Almost 80% of people worldwide live with light pollution. This light pollution has adversely impacted our behavior, biology, ecology, and health. Now, investigators publishing their findings in Frontiers in Neuroscience, have found that greater levels of outdoor light at night is “more strongly associated with Alzheimer’s disease prevalence in those under the age of 65 than any other disease factor examined.” 

Background:

• AD is the #1 neurodegenerative disorder
• AD = 60% to 80% of dementia cases
• AD is seen in almost 11% of those over age 65
• AD’s increase parallels light pollution’s increase

Via a combination of Medicare information and satellite data of average nighttime light intensity, researchers found a “positive relationship…between nighttime light intensity and AD prevalence for each year [2012-2018] independently.” While a modifiable environmental factor, nightly light pollution remains high despite some legislation attempts.

But why? Robin Voigt-Zuwala, PhD, lead investigator and an associate professor at Rush, states, “Certain genes can influence early-onset Alzheimer’s, and these same genes may cause increased vulnerability to the effects of nighttime light exposure. Additionally, younger people are more likely to live in urban areas and have lifestyles that may increase exposure to light at night.” Light may disrupt circadian rhythms, promoting inflammation and decreasing resilience. “The good news is that simple changes can be made with minimal effort to reduce exposure to light at night — adding black out curtains or sleeping with an eye mask.”