Interleukin-6 Level among Shift and Night Workers in Japan: Cross-Sectional Analysis of the J-HOPE Study

Abstract

Aim: Shift workers have a high risk of cardiovascular disease (CVD). Systemic inflammation measured has been associated with the risk of CVD onset, in addition to classical risk factors. However, the association between work schedule and inflammatory cytokine levels remains unclear. The purpose of this study was to examine the association between work schedule and interleukin-6 (IL-6)/high-sensitivity C-reactive protein (hs-CRP) levels among Japanese workers.Methods: The present cross-sectional study was a part of the Japanese Study of Health, Occupation and Psychosocial Factors Related Equity (J-HOPE). A total of 5259 persons who measured inflammatory cytokine were analyzed in this study. One-way analysis of variance was used to test log-transformed IL-6/hs-CRP differences by work schedule. Multiple regression analysis was used to examine the difference adjusted for other possible CVD risk factors.Results: There were 3660 participants who had a regular work schedule; the remaining schedules were shift work without night work for 181 participants, shift work with night work for 1276 participants, and only night work for 142 participants. The unadjusted model showed that only night workers were significantly related to high levels of IL-6 compared with regular workers. Even in the multiple regression analysis, the higher level of IL-6 among only night workers remained significant (β = 0.058, P = 0.01). On the contrary, hs-CRP was not.Conclusion: The present study revealed that only night shift work is significantly associated with high levels of IL-6 in Japanese workers. These observations help us understand the mechanism for the association between work schedule and CVD onset.

Shift work, and particularly permanent night shifts, promote dyslipidaemia: A systematic review and meta-analysis

“…We included 48 studies [ [36,[53][54][55], and 12 were unspecified [17,37,38,43,49,62,67,68,75,79,81,84]. We found significantly increased blood levels of triglycerides among permanent night shift workers (0.18; 0.03 to 0.33; p = 0.017; I 2 = 73.8%), rotating 3 × 8 shift workers (0.09; 0.03 to 0.16; p = 0.004; I 2 = 73.6%), rotating 2 × 12 shift workers (0.07; 0.01 to 0.13; p = 0.017; I 2 = 31.6%), and non-specified shift workers (0.11; 0.03 to 0.18; p = 0.004; I 2 = 80.9%) (Supplementary Data 7).…”

“…We included 46 studies [10,17,23,24,37,38,40,41,43,45,[47][48][49][50][51][52][53][54][55][56][57][58][59]62,[65][66][67][68][69][70][71][73][74][75][76][77][78][79][80][81][82][83][84][85][86]91]. The overall SMD was − 0.08 (95CI − 0.12 to − 0.03; p = 0.001) with an important heterogeneity (I 2 = 85.9%) ( Fig.…”

“…2 and Supplementary Data 9). Among the 46 included studies, 6 studies reported permanent night shift [41,58,67,69,71,82] 43,45,49,62,67,68,75,79,81,84]. We found a significantly lower blood level of c-HDL among permanent night shift workers (SMD = − 0.16; 95CI − 0.32 to 0.00; p = 0.05; I 2 = 72.3%), rotating 3 × 8 shift workers (− 0.10; 95CI − 0.17 to − 0.02; p = 0.018; I 2 = 78.8%), and non-specified shift workers (− 0.08; 95CI − 0.15 to − 0.01; p = 0.027; I 2 = 81.7%).…”

Health Disparities in COVID-19: Addressing the Role of Social Determinants of Health in Immune System Dysfunction to Turn the Tide

“…Interestingly, it has also been shown that increased IL-6 levels can be found in night shift workers when compared to day shift workers, while CRP, a general marker of inflammation often measured in the clinical setting did not reveal significant differences ( 96 ). Higher IL-6 levels were also detected with sleep deprivation and fatigue ( 97 ), bullying ( 93 ), or sexual abuse ( 98 ).…”

Perfect timing: circadian rhythms, sleep, and immunity — an NIH workshop summary

“…The current focus on circadian control of immune function was presaged by the observations -first published more than 50 years ago -that circulating lymphocyte counts oscillate on a daily basis in healthy humans (27) and that the susceptibility to endotoxin depends on the time of day it is administered in rodents (28). More recent work highlights epidemiological associations between night-shift work (i.e., activity and sleep patterns in opposition to the normal day-night pattern) and elevated levels of systemic inflammatory markers (29,30). Significantly, all lymphoid organs and immune cell types tested to date harbor functional clocks (31,32).…”