Work-related psychosocial factors and inflammatory markers: A systematic review and meta-analysis.

OBJECTIVE: We conducted a systematic review and meta-analysis to evaluate the prospective effect of adverse work-related psychosocial factors on increases in inflammatory markers. METHODS: A systematic literature search was conducted in PubMed, Embase, PsycINFO, PsycARTICLES, and the Japan Medical Abstracts Society database. Studies were eligible for inclusion if they examined associations between work-related psychosocial factors and inflammatory markers (interleukin-6, tumor necrosis factor-alpha, and C-reactive protein), used longitudinal or prospective cohort designs, were conducted among workers, were original articles written in English or Japanese, and were published up to 2017 for the first search, October 2020 for the second, and November 2022 for the third. A meta-analysis was conducted using a random-effects model to assess the pooled effect size for the associations. A meta-regression analysis was used to estimate the association between length of follow-up and effect size. The ROBINS-I tool was used to assess risk of bias. RESULTS: Of the 11,121 studies identified in the first search, 29,135 studies from the second, and 9448 studies from the third, eleven were eligible for this review and meta-analysis. The pooled coefficient between adverse work-related psychosocial factors and inflammatory markers was significant and positive (ß = 0.014, 95% confidence interval: 0.005-0.023). However, a clear association was only observed for interleukin-6, and all the studies included had serious risks of bias. Meta-regression showed the effect size decreased depending on the follow-up period. CONCLUSION: This study revealed a weak positive association between adverse work-related psychosocial factors and increases in inflammatory markers. TRIAL REGISTRATION: PROSPERO CRD42018081553 (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=81553).

Associations among workplace environment, self-regulation, and domain-specific physical activities among white-collar workers: a multilevel longitudinal study.

BACKGROUND: Psychological and environmental determinants have been discussed for promoting physical activity among workers. However, few studies have investigated effects of both workplace environment and psychological determinants on physical activity. It is also unknown which domains of physical activities are promoted by these determinants. This study aimed to investigate main and interaction effects of workplace environment and individual self-regulation for physical activity on domain-specific physical activities among white-collar workers. METHODS: A multi-site longitudinal study was conducted at baseline and about 5-month follow-up. A total of 49 worksites and employees within the worksites were recruited. Inclusion criteria for the worksites (a) were located in the Kanto area, Japan and (b) employed two or more employees. Employee inclusion criteria were (a) employed by the worksites, (b) aged 18 years or older, and (c) white-collar workers. For outcomes, three domain-specific physical activities (occupational, transport-related, and leisure-time) at baseline and follow-up were measured. For independent variables, self-regulation for physical activity, workplace environments (parking/bike, signs/bulletin boards/advertisements, stairs/elevators, physical activity/fitness facilities, work rules, written policies, and health promotion programs), and covariates at baseline were measured. Hierarchical Linear Modeling was conducted to investigate multilevel associations. RESULTS: Of the recruited worksites, 23 worksites and 562 employees, and 22 worksites and 459 employees completed the baseline and the follow-up surveys. As results of Hierarchical Linear Modeling, stairs/elevator (γ=3.80 [SE=1.80], p<0.05), physical activity/fitness facilities (γ=4.98 [SE=1.09], p<0.01), and written policies (γ=2.10 [SE=1.02], p<0.05) were significantly and positively associated with occupational physical activity. Self-regulation for physical activity was associated significantly with leisure-time physical activity (γ=0.09 [SE=0.04], p<0.05) but insignificantly with occupational and transport-related physical activity (γ=0.11 [SE=0.16] and γ=-0.00 [SE=0.06]). Significant interaction effects of workplace environments (physical activity/fitness facilities, work rules, and written policies) and self-regulation were observed on transport-related and leisure-time physical activity. CONCLUSIONS: Workplace environments such as physical activity/fitness facilities, written policies, work rules, and signs for stair use at stairs and elevators; self-regulation for physical activity; and their interactions may be effective to promote three domain-specific physical activities. This study has practical implications for designing multi-component interventions that include both environmental and psychological approaches to increase effect sizes to promote overall physical activity.

Is self-rated health associated with blood immune markers in healthy individuals?

BACKGROUND: Although self-rated health (SRH) has been established as a robust predictor of morbidity and mortality, the immunological mechanisms underpinning this relationship are poorly understood. PURPOSE: This study examined the association of SRH with humoral and cellular immune markers in healthy individuals who reported no physical illnesses. METHOD: A total of 116 healthy Japanese white-collar employees (79 women and 37 men) at a pharmaceutical company, aged 23-62 (mean 32) years, underwent a blood draw for the measurement of circulating immune (T, B, and natural killer) cells, inflammatory cytokines (interleukin-6 and tumor necrosis factor-alpha), and plasma immunoglobulin G (IgG) and completed a health survey including SRH. The question regarding SRH ranged from "very good" (coded 1) to "very poor" (coded 5). Hierarchical multiple regression analysis was carried out to calculate the relationship between SRH and immune markers. RESULTS: In this sample, poor SRH was positively correlated with B (CD19(+)) cell numbers (beta = 0.260, p < 0.05) and IgG levels (beta = 0.335, p < 0.01) even after adjusting for depressive symptoms, age, education, marital status, smoking, alcohol consumption, physical activity, body mass index, sex, and sex x SRH interaction. The interaction between SRH and sex on the immune markers was not significant. CONCLUSION: Although the connection between SRH and immune markers was not strong in this context, the results suggest that poor SRH may be associated with reduced humoral immune system capacity to respond to new/latent challenges. The results provide some support for the immunological basis of SRH in healthier individuals.

Indoor exposure to natural bright light prevents afternoon sleepiness.

STUDY OBJECTIVES: The present study examined the effects of indoor exposure to natural bright light on afternoon sleepiness. DESIGN: Participants took part in 3 experimental conditions: (1) a natural bright light condition in which they carried out performance and arousal tests sitting near a window (3260.0 +/- 1812.43 lux) from 12:40 PM to 1:10 PM, (2) a nap condition in which they were provided a nap opportunity for 20 minutes from 12:45 PM, and (3) a control condition in which they performed the tests in less than 100 lux surroundings from 12:40 PM to 1:10 PM. Before and after each treatment, the same series of tests were administered. SETTING: A temperature- and light-controlled sleep laboratory. PARTICIPANTS: Sixteen healthy female paid volunteers aged 33 to 43 (38.1 +/- 2.68) years. INTERVENTIONS: Indoor natural bright light and a short nap. MEASUREMENTS AND RESULTS: Arousal levels were measured by the Psychomotor Vigilance Task, Alpha Attenuation Test, Karolinska Drowsiness Test, and Karolinska Sleepiness Scale. The tests were repeated every 30 minutes from 11:00 AM to 4:10 PM. Ambient light intensity was maintained at less than 100 lux, except during natural bright light exposure. Short-term exposure to natural bright light significantly improved afternoon arousal levels, as measured by the Karolinska Drowsiness Test and Alpha Attenuation Test, the effects of which continued for at least 60 minutes (1:10-2:10 PM). However, no significant differences were observed between conditions for Psychomotor Vigilance Test performance. CONCLUSIONS: Brief indoor exposure to natural bright light may decrease afternoon sleepiness. This technique of light could be used in work settings in which napping is not permitted.