Oxidative DNA damage during sleep periods among nightshift workers

Area of Science:

• Biochemistry
• Occupational Health
• Sleep Science

Background:

• Nightshift work is associated with potential health risks, including increased oxidative DNA damage.
• Melatonin, a key antioxidant, may be suppressed in nightshift workers, potentially increasing DNA damage.
• Limited research has explored oxidative DNA damage in nightshift worker populations.

Purpose of the Study:

• To investigate levels of oxidative DNA damage in nightshift workers compared to dayshift workers.
• To explore the relationship between melatonin levels, sleep quality, and oxidative DNA damage in nightshift workers.

Main Methods:

• Urine samples from 217 dayshift and 223 nightshift workers were analyzed for 8-hydroxydeoxyguanosine (8-OH-dG) using high-performance liquid chromatography.
• Urinary 6-sulfatoxymelatonin (aMT6s) and actigraphy-based sleep data were collected and analyzed.
• Cross-sectional study design comparing biomarker excretion between worker groups.

Main Results:

• Nightshift workers excreted significantly less 8-OH-dG during day sleep compared to dayshift workers during night sleep (77% less, p=0.03).
• Higher urinary 8-OH-dG levels in nightshift workers correlated with higher melatonin (aMT6s) levels.
• An inverse U-shaped relationship was observed between 8-OH-dG levels and sleep efficiency/duration in nightshift workers.

Conclusions:

• Reduced 8-OH-dG excretion during day sleep may indicate impaired DNA repair capacity in nightshift workers.
• Melatonin suppression and disrupted sleep quality associated with nightshift work could compromise DNA repair mechanisms.
• Further studies are needed to directly assess cellular DNA damage levels and confirm these findings.