Shift work DOES increase your risk of cancer – and your disrupted sleep patterns are to blame
More than 3.5 million people work irregular hours in the UK - and all of them are at greater risk of cancer, experts warn
We are, as a nation, working longer hours and increasingly unsociable hours.
But, according to new research, the knock-on effects to our health may be more than just a nagging desire to sleep in.
On the contrary, scientists at in California say they've found a direct link between cancer growth and the proteins that regulate our body clock.
The research, published in the journal Molecular Cell, focused on proteins called cryptochromes.
It suggests that when our sleep pattern is regularly disturbed over long periods of time it leaves a cancer-linked protein, called cMYC, running free.
This is usually kept in check by a secondary protein, called CRY2, but - because it senses light and repairs DNA damage caused by sunlight - they're less present in shift workers who sleep during the day.
The latest finding adds to the growing body of evidence that long-haul travel and working shift patterns can raise a person's cancer risk.
"This appears to have big implications for the connection between circadian rhythms and cancer," said TSRI biologist Katja Lamia, senior author of the study.
"We know this connection exists, but we haven't known why."
Why are shift workers likely to be less healthy?
According to NHS Direct, there are a number of potential underlying factors that may impact on health and wellbeing.
Firstly, shift working can disrupt what are known as circadian rhythms, the internal "body clock". This can disrupt the normal workings of a hormone called melatonin. This disruption can lead to poor sleep and chronic fatigue.
Persistent lack of good quality sleep has been linked to a range of chronic conditions such as obesity, depression, diabetes and heart disease.
While the body can slowly adapt to the changes in working patterns, many shift workers are on rotating shifts and suddenly switching from a night to day shift leads to further disruptions.
Rotating shift work can also disrupt the production of insulin, which may increase the risk of someone developing type 2 diabetes.
There is also the fact that shift workers tend to be on the lower end of the socioeconomic scale. And there is evidence that people on lower incomes have an increased tendency to smoke, drink excessive amounts of alcohol and eat a poor diet. There is also the stress and worry associated with trying to make ends meet.
"This is a function of a circadian protein that has never been seen before," said TSRI Research Associate Anne-Laure Huber, who served as first author of the study.
The researchers say more studies are needed to confirm this connection between circadian clocks and cancer in human tissues.
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But this isn't the first time shift work has been linked to diminished health.
In 2007, a also suggested that night shifts were a likely cause of cancers.
Earlier this year, scientists discovered that our spinal discs have a 24-hour clock that, when malfunctioning, can trigger aches.
The team from Manchester University said a good sleep at night will help protect the clock and alleviate age-related issues.
They also say people should avoid working at night or to work fixed hours rather than a rotating shift pattern to combat the issue.