Exposure to artificial lights may be associated with a higher risk of Alzheimer’s disease (AD), according to research published in the journal Frontiers in Neuroscience.
For the last half-century, scientists have tried to find the cause of the degenerative brain disease. The sharp increases in AD cases can be attributed to many factors, including increased lifespan, but researchers have concluded that environment is also important. Exposure to artificial light at night is one environmental factor that may influence AD, they say.
“Higher outdoor nighttime light was associated with higher prevalence of AD,” the study’s authors wrote. “While atrial fibrillation, diabetes, hyperlipidemia, hypertension, and stroke were associated more strongly with AD prevalence than nighttime light intensity, nighttime light was more strongly associated with AD prevalence than alcohol abuse, chronic kidney disease, depression, heart failure, and obesity.”
The study found that nighttime light exposure was more strongly associated with AD prevalence in those under the age of 65 than any other disease factor that was examined.
The researchers also point out that exposure to artificial outdoor light at night is associated with numerous detrimental health effects including sleep disruption, obesity, depression, anxiety, memory dysfunction, atherosclerosis, and cancer.
More research needed
To date, however, little is known about the impact of light pollution on AD, which is the most common neurodegenerative disorder and accounts for 60%–80% of dementia cases, according to the study.
The researchers cite previous studies that found people living in areas with brighter nighttime outdoor light in China and Italy have a higher risk of developing mild cognitive impairment and late-onset dementia.
Certain groups appear to be particularly sensitive to the effects of outdoor light at night: females, those with less educational attainment, and those with a lack of social activities.