Breast cancer takes the night shift

Today’s work place has notably shifted from the typical nine-to-five day enjoyed by previous generations. Be it the advent of new forms of technology or the need for 24-hour cover, the hours that employees spend at work varies considerably, perhaps none more so than in the medical field where healthcare professionals regularly work according to shifts. Just how much this could potentially affect the health of these employees, particularly their risk of developing cancer, is the subject of a new study published in Breast Cancer Research.

Dr Zienolddiny and colleagues performed a nested case-control study of 1,182 women from an initial cohort of 49,402 Norwegian nurses. From this population, a number of polymorphisms in the core circadian genes were found, which may influence the estrogen and progesterone signaling pathways, and could possibly be associated with breast cancer risk in nurses who worked three or more consecutive night shifts.

As the authors report, disrupting natural circadian rhythms has often been reported to be detrimental to health, so much so that the International Agency for Research on Cancer has classified ‘night work’ as “probably carcinogenic to humans”, perhaps due to the impact upon melatonin hormone production. So should we panic about our 24-hour lifestyle and get an early night every night?

Not quite. The researchers re-iterate that more studies into the functionality of these polymorphisms are required to understand the mechanisms involved. And with the constant demand for shift workers, there remains a wide range of possibilities for uncovering the reasons behind these observations.

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