Awake in the Dark: The link Between Shift Work and Cancer

December 4th, 2007 by

In yesterday’s post, Julie Ferguson mentioned a recent study that directly links night shift work with certain forms of cancer. The International Agency for Research on Cancer (IARC) is about to list shift work as a “probable” carcinogen. This will put shift work into the same category as anabolic steroids, ultraviolet radiation and diesel engine exhaust.
The potential number of people impacted by this designation is staggering – roughly 15 to 20 percent of the workforce in developed countries.
The scientists suspect that shift work is dangerous because it disrupts the circadian rhythm, the body’s biological clock. Light shuts down melatonin production, so people working in artificial light at night may have lower melatonin levels, which can raise their chances of developing cancer. Sleep deprivation might also be a factor. Not getting enough sleep makes your immune system vulnerable to attack and less able to fight off potentially cancerous cells.
Perhaps the most alarming finding is the impact of switching between night and day shifts: it’s probably better to work just at night and adjust accordingly. Shifting back and forth – a common practice in medical facility shift assignments – appears to compound the risks. The body’s clock is prevented from establishing a steady course.
The studies do point the way toward making shift work safer, with one relatively simple recommendation: shift workers should make sure that when they do sleep, they do so in a darkened room. The balance between light and dark is important for the body. When shift workers finally climb into bed, an (artificially) darkened room might enhance the body’s ability to generate protective melatonin.
Compensable Cancers?
What does this mean for workers comp? Not much. The comp system is notoriously conservative, slow to react and even slower to allow compensability where definitive proof is lacking. Under the prevailing standard in most states, work exposure would have to be the “predominant cause” for cancer to be compensable. A claimant would be hard pressed to prove that other risks for cancer in their lives were not significant factors in the illness: family history, lifestyle issues and other exposures. Given the general uncertainty about cancer’s origins, claims will be routinely and aggressively denied.
Our colleague Peter Rousmaniere has completed a remarkable series of articles in Risk & Insurance magazine, which graphically illustrate the inability of the comp system to confront workplace illness issues. The system balks at comprehending – and compensating – victims of illness caused by the events of 9/11, even though the “cause” — toxic dust – is pretty difficult to overlook.
Thus it is highly unlikely that shift workers with cancer will receive much of a welcome – let alone sympathy – in the comp system. They are awake for all of us, doing the jobs that must be done at night. Their “thanks” is limited to higher pay (shift differential). Their lives are disrupted, their health is apparently at risk. But when it comes to work-induced cancers, they are on their own.