Excessive exposure to light pollution at night has been linked to an increased risk of developing Alzheimer’s disease, especially for individuals under the age of 65. Research published in Frontiers in Neuroscience found that exposure to light pollution may be an important modifiable risk factor to investigate in Alzheimer’s disease. The study, led by Robin Voigt-Zuwala, Ph.D., a researcher at Rush University Medical Center, used data from satellites to determine average nighttime light intensity in the U.S. between 2012-2018. They then compared these findings to Medicare data on the prevalence of Alzheimer’s disease in different states.
The researchers found that there was a positive association between Alzheimer’s prevalence and exposure to light at night, particularly in those under 65. States with higher intensity of light pollution had a greater prevalence of Alzheimer’s disease. This effect held true for both men and women, as well as for all races except for Asian Pacific Islanders. Individuals under 65 had a stronger correlation between nighttime light pollution and Alzheimer’s prevalence compared to other risk factors studied. However, those over 65 still showed a significant association between light pollution and Alzheimer’s disease.
While the study authors acknowledge some limitations in their research, such as limited Medicare data and the lack of indoor light exposure data, they stress the importance of considering both outdoor and indoor nighttime light exposure when studying Alzheimer’s disease. Nikki-Anne Wilson, Ph.D., a Postdoctoral Research Fellow at the University of New South Wales, points out that while it remains to be seen if nighttime light exposure is truly a risk factor for Alzheimer’s, sleep disruption may play a critical role in the development of the disease. Wilson emphasizes the importance of good sleep habits and suggests simple ways to improve sleep quality.
In the United States, approximately 6.9 million Americans aged 65 and older live with Alzheimer’s disease, with many cases occurring in individuals over 75. While the exact cause of Alzheimer’s is not fully understood, it is believed to be a complex combination of genetic, health, lifestyle, and age-related factors. Some risk factors, such as age and family history, cannot be changed, but modifiable risk factors like smoking, physical inactivity, poor sleep, unhealthy diet, and lack of mental stimulation may be associated with the disease. More research is needed to determine if nighttime light exposure is a risk factor for Alzheimer’s, as it is not currently accepted as such by neurologists.
The researchers highlight the widespread issue of light pollution in urban and suburban areas, where artificial lights may disrupt natural celestial light. They stress the detrimental ecological, behavioral, biological, and health consequences of light pollution and hope their findings raise awareness of the possible risks associated with nighttime light exposure. Voigt-Zuwala suggests simple lifestyle changes, such as using blackout curtains or sleeping with eye masks, to reduce exposure to light pollution and potentially lower the risk of Alzheimer’s disease. While more research is needed to fully understand the impact of nighttime light on Alzheimer’s, these findings open up new avenues for investigating modifiable risk factors for the disease and promoting healthy sleep habits.
