Epidemiologic evidence has established that shift work exposure is associated with an array of adverse health consequences, including increased risk of cardiovascular disease, gastrointestinal disease, and cancer. Investigations of the mechanisms linking shift work and disease have highlighted the importance of nocturnal light exposure and the consequent chronic disruption of circadian organization. Recent evidence that light input to the circadian system is mediated by neural systems distinct, anatomically and functionally, from those involved in vision provides a theoretical foundation for addressing this pathophysiology in shift workers. Recent work has demonstrated that the use of filtering lenses to eliminate the deep blue end of the visual spectrum (<480nm) normalizes endocrine and genetic indices of circadian organization and significantly improves nocturnal alertness and performance. The overall goal of this SBIR project is to develop spectrum-specific, indoor LED lighting solutions that provide usable indoor illumination absent the spectral components that are associated with circadian disruption. The development process will aim to achieve an optimum balance between protection of normal nocturnal physiology and color rendition by combining specially designed optical filters with the use of light sources that meet certain defined spectral requirements. Indoor lighting that could be used at night without producing circadian disruption, providing the potential for immediate improvements in alertness and performance and long-term improvements in shift worker health, would have significant potential application in the large and growing segment of the modern economy that requires night work. The development of this ZircLight lighting will be based on laboratory physiological testing, first with ZircLight prototypes based on specially selected commercially available light bulbs and custom-designed filters, and second with specially designed ceiling panels, based on LED chip arrays rather than light bulbs, which will be compatible with the common workplace lighting infrastructure. We intend to demonstrate the physiological effectiveness of these ZircLight ceiling panels in laboratory and workplace studies. This Phase II SBIR project will address three specific aims: 1) Refinement of spectral characteristics of ZircLight prototypes and testing of their physiological functionality in a laboratory shift work simulation;2) Design and fabrication of test units of 2x2 ZircLight ceiling panels and testing of physiological functionality in a laboratory shiftwork simulation;3) Evaluation of physiological effectiveness and operational functionality of ZircLight in shift work settings. The primary outcome measure for laboratory and workplace testing will be salivary melatonin, and secondary outcome parameters include salivary cortisol circadian gene expression, neurobehavioral parameters (alertness, performance, sleep, mood) and subjective light perception.

Public Health Relevance

This is a Phase II SBIR application seeking support for the development of filtered LED lighting systems for use in shift work settings. Epidemiological research suggests that light exposure during the night hours on a shift work schedule has significant adverse impact on the health of the shift worker. The disruption in internal timing caused by nocturnal light is associated with an increase in the risk of heart disease, obesity, Type II diabetes, and certain kinds of cancer. More recently, it has been shown that the harmful effects of the light may be due to a subset of the blue light fraction of the visual spectrum. By filtering this component out of the light used to illuminate shift work settings, the harmful effecs of shift work may be reduced. Studies in simulated shift work suggest that filtering out the blue light component results in normalization of the rhythms in hormone secretion (such as melatonin and cortisol) and increases in alertness and vigilance performance during the night work hours. Circadian Management Inc. is seeking SBIR support for the development and testing of LED lighting systems with switchable notch filters to remove the deleterious portion of the visual spectrum at night while providing full spectrum light during the day. These lighting systems would be used in shift work settings such as hospitals and factories to provide illumination during the night shift without the blue component while preserving color perception. If successful, this project could provide substantial health benefits for millions of US workers who are required to work the night shift on a regular basis.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Small Business Innovation Research Grants (SBIR) - Phase II (R44)
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Special Emphasis Panel (ZRG1-ETTN-A (10))
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Twery, Michael
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Circadian Management, Inc.
United States
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