# Inflammatory marker dynamics in shift work sleep disorder: a data-driven approach among rotating shift workers

## TL;DR

This study finds that shift work sleep disorder is linked to rising inflammatory markers over time, suggesting potential health risks for shift workers.

## Contribution

The study identifies dynamic changes in blood cell counts and inflammatory indices among rotating shift workers with sleep disorders.

## Key findings

- Participants with SWSD showed significantly increased neutrophil levels during the second year.
- Composite inflammatory indices showed consistent upward trends in the SWSD group.
- Platelet-to-lymphocyte ratio increased specifically in males with SWSD.

## Abstract

Shift work sleep disorder (SWSD) negatively affects overall health and quality of life. This cross-sectional study aimed to elucidate the association of SWSD with blood cell counts (BCCs) and related inflammatory indices over a period of 3 years.

This retrospective cross-sectional study involved rotating shift workers. Linear mixed-effects models were applied to examine the associations between group stratification (based on sex and sleep status) and longitudinal trajectories of inflammation indices.

Participants with SWSD (regardless of sex) showed significantly steeper increases in neutrophil levels during the second year (female: β = 0.079, p = 0.030; male: β = 0.076, p = 0.032). By the third year, marked changes were observed in monocyte levels, although these were not statistically significant in mixed models. Composite inflammatory indices, including the neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, systemic immune-inflammation index, systemic inflammation response index, systemic inflammatory composite index, and neutrophil-to-monocyte ratio, exhibited consistent and significant upward trends in the SWSD group (all p < 0.05, adjusted for false discovery rate). Notably, the platelet-to-lymphocyte ratio showed a sex-specific increase only in males with SWSD (β = 7.310, p = 0.006).

Long-term rotating shift workers with sleep disorders exhibited fluctuating trends in BCCs and related inflammatory indices over time, with neutrophil and monocyte counts showing increases. These patterns suggest that dynamic alterations in BCCs and related inflammatory indices are associated with circadian disruption among rotating shift workers and may have potential relevance for future risk stratification and monitoring.