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Scientists say excessive light pollution may increase the risk of Alzheimer’s disease, especially in the form of… … [+]
Scientists investigating the prevalence of Alzheimer’s disease have revealed that light pollution is a major risk factor.
A paper published in Boundaries today identifies a possible link between exposure to outdoor light at night and an increase in the prevalence of Alzheimer’s disease, especially among people under 65 years of age.
Alzheimer’s disease is a form of dementia that affects memory, thinking and behavior Alzheimer’s Association.
“We show that in the US there is a positive association between AD prevalence and light exposure at night, especially in people under 65 years of age,” said Dr. Robin Voigt-Zuwala, first author and associate professor at Rush University Medical Center in Chicago, Illinois. “Nighttime light pollution – a modifiable environmental factor – may be an important risk factor for AD.”
According to recent research, artificial lighting has increased globally by at least 49% in the past 25 years, but it’s also one of the easiest forms of pollution to reduce with responsible outdoor lighting.
Light intensity
Look at the light pollution map of the lower 48 US states and it is quite clear that there is a problem with artificial lighting at night. A groundbreaking study published in 2022 found that sky brightness has increased globally by seven to ten percent per year (and an average of 9.6 percent) over the past twelve years. In Europe it found that an increase in brightness of 6.5 percent per year matched the data, while in North America it was 10.4 percent.
The researchers added to these cards medical data on risk factors for Alzheimer’s disease, including alcohol abuse, chronic kidney disease, depression, obesity, diabetes, high blood pressure and stroke.
While diabetes, hypertension and stroke were more strongly associated with Alzheimer’s disease than light pollution for people aged 65 and older, for young people, higher nighttime light intensity was associated with a greater prevalence of Alzheimer’s disease than any other risk factor identified in the study was examined.
Light pollution is increasing at an alarming rate.
Lifestyle changes
All this suggests that younger people may be particularly sensitive to the effects of light exposure at night, the researchers said. “Awareness of the association should allow people – especially those with risk factors for AD – to easily make changes to their lifestyle,” Voigt-Zuwala said. “Easy changes to make include using blackout curtains or sleeping with eye masks. This is useful, especially for people living in areas with high levels of light pollution.”
There are some mitigating factors. Younger people are more likely to live in urban areas and have lifestyles that can increase light exposure at night, the researchers said, while people may not live in areas with high light pollution all their lives.
‘Plastic straw’ moment?
Is this the ‘plastic straw’ moment for light pollution? Despite years of warnings about rampant light pollution – and with more than 80% of people living under light-polluted skies – the increase in sky glow at night has been largely ignored as a public health issue.
Could the link to Alzheimer’s disease be a catalyst for limiting light pollution, just as a focus on plastic straws helped ban single-use plastics a few years ago? The movement was so successful that in 2022 the UN Environment Assembly began negotiating a Global Plastics Treaty with 170 countries to tackle plastic pollution worldwide.
One of the main reasons why light pollution is thought to be widespread is the advent of cheap LED lighting, poorly installed security lighting and unshielded motion-sensing LED lighting in homes.
I wish you clear skies and big eyes.