Exposure to excessive light pollution at night may increase the risk of developing Alzheimer’s disease, especially in individuals under the age of 65. A study published in Frontiers in Neuroscience found a positive association between Alzheimer’s prevalence and exposure to light at night in the United States. The researchers used satellite data to determine average nighttime light intensity from 2012-2018 and found that states with higher intensity of light pollution also had higher prevalence of Alzheimer’s disease. While the study has limitations, such as limited Medicare data and lack of indoor light exposure data, the findings suggest that nighttime light pollution may be a modifiable risk factor to investigate further in Alzheimer’s disease research.
Nighttime light exposure may impact Alzheimer’s disease through mechanisms such as sleep disruption, which plays a crucial role in clearing amyloid-beta protein associated with the disease from the brain. Poor sleep quality due to light pollution or untreated sleep disorders like sleep apnea may reduce the brain’s ability to remove this protein, contributing to the development of Alzheimer’s. While more research is needed to confirm if nighttime light exposure is a true risk factor for the disease, developing good sleep habits and limiting screen time before bed may have broader health benefits and potentially reduce the risk of Alzheimer’s.
In the United States, millions of Americans aged 65 and older live with Alzheimer’s disease, with age-related changes in the brain and complex combinations of genetic, health, and lifestyle factors believed to contribute to its development. While some risk factors like age and family history cannot be changed, others such as smoking, alcohol misuse, physical inactivity, poor sleep, unhealthy diet, social isolation, and lack of mental stimulation may be modifiable. The study authors emphasize the importance of considering both outdoor and indoor nighttime light exposure in understanding the impact of light pollution on Alzheimer’s disease risk, as well as empowering individuals to make simple lifestyle changes like using blackout curtains or sleeping with eye masks in areas with high light pollution.
Although nighttime light exposure is not currently considered an accepted risk factor for dementia by neurologists, the study findings raise awareness of the potential risks associated with light pollution. Researchers note that artificial light at night is prevalent in many urban and suburban areas, with up to 80% of the global population experiencing light pollution. While some may view nighttime artificial light as harmless or beneficial for safety, it can have ecological, behavioral, biological, and health consequences. By highlighting the association between nighttime light pollution and Alzheimer’s disease prevalence, the study aims to encourage individuals, especially those at risk for Alzheimer’s, to make lifestyle changes such as using blackout curtains or eye masks to reduce exposure to excessive light at night.
As research investigating dementia and factors contributing to its development continues to evolve, it remains unclear whether light pollution may directly contribute to dementia risk. However, maintaining good sleep habits and addressing sleep disorders are associated with broader health benefits and may play a crucial role in reducing the risk of Alzheimer’s disease. The impact of sleep disruption on brain processes, including the clearance of amyloid-beta protein, underscores the importance of understanding how nighttime light exposure can affect sleep quality and overall brain health. While more research is needed to fully determine the relationship between nighttime light pollution and Alzheimer’s disease risk, developing healthy sleep habits and addressing potential sleep disorders may be key factors in reducing the risk of developing dementia.
