A new study found a significant link between nighttime outdoor light exposure, commonly known as light pollution, and the prevalence of Alzheimer's disease in the US.

The research was conducted by scientists at Rush University Medical Center, using satellite light pollution data and Medicare data from 2012 to 2018.

The study, funded by the National Institutes of Health and published in Frontiers in Neuroscience, found a significant link between high levels of artificial outdoor light at night and increased prevalence of Alzheimer's disease, particularly in individuals under the age of 65.

This group showed a stronger correlation between light pollution and Alzheimer's disease compared to older populations.

The analysis categorized several states based on their average nighttime light intensity, revealing a statistically significant difference in Alzheimer's disease rates between the darkest and brightest states. For example, states with the highest light pollution showed a significantly higher prevalence of Alzheimer's compared to those with minimal exposure.

Lead researcher Robin Voigt pointed out that light pollution can contribute to neuro-inflammation, disruption of circadian rhythms and sleep disturbances - factors known to play a role in the development of Alzheimer's disease.

The findings suggest that people under 65 may be particularly vulnerable to the effects of nighttime light exposure, Voigt said.

While conditions such as hypertension and diabetes are most strongly associated with Alzheimer's disease, light pollution was found to be a more significant factor than other risk contributors, including alcohol abuse, depression and obesity.

The research built on previous studies that have explored the wider health implications of light pollution, which include sleep disruption and increased risk of various health conditions.

The findings suggested that public health interventions targeting light pollution could help mitigate the risks of Alzheimer's disease, particularly in urban areas where light levels remain high despite existing regulations.

As the global population continues to urbanize and light pollution increases, the researchers stressed the need to understand its broader implications for neurodegenerative diseases.