To the Editor:

In the board of education (BOE) meeting on September 23, 2013, comments were made about the installation of lighting at Chambers Field and potential health risks based on "circadian rhythm disruption."

Regardless of one's position on this issue, it is important to have a clear and factual understanding of the medical literature as it pertains to the lighting proposal. This letter is intended to provide a factual and objective interpretation of the research that was cited at the meeting.

Circadian rhythm refers to an internal body clock that regulates a 24-hour cycle of cellular processes and hormone release. Circadian rhythm disruptors have been defined as shiftwork, pregnancy, certain medications, time zone changes, and chronic changes in daily routine, where someone's nighttime is transposed into their daytime. Melatonin suppression from overexposure to nighttime lighting has been implicated as a potential cause of a higher incidence of certain cancers.

A 2007 report from the International Agency for Research in Cancer was cited at the BOE meeting. This report categorized shift work as "probably carcinogenic" in humans due to circadian rhythm disruption. This finding was relevant to persons working during the nighttime hours (nurses, factory workers, custodians, etc.) in brightly lit hospital, factory, or office settings, operating on a 24/7 basis.

Another study cited showed an increased risk of breast cancer in a group of nurses who worked the night shift over an extended period of years.

A 2012 position statement by the American Medical Association was cited as well. Richard Stevens, one of its co-authors, suggests that exposure to artificial light for prolonged periods will disrupt the body's biological clock. These conclusions were drawn from findings in situations of excessive exposure to nighttime lighting, as in repetitive and prolonged all-night exposures.

In fact, the AMA report gives no specific measures or thresholds for what is a safe or unsafe amount of nighttime exposure. One author stated that the most worrisome scenario is when a person is in a state of "constant jet lag."

It is misleading to connect findings from these studies to the Chambers lighting proposal because they are two very different lighting scenarios both in duration and intensity. The Chambers proposal consists of brief periods of lighting in evening hours over a period of months, not bright, all-night lighting year-round. Based on the findings of these studies, circadian rhythms and melatonin levels in people living near the field will not be affected by the proposed lighting. Animal studies suggest melatonin suppression requires 500-600 lux of light, and early human studies suggest that robust melatonin suppression requires a significantly higher 1500 lux. All of these studies agree that melatonin suppression from light is a function of light intensity and duration, usually starting with levels of 200 lux for over an hour.

In a Japanese study on humans, minimum light intensity needed to suppress melatonin was 285 lux for a two-hour exposure. In this study the "background" intensity of light used was 10 lux, as this amount is not believed to affect melatonin secretion at all. The homes directly adjacent to the field would be exposed to approximately 0.1–0.2 foot candle exposure, or 1-2 lux, equivalent to deep twilight. Additionally, the planned use of the lights for the turf field would predominantly be in the fall and early spring, and would not extend beyond 8:00 pm on weekdays and 10:00 pm on one Friday or Saturday night on a weekend.

There has never been a suggestion that our athletes or families living adjacent to the field would be exposed to bright, all-night lighting that would cause circadian rhythm disruption. Additionally, it is unlikely that most residents are "lights out" by 8:00 pm on weekdays or by 10:00 pm on weekends. Therefore, field lighting would create no more nighttime light exposure than what we are currently exposed to in our own kitchens or living rooms, anywhere from 50–500 lux.

As practicing physicians who live with sleep cycle disruption, we are acutely aware of the importance of maintaining circadian rhythm. However, we also have an obligation to interpret medical literature appropriately in making health-related decisions.

In this case, we believe the medical study findings are not related to the Chambers lighting proposal in that the intensity and duration of light in question are not comparable.

Without question, there are other concerns of nearby residents that should be considered, but health risk is not one of them. We will respect the final decision of the board of education and appreciate all that the board does for our school and our children.

Whatever the decision, daytime will remain daytime, and nighttime will remain nighttime in the Village of Bronxville.

Lianne M. de Serres, MD, MS
Associate Professor of Clinical Otolaryngology, New York Medical College
Director, Pediatric Otolaryngology, Maria Fareri Children's Hospital

Erica Jones, MD
Associate Professor of Clinical Medicine, Cornell School of Medicine
Director, Inpatient Telemetry Unit and Cardiology Fellowship Unit, New York-Presbyterian Hospital/Weill Cornell Medical Center

Guy M. McKhann II, MD
Associate Professor of Neurologic Surgery, New York-Presbyterian Hospital/Columbia University Medical Center

Editor's Note: MyhometownBronxville does not fact-check statements in letters to the editor, and the opinions do not necessarily reflect the thinking of its staff. Its objective in publishing letters to the editor is to give air to diverse thoughts and opinions of residents in the community.