Circadian gene methylation in rotating-shift nurses: a cross-sectional study

Area of Science:

• Chronobiology
• Epigenetics
• Occupational Health

Background:

• Shift work, particularly involving artificial light at night, is linked to circadian disruption.
• Understanding the epigenetic mechanisms, such as DNA methylation, is crucial for elucidating shift work's health effects.
• Circadian genes play a vital role in regulating biological rhythms and are potential targets for shift work-induced alterations.

Purpose of the Study:

• To investigate the association between rotating shift work and the DNA methylation status of circadian genes (PER1, PER2, PER3, CRY1, CRY2, BMAL1, CLOCK, NPAS2).
• To explore how current and lifetime shift work characteristics correlate with altered methylation patterns in these genes.

Main Methods:

• A cross-sectional study involving 710 female nurses and midwives in Lodz, Poland.
• Quantitative methylation polymerase chain reaction (qPCR) assays were used to measure promoter CpG methylation in selected circadian genes.
• Proportional odds regression models were employed to analyze the association between shift work and DNA methylation, adjusting for relevant covariates.

Main Results:

• Significantly decreased PER2 promoter methylation was observed in current rotating shift workers compared to day workers.
• Lower PER2 methylation correlated with a higher frequency of monthly night duties and, at borderline significance, with longer lifetime duration of shift work.
• Longer lifetime duration of shift work (>10 years) was associated with reduced PER1 methylation and BMAL1 hypomethylation.

Conclusions:

• Rotating shift work is associated with differential DNA methylation in circadian genes PER1, PER2, and BMAL1.
• These findings provide insights into the molecular mechanisms underlying the health impacts of shift work.
• Further research with larger populations is recommended to validate these epigenetic alterations in shift workers.