work, leisure and sleep time.

Content and quality of workplace guidelines developed to prevent mental health problems: results from a systematic review.

Objectives A wide range of guidelines have been developed to prevent work-related mental health problems (MHP), but little is known about the quality of such guidelines. We systematically reviewed the content and quality of workplace guidelines aiming to prevent, detect, and/or manage work-related MHP. Methods We conducted systematic online and database searches (MEDLINE; Web of Science; PsychNET; occupational safety and health databases) to identify guidelines. Eligibility criteria included guidelines recommending primary, secondary, or tertiary preventive interventions to be implemented at the workplace by employers, employees or organizational staff. A minimum of minimum three independent reviewers assessed the quality of guidelines using the Guidelines for Research and Evaluation (AGREE II). Guidelines rated ≥65% with regards to domain I, II, and III were considered to be of good developmental quality. Results Seventeen guidelines were quality assessed. Guidelines mainly targeted employers: eight guidelines recommended primary preventive interventions (eg, reduction of psychosocial hazards by risk management procedures), three recommended tertiary (eg, stay at work or return to work procedures for management), and six recommended a combination of primary, secondary and tertiary interventions (eg, facilitate return to work by increasing mental health literacy of all staff and coordination of sick-listed employees). Four guidelines had developed recommendations of good quality, but the evidence of two guidelines was outdated and studies documenting the effect of implementation were not yet available. Conclusions Few guidelines have been developed with sufficient rigor to help employers prevent or manage work-related MHP and evidence of their effectiveness remains scarce.

Opinion and Special Articles: Stress when performing the first lumbar puncture may compromise patient safety.

OBJECTIVE: To quantify physician stress levels when performing lumbar puncture (LP) and explore operator stress effect on patient outcomes. METHODS: This was a cross-sectional, multicenter study. Novices, intermediates, and experts in performing LP were recruited from 4 departments of neurology and emergency medicine. Stress was measured before and during performance of the LP using cognitive appraisal (CA), State-Trait Anxiety Inventory-Short (STAI-S) questionnaire, and the heart rate variability measure low frequency/high frequency index (LF/HF ratio). Patient-related outcomes were pain, confidence in the operator, and postdural puncture headache (PDPH). RESULTS: Forty-six physicians were included in the study: 22 novices, 12 intermediates, and 12 experts. Novices had the highest stress level and experts the lowest measured by cognitive appraisal and STAI-S before and during LP performance (p < 0.001 for all comparisons). Novices had the highest sympathetic tonus indicated by the highest LF/HF ratio before (p = 0.004) and during (p = 0.056) LP performance. Physician stress level was not significantly related to patients' pain. However, there was a significant relationship between STAI-S during the procedure and patient confidence in the operator (regression coefficient = -0.034, p = 0.008). High physician heart rate during the procedure significantly increased the odds of PDPH (odds ratio = 1.17, p = 0.036). CONCLUSION: Novice stress levels were high before and during performance of LP. Stress was significantly related to patient confidence in the operator and risk of PDPH. Simulation-based training should be considered to reduce novice residents' stress levels and increase patient safety.

Different autonomic responses to occupational and leisure time physical activities among blue-collar workers.

PURPOSE: The differential effect of occupational and leisure time physical activity on cardiovascular health is termed the physical activity health paradox. Cardiac autonomic modulation could bring insights about the underlying mechanism behind this differential effect. The aim was to compare heart rate variability (HRV) during different activities (sitting, standing and moving) at work and leisure among blue-collar workers. METHODS: One hundred thirty-eight workers from the NOMAD cohort were included. Data from physical activity and HRV were obtained for 3-4 days using tri-axial accelerometers (Actigraph GT3X+) and a heart rate monitor (Actiheart). HRV indices were determined during sitting, standing and moving both at work and leisure. Linear mixed-models with two fixed factors (activities and domains) were applied to investigate differences in HRV indices adjusting for individual and occupational factors. RESULTS: The results showed significant effects of domain (p < 0.01), physical activity type (p < 0.01) and interaction between domain and activity type (p < 0.01) on HRV indices. Mean heart rate (IBI) and parasympathetic measures of HRV (RMSSD and HF) were lower for sitting (p < 0.01) and higher for moving (p < 0.01) during work compared with leisure, while no difference between domains was found for standing (p > 0.05). Sympathovagal balance (LF/HF) was higher during work for sitting and moving (p < 0.01), but showed no difference for standing (p = 0.62). CONCLUSIONS: Differences in cardiac autonomic modulation between work and leisure were found, indicating sympathetic predominance during work and parasympathetic predominance during leisure for sitting. Autonomic responses can be part of the mechanism that explains the differential effect of occupational and leisure time physical activity on health.

Noise-Induced Hearing Loss - A Preventable Disease? Results of a 10-Year Longitudinal Study of Workers Exposed to Occupational Noise.

AIMS: To survey current, Danish industrial noise levels and the use of hearing protection devices (HPD) over a 10-year period and to characterise the association between occupational noise and hearing threshold shift in the same period. Furthermore, the risk of hearing loss among the baseline and the follow-up populations according to first year of occupational noise exposure is evaluated. MATERIALS AND METHODS: In 2001-2003, we conducted a baseline survey of noise- and hearing-related disorders in 11 industries with suspected high noise levels. In 2009-2010, we were able to follow up on 271 out of the 554 baseline workers (49%). Mean noise levels per industry and self-reported HPD use are described at baseline and follow-up. The association between cumulative occupational noise exposure and hearing threshold shift over the 10-year period was assessed using linear regression, and the risk of hearing loss according to year of first occupational noise exposure was evaluated with logistic regression. RESULTS: Over the 10-year period, mean noise levels declined from 83.9 dB(A) to 82.8 dB(A), and for workers exposed >85 dB(A), the use of HPD increased from 70.1 to 76.1%. We found a weak, statistically insignificant, inverse association between higher ambient cumulative noise exposure and poorer hearing (-0.10 dB hearing threshold shift per dB-year (95% confidence interval (CI): -0.36; 0.16)). The risk of hearing loss seemed to increase with earlier first year of noise exposure, but odds ratios were only statistically significant among baseline participants with first exposure before the 1980s (odds ratio: 1.90, 95% CI: 1.11; 3.22). CONCLUSIONS: We observed declining industrial noise levels, increased use of HPD and no significant impact on hearing thresholds from current ambient industrial noise levels, which indicated a successful implementation of Danish hearing conservation programs.

It is not all bad for the grey city - A crossover study on physiological and psychological restoration in a forest and an urban environment.

Today, urbanization presents a challenge to urban planning with regard to creating healthy living environments. The aim of this research is to gain further knowledge of the restorativeness of a best case urban and natural environment: that is a historic down town urban environment and forest environment located in an arboretum. The study has a cross-over design where 51 (N) female university students are exposed to the two environments through both seated viewing and walking. A mixed method approach is used with both physiological measurements of blood pressure (BP) and heart rate variability (HRV) and psychological measurements of mood change and perceived restorativeness. The HRV results show no significant differences between the two environments, and both environments are found to be more physiologically restorative than being at the office or on the minibus. The results of the psychological measures indicate that the forest walk has a positive effect on mood, while the walk in the urban environment has no effect. The forest environment is also rated more highly with regard to perceived restorativeness than the urban environment. The results support the current research that shows natural environments as more restorative than urban environments. The study also adds to the ongoing debate on healthy urban planning by indicating that architectural and historical qualities may be associated with the physiological well-being of citizens.

Occupational noise exposure, psychosocial working conditions and the risk of tinnitus.

PURPOSE: The purpose of this study was to evaluate the influence of occupational noise (current and cumulative doses) and psychosocial work factors (psychological demands and decision latitude) on tinnitus occurrence among workers, using objective and non-self-reported exposure measures to prevent reporting bias. METHODS: In a cross-sectional study, we analyzed data from a Danish survey from 2009 to 2010 that included 534 workers from children day care units and 10 manufacturing trades. Associations between risk factors (current noise exposure, cumulative noise exposure and psychosocial working conditions) and tinnitus were analyzed with logistic regression. RESULTS: We found no statistically significant associations between either current [OR 0.95 (95% CI 0.89; 1.01)] or cumulative [OR 0.93 (95% CI 0.81; 1.06)] occupational noise exposure and tinnitus. Likewise, results for psychosocial working conditions showed no statistically significant association between work place decision latitude [OR 1.06 (95% CI 0.94; 1.13)] or psychological demands [OR 1.07 (95% CI 0.90; 1.26)] and tinnitus. CONCLUSIONS: Our results suggest that current Danish occupational noise levels (in combination with relevant noise protection) are not associated with tinnitus. Also, results indicated that the psychosocial working conditions we observed in this cohort of mainly industrial workers were not associated with tinnitus. Therefore, psychosocial working conditions comparable to those observed in this study are probably not relevant to take into account in the evaluation of workers presenting with tinnitus.

Effect of an aerobic exercise intervention on cardiac autonomic regulation: A worksite RCT among cleaners.

OBJECTIVE: The aim of this randomized controlled trial (RCT) was to determine whether aerobic exercise during work hours affects cardiac autonomic regulation in cleaners characterized by high levels of occupational physical activity and poor cardiorespiratory fitness. METHOD: Eligible cleaners (n=116) were randomized to an aerobic exercise group (n=59) or a reference group (n=57) with lectures. The intervention group received two 30-min sessions per week of supervised aerobic exercise over 4months. Diurnal measurements of heart rate variability (HRV) and physical activity (accelerometry) were obtained at baseline and at 4-month follow-up. Time and frequency domain indices of HRV were derived during work, leisure time and sleep to evaluate cardiac autonomic regulation. Linear mixed models were used to determine the effect of the intervention on HRV indices, with adjustment for age, gender and daily use of antihypertensive and/or heart medication. RESULTS: Compared with the reference group, the exercise group increased all HRV indices apart from a reduction in LF/HF ratio from baseline to follow-up both during work (p<0.05) and leisure (p<0.05). In contrast, during sleep, the HRV indices tended to decrease in the exercise group compared with the reference group from baseline to follow-up, being significant for the HF spectral component (p=0.03). CONCLUSION: Among cleaners, a worksite aerobic exercise intervention improved cardiac autonomic regulation during work and leisure, but not during sleep. The health effect of this contrasting change in autonomic regulation needs further investigation.

Changes in the diurnal rhythms of cortisol, melatonin, and testosterone after 2, 4, and 7 consecutive night shifts in male police officers.

Night work is associated with a large range of acute health problems and possibly also health consequences in the long run. Yet, only very few field studies specifically investigate the effects of consecutive night shift on key physiological regulatory systems. In this field study, we investigated the effects of consecutive night shifts on three hormones, melatonin, cortisol, and testosterone, among police officers at work. More specifically, the aim was to investigate how the diurnal rhythms of melatonin, cortisol, and testosterone responded to two, four, and seven consecutive night shifts and a corresponding number of days for recovery. The study was part of the "In the Middle of the Night" project and included 73 male police officers from five different police districts. The participants were exposed to three intervention conditions: "2+2": two consecutive night shifts followed by two consecutive day recovery days; "4+4": four consecutive night shifts followed by four consecutive recovery days; "7+7": seven consecutive night shifts followed by seven consecutive recovery days. On the last day with night shift and the last recovery day in each intervention, the participants collected saliva samples every 4th hour when awake. The diurnal rhythms of melatonin, cortisol, and testosterone were all affected differently by an increasing number of consecutive night shifts: the amplitude of the melatonin rhythm was suppressed by 4.9% per day (95% CI 1.4-8.2% per day; p = 0.006). The diurnal rhythm of cortisol phase was delayed with an increasing number of night shifts by 33 min/day (95% CI 18-48 min per day; p ≤ 0.001), but did not show any changes in amplitude. For the diurnal rhythm of testosterone, there was no effect of the number of consecutive night shifts and the diurnal rhythm completely followed the sleep/wake cycle. We found that there were no differences in the rhythms of melatonin, cortisol, and testosterone after 2, 4, and 7 recovery days, respectively. In conclusion, we found signs of desynchronization in terms of suppressed amplitude of melatonin and phase delay of salivary cortisol as a consequence of the increasing number of consecutive night shifts among police officers at work. Lack of synchronization has been suggested as a possible mechanism linking night work to disease, but this remains to be determined.