People who do shift work (defined as work that takes place outside of the traditional “9-to-5” workday) experience a mismatch between the body’s circadian cycle and environment1 that can potentially lead to increased risk for chronic diseases such as cardiovascular disease,2 obesity,3 type-2 diabetes,4 and cancers5 . Because of the association between shift work and age-related diseases, scientists wanted to measure the effect of shift work on a person’s epigenetic age, which is the biological age that reflects environmental influences including lifestyle, diet, and exercise.
Scientists at the National Institute of Environmental Health Sciences (NIEHS) compared the epigenetic ages of women who performed shift work to those who did not. The scientists found that for every year of shift work performed, women experienced epigenetic age acceleration of 1.2 months. This accelerated aging effect was even stronger for those who performed night shift work (defined as work done for at least one hour between midnight and 2 in the morning). Women who did shift work for more than 10 years were estimated to be biologically 3 years older than those who had never participated in shift work.
The NIEHS scientists also observed that women who participated in shift work experienced significantly different DNA methylation profiles than those who did not. DNA methylation, which is a chemical modification that influences how genes are expressed in the body, was observed to take place on genes linked to circadian rhythm and tumor susceptibility. This finding suggests that shift work can affect DNA methylation patterns across the entire genome and not just genes associated with age acceleration.
In this study, scientists showed that shift work is linked to accelerated aging and changes in the body’s DNA methylation profile. As shift work appears to be a mainstay in our society, it is important that we are aware of the potential long-term health effects and take active measures to manage the health risks of those who perform shift work.