Researchers have found a significant link between artificial outdoor light and insomnia. Exposure to light pollution was associated with an increased number of prescriptions for sleeping pills, also known as hypnotic drugs.
The effect of artificial outdoor light appeared to be the greatest among older adults, who were found to be more likely to use higher daily doses of hypnotic drugs or used them for longer periods of time.
Study co-author Dr. Kyoung-bok Min is an associate professor in the Department of Occupational and Environmental Medicine at Seoul National University College of Medicine in South Korea.
“This study observed a significant association between the intensity of outdoor, artificial, nighttime lighting and the prevalence of insomnia as indicated by hypnotic agent prescriptions for older adults in South Korea,” said Dr. Min. “Our results are supportive data that outdoor, artificial, nighttime light could be linked to sleep deprivation among those while inside the house.”
According to the American Academy of Sleep Medicine, symptoms of insomnia include struggling to fall asleep, having trouble maintaining sleep, or waking up too early. Environmental factors such as noise and light pollution or extreme temperatures can disrupt sleep among most people.
A growing collection of research is reporting on how exposure to excessive lighting at night can affect human health. Whether indoors or outdoors, light pollution can disrupt circadian rhythms, which can lead to many different chronic diseases such as cancer and diabetes.
The current study was focused on data from the 2002-2013 National Health Insurance Service-National Sample Cohort (NHIS-NSC) in South Korea. After eliminating any respondents who had been diagnosed with a sleep disorder, the study sample included 52,027 adults who were at least 60 years old.
To determine an individual’s exposure to light pollution, the team used satellite data provided by the National Centers for Environmental Information. The researchers also used health insurance records to evaluate the use of two hypnotic drugs, zolpidem and triazolam, and found that about 22 percent of study participants had prescriptions to treat insomnia.
“Given the recent scientific evidence including our results, bright outdoor lighting may be a novel risk factor for prescribing hypnotic drugs,” said Dr. Min.
He also pointed out that public health officials seem to be less concerned with light pollution than with other environmental pollutants. However, this study provides even more evidence of a link between light pollution and negative health outcomes.
The research is published in the Journal of Clinical Sleep Medicine.
By Chrissy Sexton, Earth.com Staff Writer