RT Journal Article
SR Electronic
T1 Night shift work and abnormal liver function: is non-alcohol fatty liver a necessary mediator?
JF Occupational and Environmental Medicine
JO Occup Environ Med
FD BMJ Publishing Group Ltd
SP 83
OP 89
DO 10.1136/oemed-2018-105273
VO 76
IS 2
A1 Feng Wang
A1 Liuzhuo Zhang
A1 Suyang Wu
A1 Wentao Li
A1 Miaomiao Sun
A1 Wenting Feng
A1 Ding Ding
A1 Samuel Yeung-shan Wong
A1 Peng Zhu
A1 Greg J Evans
A1 Yun Kwok Wing
A1 Jihui Zhang
A1 Jelle J Vlaanderen
A1 Roel C H Vermeulen
A1 Yanfang Zhang
A1 Emily Ying-yang Chan
A1 Zhimin Li
A1 Lap Ah Tse
YR 2019
UL http://oem.bmj.com/content/76/2/83.abstract
AB Objectives Accumulated evidence implies that night shift work may trigger liver dysfunction. Non-alcoholic fatty liver (NAFL) is suggested to be a necessary mediator in this process. This study aimed to examine the relationship between night shift work and elevated level of alanine transaminase (e-ALT) of workers and investigate the potential mediation effect of NAFL.Methods This study included all male workers from the baseline survey of a cohort of night shift workers. Information on demographics, lifestyle and lifetime working schedule was collected by face-to-face interview. Liver sonography was used to identify NAFL cases. Serum ALT level was detected by an automatic biochemical analyser. e-ALT was defined as ALT >40 U/L. Logistic regression models were used to evaluate ORs, and mediation analysis was employed to examine the mediation effect.Results Among 4740 male workers, 39.5% were night shift workers. Night shift workers had an increased risk of e-ALT (OR, 1.19, 95% CI 1.00 to 1.42). With the increase in night shift years, the OR of e-ALT increased from 1.03 (95% CI 0.77 to 1.36) to 1.60 (95% CI 1.08 to 2.39) among workers without NAFL. A similar trend was not found among workers with NAFL. In addition, no significant mediation effect of NAFL in the association between night shift work and e-ALT was found.Conclusions Night shift work is positively associated with abnormal liver function, in particular among workers without NAFL. Shift work involving circadian disruption is likely to exert a direct effect on liver dysfunction rather than rely on the mediation effect of NAFL.