New night shift study sounds the alarm

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Elizabeth Newman
Elizabeth Newman

Over the years, I've heard what seems like every possible explanation for cancer. Sometimes it's cancer patients blaming themselves through questionable science  — “I was too stressed” or “I should have eaten less sugar” — and other times it's more legitimate — “She was a lifelong smoker” or “She had the BRCA1 gene.”

Many of us are always searching for the "why?" and I'm no exception. I've wondered about five out of six women living on a block near a polluted Chesapeake Bay waterway all being diagnosed with breast cancer, or whether modern newspaper printers (what are left of them) are safer for workers than they used to be. 

Cancer, of course, is almost never tied to one specific issue or event. But a new study raises alarming questions about the health of our night shift female nurses.

The analysis, published in Cancer Epidemiology, Biomarkers & Prevention (the journal of the American Association for Cancer Research) found that night shift work was associated with women having an increased risk of breast, skin and gastrointestinal cancer.

Remember, “associated” doesn't mean night shift nurses should panic. But as oncologist Xuelei Ma, Ph.D., said, “The results of this research suggest the need for health protection programs for long-term female night shift workers.”

Ma built on previous studies by analyzing long-term night shift work, looking at 114,628 cases and 3.9 million participants in North America, Europe, Australia and Asia.

A deeper analysis narrowed it down to long-term night shift work and the risk of six types of cancer.

Overall, the night shift work increased the risk of cancer by 19%. The biggest risk was skin at 41%, followed by breast at 32%. After narrowing by location, Ma found the increased risk of breast cancer was limited to female night shift workers in North America and Europe.

It's possible those women have higher sex hormone levels than those in Asia or Australia, Ma theorized, which are associated with hormone-related cancer such as breast cancer.

More bad news is comparing night shift nurses to those on the day shift. Female nurses working the night shift had a 58% increased risk of breast cancers over their day shift counterparts.

Additionally, every five years of night shift work was correlated to a 3.3% breast cancer increased risk.

The bottom line?

“Our study indicates that night shift work serves as a risk factor for common cancers in women,” said Ma. 

What this type of analysis can't answer is why. Ma theorizes that intensive night shifts may play a role. Further research, I suspect, might delve into studying whether female night shift workers and sleep problems tie into cancer risk, or night shift occupational injury risk and its associations. Let's not forget that up to a fourth of night shift nurses report going without sleep for up to 24 hours in order to adjust to working on the night shift, which should terrify you if you are a patient or an employer.

It's also worth noting that historically, both anecdotally and in studies, the definitions of “night shift” work can vary. For example, some would define “long-term” night shift work as those working during the night, which could mean a 3 p.m. to 11 p.m. shift compared to those working an 11 p.m. to 7 a.m. shift. Some nurses may regularly work nights while others may float, working three nights a month but having other shifts during the day.

But while we can dive into whether those issues make a difference, the big question in the meantime is what night shift nurses can do to mitigate potential cancer risk, and what should employers do.

One idea, as Ma suggested, is encouraging long-term night shift nurses to have regular physicals and cancer screenings. Employers that offer smoking cessation clinics, gym reimbursements or other incentives to be physically active and ways for employees to manage their weight can see it as potentially mitigating cancer risk for night shift nurses. In a medical setting, nurses should try to limit exposure to radiation.

Ultimately, though, it may come down to money. Despite how some nurses prefer the night shift due to autonomy and a quieter environment, the study should make us concerned about whether we're paying night shift nurses enough to offset potential health dangers. Night shift nurses in long-term care and hospital will always be needed, but we have to evaluate if we are doing enough to keep them healthy.

Follow Senior Editor Elizabeth Newman @TigerELN.

Daily Editors' Notes

McKnight's Daily Editors' Notes features commentary on the latest in long-term care news and issues. Entries are written by Editorial Director John O'Connor, Editor James M. Berklan, Senior Editor Elizabeth Newman and Staff Writer Marty Stempniak.