Leaving blinds open at night could increase the risk of Alzheimer’s, a study suggests.
Researchers in Chicago analyzed maps of excessive light exposure, also called light pollution, in 48 states.
The team then divided them into five groups, from the lowest to the highest nighttime light intensity.
The analysis found that greater nighttime exposure to outdoor light, such as from streetlights and neon signs, was linked to a higher prevalence of Alzheimer’s than any other risk factor in people under age 65.
And for those senior citizens, nighttime light pollution seemed… have a greater influence on the development of Alzheimer’s than alcohol abuse, depression and obesity.
Excessive exposure to outdoor light at night, such as city lights filtering through the window, could increase the risk of developing Alzheimer’s disease, according to a study.
This could suggest that younger people may be particularly sensitive to the effects of light exposure at night, said the researchers, from Rush University Medical Center.
It is not clear why younger people might be more vulnerable, but it could be due to individual differences in light sensitivity, they added.
Dr Robin Voigt-Zuwala, first author of the study, said: ‘We show that in the US there is a positive association between the prevalence of Alzheimer’s disease and exposure to light at night, particularly in those under 65 years of age.
‘Nighttime light pollution, a modifiable environmental factor, may be an important risk factor for Alzheimer’s disease.’
The researchers said they hope their findings can help educate people about the potential risks of light at night.
“Awareness of the association should enable people, particularly those with risk factors for Alzheimer’s disease, to make simple lifestyle changes,” Dr Voigt-Zuwala added.
‘Some easy changes to implement include using blackout curtains or sleeping with eye masks. This is especially helpful for those living in areas with high light pollution.’
Light exposure inside the home may be as important as light exposure outside, the team added.
While the effects of indoor light were not examined in the present study, it was stated that blue light has the greatest impact on sleep. However, using blue light filters, switching to warm lighting, and installing dimmer switches in the home could effectively reduce light exposure.
The research adds to a long list of health effects of light pollution, including exposure to UV rays, which irritate the skin and increase the risk of certain types of cancer.
One Review 2021For example, overexposure to light at night has been found to increase the risk of breast cancer by 10 to 14 percent, as it suppresses melatonin production. Disruption of melatonin production has been labeled carcinogenic, particularly in the case of hormone-dependent breast cancers.
The new findings were published Friday in the journal Frontiers in Neuroscience.