Excessive exposure to urban light pollution, such as street lights and neon signs, may increase the risk of Alzheimer’s, especially in people under 65.
Researchers studied light pollution in 48 U.S. states and divided the states into five groups based on the intensity of brightness.
The data was compared to the medical records of people in those states, looking for known risk factors for Alzheimer’s, such as high blood pressure and obesity.
Analysis found that more outdoor light at night was associated with a higher prevalence of the disease.
In people aged 65 and older, it appeared to have a greater influence on the development of the disease than other risk factors, such as alcohol abuse, depression and obesity.
Nearly a million people in the UK are already living with dementia, but experts believe a third of those affected have not even received a diagnosis (File)
The Alzheimer’s Society has said that dementia is the greatest health and care problem of our time
But for people under 65, it was linked to a greater risk of Alzheimer’s than any other factor in the study.
According to researchers at Rush University Medical Center in the US, this could indicate that younger people are particularly sensitive to the effects of light at night.
It’s unclear why they are more vulnerable, but it could be due to differences in light sensitivity, they add.
Dr Robin Voigt-Zuwala, first author of the study, said: ‘Night-time light pollution – a modifiable environmental factor – may be an important risk factor for Alzheimer’s disease.’
He said awareness should enable people to make simple lifestyle changes, such as using blackout curtains or sleeping with sleep masks.
The findings were published in the journal Frontiers in Neuroscience.