Graveyard Shifts Could Increase Women’s Risk of Cancer


According to a survey conducted by Centers for Disease Control and Prevention, more than 15 million working adults in America don’t have the typical nine-to-five jobs which means that these employees must report to duty in the evening and continuously work thorough the night at the risk of their health.

Experts are now saying that irregular or graveyard shifts don’t only disrupt our bodies’ natural circadian rhythm, but also increase the risk of cancer in women.

Night Shifts and Disrupted Circadian Rhythm

 Scientists agree that the time at which we sleep is just as important as sleep itself

We have often heard about the negative impacts of sitting at an office desk all day, but it turns out that working a nigh shift has even more serious health hazards than a day-time desk job. Most people think that sleep is simply a period to rest our mind and body before starting the new day afresh, but scientists say that the time at which you sleep is just as important as sleep itself.

Previous studies have already warned about the consequences of working late, saying that graveyard shifts can actually decrease workers’ life expectancy – and the effect is even worse in those who rotate their shifts and experience disrupted sleep patterns which affect their physical and cognitive performance.

Now, new research shows that women aren’t safe from the dangerous consequences of late-night shifts either. According to the study’s findings, women who worked during the night experienced a 20 per cent increase in their risk of cancer in comparison to those with typical 9-5 shifts.

Researchers also explained that the risk for developing specific cancers such as skin and lung cancer was much greater in these women who worked the graveyard shifts. The research, led by Ph.D. Xuelei Ma, was conducted at Sichuan University’s Medical Center in China and the results were published in the Cancer Epidemiology and Prevention journal.

According to the study’s findings, women who worked during the night had a 20 per cent increase in their risk of cancer

Shift Timings Can Affect Women’s Cancer Risk

The researchers used 61 previous studies on the risks of working late in the night to conduct a meta-analysis. These studies contained a collective record of 114,000 cancer cases and data from almost 4 million participants from different continents including Australia, America, Asia and Europe.

These detailed researches studied the risk of 11 different types of cancer risks associated with disrupted sleep patterns and night shifts. The researchers specifically looked into data related to female workers and what they found was an increased risk of common types of cancers due to night shifts.

Moreover, they discovered that the increase in risk depended on how long the workers had been on the night shift. Those women who had been on the graveyard shift for a prolonged period of time experienced a greater increase in their risk of specific cancers: 41 per cent increase in skin cancer risk and 18 per cent in gastrointestinal cancer – and with every addition 5 years of working on a night shift, the risk increased by 3.3%.

Different response in Different Continents

Researchers believe that the intensity and duration of the shifts could be another reason why women are exposed to a greater chance of suffering from cancer

One of the strangest findings of the study was that only late-night workers from America and Europe experienced the 3.3 per cent increase in cancer risk whereas the risk factor in Asian women showed no change. Researchers speculate that the varying risk in women from different continents may have been due to varying levels of hormones which significantly affect the risk of certain cancers.

One of the biggest groups of participants in the study was of female nurses who had worked at hospitals during the night for several years. From the analysis of this group alone, it was discovered that the risk of certain hormonal cancers was increased to a whopping 58 per cent, the risk of gastrointestinal cancer to 35 per cent and of lung cancer to 28 per cent.

Researchers believe that the reason why nurses faced a higher risk of cancer than any other late-night female workers was because of the rigorous screening that they might have gone through due to the nature of their profession. Dr. Ma also suggests that the intensity and duration of the shifts could also be another reason why these women are exposed to a greater chance of getting cancer.

The researchers stress that more protective effort needs to be made for women in professions which requires them to work at unconventional hours in order to prevent any dangerous health condition.