Rotating night shift work and liver enzymes-associated abnormalities among steelworkers: a cross-sectional study from a Chinese cohort.

Objective: The association between shift schedules and liver enzymes is unclear. This study aims to explore the effect of rotating night shift work on increased liver enzymes.

Methods: The in-service workers of Tangsteel Company who participated in occupational health examination in Tangshan in 2017 were selected as the research objects. Multifaceted exposure metrics of night shift work and comprehensive liver enzymes were used to evaluate rotating night shift work and liver enzymes-associated abnormalities, respectively.

Results: There were positive associations between the odds of all liver enzymes-associated abnormalities and duration of night shifts. Different exposure metrics of night shift work were significantly associated with higher odds of elevated alanine aminotransferase (ALT), elevated gamma-glutamyl transaminase (GGT) and increased liver enzymes. Compared with those who never worked night shift, the groups of current night shift, duration of night shifts ≤ 18 years, duration of night shifts > 18 years, cumulative number of night shifts ≤ 1643 nights, cumulative number of night shifts > 1643 nights and average frequency of night shifts > 7 nights/month had an OR of increased liver enzymes of 1.31 (95% CI 1.08-1.58), 1.28 (95% CI 1.05-1.58), 1.27 (95% CI 1.04-1.55), 1.28 (95% CI 1.04-1.58), 1.27 (95% CI 1.04-1.55), 1.32 (95% CI 1.08-1.60) after adjusting for all confounders, respectively. No significant association was found between rotating night shift work and liver enzymes-associated abnormalities among female steelworkers.

Conclusions: Rotating night shift work is associated with elevated ALT, elevated GGT and increased liver enzymes in male steelworkers.