New study sheds light on how night-shift work damages health

Editor's Note

A new Fred Hutchinson Cancer Research Center study finds that the body repairs DNA damage more efficiently if workers sleep during the night than if they sleep during the day. Unrepaired DNA damage can lead to cancer and other health problems.

Using urine specimens collected during night work and night sleep from a group of Seattle-area nurses, orderlies, and other hospital employees, the researchers compared levels of DNA damage in the specimens.

They found that night-shift workers had a reduced ability to repair 8-OH-dG lesions in DNA and that the effect is likely driven by melatonin suppression occurring during night work relative to night sleep.

Future studies should evaluate the use of melatonin supplementation to restore oxidative DNA damage repair in night-shift workers, the authors say.

Objectives We previously reported that compared with night sleep, day sleep among shift workers was associated with reduced urinary excretion of 8-hydroxydeoxyguanosine (8-OH-dG), potentially reflecting a reduced ability to repair 8-OH-dG lesions in DNA. We identified the absence of melatonin during day sleep as the likely causative factor.