Exposure to outdoor light at night may lead to an increased risk of developing Alzheimer’s disease, particularly in those under 65.
- Exposure to outdoor light at night may increase the prevalence of Alzheimer’s disease, a new study suggests.
- The effect would be greater than many other risk factors, especially in people under 65.
- Researchers recommend using blackout curtains or wearing an eye mask while sleeping.
Street lights, traffic lights, road lighting, shop signs… dark nights no longer exist in some parts of the world. This nocturnal light pollution could put brain health at risk.
Researchers at Rush University Medical Center have found that it may be a significant risk factor for Alzheimer’s disease. The study was published in the journal Frontiers in Neuroscience.
Alzheimer’s disease and night light: a very significant impact on young people
To determine the effect of nighttime light exposure, the scientists studied light pollution maps of the 48 contiguous US states. They established five groups from lowest to highest nighttime light intensity. They then incorporated medical data from the population.
Results of their analyses: In those aged 65 and over, the prevalence of Alzheimer’s disease was more strongly correlated with nighttime light pollution than with other risk factors such as alcohol abuse, chronic kidney disease, depression and obesity. In contrast, diabetes, high blood pressure and stroke were more associated with the disease than exposure to artificial light.
For people under 65, the risks were different. High nighttime light intensity was linked to a greater increase in the risk of Alzheimer’s disease than all other factors. “This would suggest that young people may be particularly sensitive to the effects of nighttime light exposure.”explain the researchers in their press release.
The mechanisms at play behind this vulnerability to light pollution are not yet understood. Dr Robin Voigt-Zuwala, first author, puts forward a hypothesis. “Certain genotypes, which influence the early onset of Alzheimer’s disease, impact the response to biological stressors. This could explain an increased vulnerability to the effects of exposure to nighttime light. In addition, young people are more likely to live in urban areas and have lifestyles that may increase their exposure to light at night.”
Curtains and masks help combat light pollution
While the association between light pollution and increased risk of Alzheimer’s disease has not been fully understood, the researchers hope their work will raise awareness of the health risks of excessive nighttime light. Dr. Robin Voigt-Zuwala points out that simple actions can reduce exposure to lighting.
“Easy changes to implement include using blackout curtains or wearing an eye mask to sleep. This is especially helpful for those who live in areas with high light pollution.”
Furthermore, although he has not specifically studied the effects of screens on brain health, the expert calls for caution when it comes to blue light. The latter has a strong impact on sleep, “Using blue light filters, switching to warm light and installing dimmers in the home could effectively reduce exposure to light”he specifies.
