Could Shift Work Damage Your DNA?

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Aside from the damage night shift work does to your sleep cycle, a study published in 2017 by Bhatti, et. al. has also shown that it could also cause oxidative damage to your DNA. Lack of quality sleep is one of the underlying risk factors for a variety of diseases, including heart disease and diabetes. Bhatti, et. al.’s study also suggests that it could be a risk factor for developing cancer because of an increase in a biomarker for oxidative stress and carcinogenesis, 8-OHdG. ^[1][2][3]

Studies On Sleep And Oxidative DNA Damage

Bhatti was involved in a previous study published in 2016 that focused on night shift work and oxidative DNA damage. The 2016 study focused on the sleep periods of 223 people who worked the night shift, finding that sleeping during the day after working through the night caused reduced urinary excretion of 8-OHdG. The researchers suggest that disruption of melatonin production could cause this because melatonin is known to enhance the repair of DNA damaged due to oxidative stress. ^[4]

The following year, 2017, Bhatti, et. al. published a further study. This time, the researchers focused on urinary excretion of 8-OHdG during the night shift work – (the 2016 study focused on 8-OHdG excretion during daytime sleep periods) and found the same results. This 2017 study included 50 people from the previous study, who had the biggest night differentials. The study also concluded that there was reduced urinary excretion of 8-OHdG during night shift work compared to excretion during night sleep; again reducing the ability of the body to repair DNA lesions (caused by 8-OHdG) due to reduced melatonin production. ^[1]

About 8-OHdG As A Biomarker For Damage

Valavanidis, et. al. in 2009 reported that urinary excretion of 8-OHdG is a “critical biomarker of oxidative stress and carcinogenesis”. The researchers report that oxidative damage to DNA is permanent, so finding out which substances are biomarkers can be a vital step forward in understanding, reducing and preventing damage to DNA. OHdG is also used in this manner to estimate damage to human DNA in relation to carcinogen exposure, such as tobacco smoke, asbestos, heavy metals, and hydrocarbons. The report states that OHdG is an important biomarker for cancer, which is characterized by DNA damage, mutation, and the subsequent development of cancer cells. ^[5]

The Role Of Melatonin

There are plenty of studies that focus on the effects of melatonin on DNA, particularly its ability to repair damage. One publication in 2013 by Liu, et. al. focused on how melatonin could do this, finding that it was able to improve the pathways responsible for responding to DNA damage. The researchers found that melatonin was able to alter gene expression, boosting the body’s ability to respond to DNA breakage quicker. In relation to night shift work, the more we stay awake during our regular sleep periods, the less melatonin we produce, which ultimately affects the way our body responds to DNA damage. ^[6]

Night Shift Work, Sleep Quality, And Your Health

It is not the night shift work itself that causes DNA damage and increased risk for cancer. It is the fact of staying awake during the times that we should be sleeping / “rebooting our body” that does the damage, specifically to our DNA – which thus increases our cancer risk. A lot of factors come into play, namely melatonin production and excretion of 8-OHdG, the former a substance that repairs DNA and the latter a substance that damages DNA.

Because of the nature of certain jobs (like working in a hospital or similar industries or facilities), some people may not be able to avoid night shift work completely. In order to keep the body functioning well, a healthy lifestyle is a must. Avoiding high-risk activities and habits like smoking, drinking alcohol, and a sedentary lifestyle can be ways in which we can help clear our body of free radicals, keep our DNA safe from damage and reduce our risk for cancer.