Study: Light pollution may increase risk of Alzheimer’s disease

Lights out!

Researchers say exposure to bright outdoor lights at night may increase the chances of developing Alzheimer’s disease more than other risk factors, especially for young people.

“We show that in the US there is a positive relationship between [Alzheimer’s] prevalence and exposure to light at night, especially in those under the age of 65,” said Robin Voigt-Zuwala, an associate professor at Rush University Medical Center in Chicago. “Nighttime light pollution—a modifiable environmental factor—can be a significant risk factor.”

Voigt-Zuwala’s team studied maps of light pollution — such as streetlights, street lighting and illuminated signs — and divided the lowest 48 states into five groups, from lowest to highest nighttime light intensity .

Artificial light at night can disrupt the body’s 24-hour biological clock and disrupt sleep. Lack of sleep and insomnia are linked to cognitive decline.

For the elderly, Alzheimer’s prevalence had stronger associations with light pollution than risk factors such as alcohol abuse, chronic kidney disease, depression and obesity.

But diabetes, high blood pressure and stroke exceeded light pollution in that age group.

For people under 65, higher light intensity at night was associated with Alzheimer’s more than any other risk factor examined in the study.

Researchers aren’t sure why young people may be particularly sensitive to the effects of nighttime light.

They theorized that it could be their genetic makeup or that they are more likely to live in urban areas and have lifestyles that frequently expose them to outdoor light.

The study authors recommend using blackout curtains or an eye mask to block harmful light.

Their findings were published Friday in Frontiers in Neuroscience.

Although they did not study indoor light, the researchers say that blue light, such as from digital devices, has the greatest effect on sleep.

They suggest using blue light filters, replacing light bulbs with warm light and installing dimmers in the home.

Nearly 7 million Americans have been diagnosed with dementia – Alzheimer’s is the most common form of the syndrome.

The new study follows recent research that found where you live can affect your chances of getting a dementia diagnosis because of access to healthcare.