Sunday, August 14, 2016

Nighttime light - how it might affect hospitalized patients

While searching for some articles on melatonin use by breast cancer survivors, I learned a while back that female shift workers, that is workers who are exposed to light during "non-traditional" times, have a higher incidence of breast cancer that is likely related to disruption in their circadian rhythms. While there is still a lot of research being done, a 2014 article in CA: a cancer journal for clinicians [Stevens RG, Brainard GC, Blask DE, Lockley SW, Motta ME. Breast cancer and circadian disruption from electric lighting in the modern world. CA Cancer J Clin. 2014 May-Jun;64(3):207-18. doi: 10.3322/caac.21218] had this to say:

  • "It is now clear that electric lighting, including indoor evening light levels, has strong effects on human circadian rhythms in physiology, metabolism, and behavior. Recent experimental evidence in humans has shown, for example, that the lighting commonly used in the typical home in the evening is enough to delay melatonin onset and blunt its nocturnal peak (36).... It is not certain that these alterations can, in fact, increase breast cancer risk; that evidence is accumulating but is not yet conclusive. However, chronic disruption of circadian rhythmicity has the potential to yield serious long term health consequences".  
Today a short article in the NYT [Excess Light Exposure May Take Toll on Muscles and Bones] mentioned how this incident night-time light might affect patients in the hospital. A very interesting and thought-provoking point is made by Dr. Colwell. If many of our hospitals are "quiet zones" at night, why can't they be "dark zones" as well? 

  • "While the findings of a rat study can’t be translated directly to human health, the data suggest more research is needed into the health effects of artificial light. One concern is the health of patients in hospital intensive care units, elderly people in nursing homes and babies in neonatal units — places where artificial lights often are kept on for 24 hours a day....“We keep the sickest people in our society under constant light conditions,” said Dr. Colwell."

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