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Q: There’s been a lot in the news recently regarding the health effects of artificial lighting. Can you illuminate us on the concerns and implications?
A: "All that attention to the perfect lighting, the perfect this, the perfect that, I find terribly annoying.”
-Actress Meryl Streep


There are likely days when every controlled environments facilities engineer can identify with Meryl Streep—even if your cleanroom and associated research, product development, and office spaces couldn’t be more different from a movie set. While lighting has always been a critical consideration in clean manufacturing due to process requirements, recent research and medical journal articles have cast a long shadow, raising questions about the health implications regarding the types of lighting used throughout your facility. With this new set of considerations, no one would blame any facilities engineer for confusing their work with that of a hybrid Hollywood lighting hand/physician.

What’s all the fuss about?

In June 2012, the American Medical Association (AMA) adopted recommendations regarding artificial lighting based in large part on research in a recent report entitled, “Light Pollution: Adverse Health Effects of Nighttime Lighting,” which examined the impact of artificial light on health in general and, in particular, specific diseases.

Scientific queries into the health effects of artificial lighting have been slowly gaining traction since the 1980s, and the AMA acknowledgement and adoption of recommendations regarding artificial light serves as a mainstream validation of the scientific inquiries. Many experts believe the major impact of the AMA recommendations will be to drive more research dollars into this line of inquiry, as many questions remain unanswered.

Bottom line, the AMA is recommending the development of new lighting technologies (for both indoor and outdoor lighting) to reduce health risks associated with their use and that more research be undertaken to determine the impacts of artificial light on general health and the development of specific diseases. 

An engineer’s take on the physiology in question

What’s the basis for the AMA concern? Prolonged exposure to artificial light is believed to disrupt the normal human circadian rhythm, whose alignment is in large part regulated by the natural cycle of light and dark occurring within any 24-hour period. A person’s circadian rhythm is their natural biological clock, serving the general activation of the central nervous system and a variety of cellular and biological processes, as well as the release of melatonin. Melatonin is an important biological regulator, impacting cellular level activities as well as alertness and performance. These biological rhythms and cellular processes ensure our bodies function normally. Today’s world requires extensive lighting at night, disrupting the natural rhythms that have been ruled for centuries by darkness and daylight. Various clinical and laboratory studies are reviewing the effect of artificial light and its subsequent disruption of human circadian rhythm on performance, fatigue, and disease.

Potential health impacts

The role of artificial light exposure and its disruption of a human’s circadian rhythm have raised questions about its potential impact on a host of physical conditions. Studies are either exploring—or have established links—with metabolic disorders including diabetes and obesity as well as chronic conditions of depression and mood disorders, reproductive function, and digestive and gastrointestinal problems. As the research on circadian rhythm has progressed, the link between its disruption and the list of potential diseases linked to its disruption has increased. 

Scientists continue to study the influence of melatonin disruption on the development of certain cancers, most notably breast cancer, where a number of studies have established a causal link. However, the scientific community is suggesting that circadian disruptions may play a role in other cancers, including colorectal, non-Hodgkin’s lymphoma, endometrial, ovarian, and prostate. The influence of melatonin on the development and progression of cancer is based on several cellular effects: melatonin has antioxidant properties and is anti-proliferative, functioning as an inhibitor to cancer development, as well as a modulator of tumor growth.  It should be noted that the experimental evidence linking disruption of circadian rhythms and circulating melatonin concentrations with the progression of disease is based on rodent cancer models; the human evidence is based on epidemiological studies and is indirect. The most extensive study has been undertaken in the incidence of breast cancer.

The researchers and the facilities engineer

Questions about the prolific use of electric light in the modern industrial world, and its relationship to the high rate of breast cancer here, were first raised as a causal hypothesis in 1987 in the American Journal of Epidemiology. The concept behind this theory assumed that night shift workers in the industrial world have an increased incidence of breast cancer. In 2007, based on the studies of night shift workers and cancer—mainly focused on breast cancers—the International Agency for Research on Cancer (IARC) stated that “shift work that involves circadian disruption is probably carcinogenic to humans.” 

Follow-up studies since the 2007 IARC pronouncement have been published with mixed results. One study, Night work and breast cancer risk among Norwegian nurses: Assessment by different exposure metrics, determined a significantly elevated risk when subjects regularly worked five or more night shifts consecutively before having a day off. Further, the more disruptive the type of shift, the more increased the risk. 

Other studies have placed night shift workers at higher risk for heart disease and other health problems, although research needs to more finely differentiate between the effects directly attributable to night shift versus genetic and lifestyle factors.

Much research has been undertaken examining the effects of light from various points along the color spectrum. 

Many controlled environment manufacturing facilities operate 24/7, squarely placing the issue of health risks related to artificial light sources on the desks of today’s facilities engineer.

What’s a facilities engineer to do?

The history of the industrial age is littered with examples of health impacts not initially apparent in once common manufacturing practices and materials, but stunning through the “rear view mirror” of time. As our knowledge increased, some practices were abandoned, while other procedures and materials became the basis for significant legal liabilities that cast a wide net. 

Lighting technologies continue to evolve, with more choices available – both in terms of the underlying technology and the color spectrum – every year. The facilities engineer should consider the integration of less physiologically disruptive lighting where appropriate. For example, recent studies have indicated the use of red spectrum lighting, which is less disruptive to circadian rhythms, results in the sustained reduction and stabilization of systolic and diastolic blood pressure. There may be locations appropriate for the installation of red filter sleeves over standard fluorescent lighting, typically in areas calling for background (versus task) lighting.

Bottom line: The jury is still out regarding the health impacts of artificial lighting. But the policy guidelines adopted by the American Medical Association—regarded as a conservative organization—should put every facilities engineer on notice to stay informed and consider adopting proactive measures as recommendations are developed. 


Richard Bilodeau’s 30-year career includes plant engineering positions in clean manufacturing. He has designed, operated, and supervised the construction of advanced technology facilities and engineered clean manufacturing facilities for lithium-ion batteries, medical devices, electronics, and pharmaceuticals. Contact: TheFacilitiesGuy@smrtinc.com

This article appeared in the April 2013 issue of Controlled Environments.







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