How Nighttime Light Pollution May Affect Alzheimer’s Risk

Recent studies have revealed that nighttime light exposure may raise the risk of Alzheimer's disease, particularly among people younger than 65. Nighttime light can disrupt circadian rhythms and cause sleep disturbances, both of which are recognized as risk factors for neurodegenerative conditions. Alarmingly, excessive or inefficient artificial outdoor lighting, known as light pollution, affects 80% of the global population. Researchers are now exploring the links between outdoor night light pollution and Alzheimer's disease.

In many parts of the world, artificial lights illuminate the night continuously. While streetlights, roadway illumination, and bright signage can improve safety and deter crime, they also bring behavioral and health repercussions. In the US, some states have enacted laws to curb light pollution, yet many areas still experience high levels of nighttime illumination.

The researchers analyzed satellite data to measure the average nighttime light intensity across the U.S. from 2012 to 2018. They also integrated medical data on variables that are known or suspected to be risk factors for Alzheimer's disease into their study. They created a dataset detailing nighttime light intensity for each state, categorizing them into five tiers ranging from the lowest to the highest levels of light exposure at night.

The study uncovered significant statistical differences in Alzheimer's disease prevalence between the states with the lowest and highest levels of nighttime light. There was a clear positive correlation between higher levels of nighttime light pollution and increased Alzheimer's disease prevalence, a trend that persisted across all age groups and both genders. Notably, for individuals under the age of 65, nighttime light intensity was a more significant risk factor for Alzheimer’s disease than any other factor examined, suggesting that younger populations might be especially vulnerable to the effects of nighttime light exposure.

The researchers hope their findings raise awareness about the potential risks associated with nighttime light exposure. By understanding the link between light at night and Alzheimer's disease, individuals, particularly those already at risk for AD, can take simple measures to mitigate these risks. Implementing changes such as using blackout curtains or wearing eye masks can be particularly beneficial for residents in areas with high levels of light pollution.

To view the original scientific study click below:
Outdoor nighttime light exposure (light pollution) is associated with Alzheimer’s disease