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- Bjorvatn, Bjørn, et al.
(author)
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Shift workers are at increased risk of severe COVID-19 compared with day workers : Results from the international COVID sleep study (ICOSS) of 7141 workers.
- 2023
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In: Chronobiology International. - : Taylor & Francis. - 0742-0528 .- 1525-6073. ; 40:2, s. 114-122
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Journal article (peer-reviewed)abstract
- The present study had two main aims. First, to investigate whether shift/night workers had a higher prevalence and severity of COVID-19 compared with day workers. Second, to investigate whether people regularly working in face-to-face settings during the pandemic exhibited a higher prevalence and severity of COVID-19 compared with those having no need to be in close contact with others at work. Data consisted of 7141 workers from 15 countries and four continents who participated in the International COVID Sleep Study-II (ICOSS-II) between May and December 2021. The associations between work status and a positive COVID-19 test and several indications of disease severity were tested with chi-square tests and logistic regressions adjusted for relevant confounders. In addition, statistical analyses were conducted for the associations between face-to-face work and COVID-19 status. Results showed that shift/night work was not associated with an increased risk of COVID-19 compared to day work. Still, shift/night workers reported higher odds for moderate to life-threatening COVID-19 (adjusted odds ratio (aOR) = 2.71, 95%-confidence interval = 1.23-5.95) and need for hospital care (aOR = 5.66, 1.89-16.95). Face-to-face work was associated with an increased risk of COVID-19 (aOR = 1.55, 1.12-2.14) but not with higher disease severity. In conclusion, shift/night work was not associated with an increased risk of COVID-19, but when infected, shift/night workers reported more severe disease. Impaired sleep and circadian disruption commonly seen among shift/night workers may be mediating factors. Working face-to-face increased the risk of COVID-19, likely due to increased exposure to the virus. However, face-to-face work was not associated with increased disease severity.
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| 2. |
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| 3. |
- Martins, Andressa J., et al.
(author)
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The effect of urbanization on sleep, sleep/wake routine, and metabolic health of residents in the Amazon region of Brazil
- 2020
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In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 37:9-10, s. 1335-1343
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Journal article (peer-reviewed)abstract
- Studying communities with different levels of urbanization may further the understanding of risk factors underlying metabolic diseases. The present study is unique by comprising detailed assessment of sleep and activity, biological rhythms, and metabolic factors of men from the same geographical location and place of birth that reside in different, rural vs. town, stages of urbanization. Sleep patterns, activity, and metabolic indicators in two groups (rural, n = 22 and town/urban, n = 20) of men residing in an Amazonian community (Xapuri, Acre, Brazil) were compared. Sociodemographic, anthropometric, and metabolic variables - fasting glucose, insulin resistance, triglycerides, total HDL cholesterol, LDL cholesterol, and VLDL cholesterol - were assessed. Sleep patterns, light exposure, and physical activity levels were additionally assessed by actigraphy, plus daily activities were recorded in diaries for 10 days. Town/urban dwellers were found to have significantly higher body weight, fasting glucose, insulin levels, and insulin resistance than rural dwellers, whereas triglycerides levels were similar. Town/Urban dwellers had shorter sleep duration (p< .01) and later sleep onset and offset times (p= .01). Our findings show an association between stage of urbanization and presence of risk factors for metabolic disorders, such as overweight, insulin resistance, increased glucose levels, short sleep duration, and less natural light exposure during work times.
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| 5. |
- Sallinen, Mikael, et al.
(author)
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Self-reported reasons for on-duty sleepiness among commercial airline pilots
- 2021
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In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 38:9, s. 1308-1318
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Journal article (peer-reviewed)abstract
- Experimental and epidemiological research has shown that human sleepiness is determined especially by the circadian and homeostatic processes. The present field study examined which work-related factors airline pilots perceive as causing on-duty sleepiness during short-haul and long-haul flights. In addition, the association between the perceived reasons for sleepiness and actual sleepiness levels was examined, as well as the association between reporting inadequate sleep causing sleepiness and actual sleep-wake history. The study sample consisted of 29 long-haul (LH) pilots, 28 short-haul (SH) pilots, and 29 mixed fleet pilots (flying both SH and LH flights), each of whom participated in a 2-month field measurement period, yielding a total of 765 SH and 494 LH flight duty periods (FDPs) for analyses (FDP, a period between the start of a duty and the end of the last flight of that duty). The self-reports of sleepiness inducers were collected at the end of each FDP by an electronic select menu. On-duty sleepiness was rated at each flight phase by the Karolinska Sleepiness Scale (KSS). The sleep-wake data was collected by a diary and actigraph. The results showed that “FDP timing” and “inadequate sleep” were the most frequently reported reasons for on-duty sleepiness out of the seven options provided, regardless of FDP type (SH, LH). Reporting these reasons significantly increased the odds of increased on-duty sleepiness (KSS ≥ 7), except for reporting “inadequate sleep” during LH FDPs. Reporting “inadequate sleep” was also associated with increased odds of a reduced sleep-wake ratio (total sleep time/amount of wakefulness ≤ 0.33). Both “FDP timing” and “inadequate sleep” were most frequently reported during early morning and night FDPs, whereas the other options showed no such phenomenon. The present study suggests that airline pilots’ perceptions of work-related factors that make them sleepy at work are in line with the previous experimental and epidemiological studies of sleepiness regulation.
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| 6. |
- Silva-Costa, Aline, et al.
(author)
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Lifetime night work exposure and the risk of type 2 diabetes : results from the longitudinal study of adult health (ELSA-Brasil)
- 2020
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In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 37:9-10, s. 1344-1347
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Journal article (peer-reviewed)abstract
- The aim of this research project was to test the effects of lifetime night work exposure on type 2 diabetes (T2DM) risk. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a prospective cohort study of chronic conditions, such as diabetes and cardiovascular disease. The participants (N = 15105) were recruited (2008–2010) at five public universities and one research institute in six cities in Brazil. Participants from the first wave (2008–2010) were followed up for a mean of 3.8 years. Current analyses comprise 4671 women and 3965 men. Hazard ratios (HR) were estimated using Cox regression models. Crude T2DM incidence rates were 2.26 and 1.44 per 100 person-years, respectively, for women and men who reported ≥ 10 years’ working nights. In women, ≥ 10 years of night work was associated with a higher risk of T2DM (HR 1.46 [95% CI: 1.03; 2.08]), after adjusting for age, education, work hours, and BMI. The additional adjustment for physical activity attenuated the association (HR 1.36 [95% CI: 0.94; 1.96]). In men, the results were not statistically significant (HR = 0.65 [95% CI: 0.40; 1.07]). The findings indicate the effects of lifetime night work on T2DM incidence seem to be greater among women than men.
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| 7. |
- Tucker, Philip, et al.
(author)
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Can psychosocial working conditions help to explain the impact of shiftwork on health in male- and female-dominated occupations? : A prospective cohort study
- 2020
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In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 37:9-10, s. 1348-1356
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Journal article (peer-reviewed)abstract
- Occupational factors are sometimes invoked to explain gender differences in the associations between shiftwork and health. We examined prospective associations between shiftwork and health, and between shiftwork and sick leave, separately for workers in female-dominated (FD) and male-dominated (MD) occupations; and whether the associations remained after controlling for psychosocial working conditions. Data from six waves of the Swedish Longitudinal Occupational Survey of Health were used to examine prospective associations with a four-year time lag between work schedule (daywork versus shiftwork involving nightwork; and daywork versus shiftwork not involving nightwork) and self-reports of depressive symptoms; incidents of short- and long-term sick leave; self-rated health; and sleep disturbance. Dynamic panel models with fixed effects were applied, using structural equation modeling. The analyses included adjustments for personal circumstances and employment conditions; and additional adjustments for psychosocial working conditions (psychological and emotional job demands; job control; worktime control; social support at work; persecution at work; and threats or violence at work). Within FD occupations, shiftwork that included night work (as compared to daytime work) predicted higher incidence of short-term sick leave (<1 week); within MD occupations, shiftwork that included nightwork predicted greater symptoms of mild depression. Despite notable differences in psychosocial working conditions between dayworkers and shiftworkers, both associations remained significant after adjustments. Thus, it was not confirmed that the associations between shiftwork and health reflected poorer working conditions of shiftworkers in either FD or MD occupations, although the possibility remains that the associations were due to other unmeasured aspects of the working environment.
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| 8. |
- Urbanová, Lucie, et al.
(author)
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The impact of sleep education, light intervention and relaxation on sleep and mood in the elderly
- 2024
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In: Chronobiology International. - : Taylor & Francis. - 0742-0528 .- 1525-6073. ; 41:4, s. 567-576
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Journal article (peer-reviewed)abstract
- Sleep and light education (SLE) combined with relaxation is a potential method of addressing sleep and affective problems in older people. 47 participants took part in a four-week sleep education program. SLE was conducted once a week for 60–90 minutes. Participants were instructed on sleep and light hygiene, sleep processes, and practiced relaxation techniques. Participants were wearing actigraphs for 6 weeks, completed daily sleep diaries, and wore blue light-blocking glasses 120 minutes before bedtime. Measures included scores of the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISS), Beck Depression Inventory-II (BDI-II), State-Trait Anxiety Inventory (STAI) and actigraphy measurements of sleep latency, sleep efficiency, and sleep fragmentation. Sleep quality increased after SLE based on the subjective assessment and in the objective measurement with actigraphy. PSQI scores were statistically reduced indicating better sleep. Scores after the intervention significantly decreased in ESS and ISS. Sleep latency significantly decreased, whereas sleep efficiency and fragmentation index (%), did not improve. Mood significantly improved after SLE, with lower scores on the BDI-II and STAI. SLE combined with relaxation proved to be an effective method to reduce sleep problems and the incidence of depressive and anxiety symptoms.
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| 9. |
- Vieira, R. P. O., et al.
(author)
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High social jetlag is correlated with nocturnal inhibition of melatonin production among night workers
- 2021
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In: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 38:8, s. 1170-1176
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Journal article (peer-reviewed)abstract
- Night work can lead to social jetlag (SJL), which can be briefly defined as the difference between social and biological time. In this sense, SJL has been viewed as a proxy for circadian misalignment. Studies have suggested that SJL may modify physiological processes, such as blood pressure, glucose metabolism, cortisol, and melatonin production. Therefore, we aimed to verify the correlation between SJL and nocturnal inhibition of melatonin production estimated by the concentration of its urinary metabolite (6-sulfatoximelatonin). The study included day workers (n = 9) and night workers (n = 13) from a public maternity hospital in the city of Sao Paulo. A questionnaire was used to obtain sociodemographic data, life habits, working conditions, and the Munich Chronotype Questionnaire (MCTQ(shift)) was used to assess chronotype. Urine was collected on workdays and days off to estimate the concentration of 6-sulfatoximelatonin (aMT6s), quantified by the ELISA method. We found SJL 13 times higher for night workers (10.6 h) than day workers (0.8 h). The excretion of aMT6s in night workers was statistically different on workdays as opposed to days off, with the lowest excretion on workdays, as expected. SJL was correlated with the aMT6s's delta between the night off and night on among night workers, indicating that the higher is the SJL, the lower is the melatonin production. As expected, social jetlag was higher among night workers, compared to day workers. Moreover, our findings showed that melatonin concentration is directly correlated with SJL.
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