Overexposure to light pollution at night may increase the risk of acquiring Alzheimer’s. In a recent study, researchers discovered that light pollution had a stronger link with Alzheimer’s prevalence in adults aged 65 and younger than any other risk factor investigated.
Light pollution affects around 80% of the world’s population and is associated with several health issues, including sleep disorders, anxiety, and fatigue [1, 2] .
According to a recent study, there may be a substantial increase in Alzheimer’s risk due to light pollution [3] .
Numerous risk factors are known to increase the likelihood of getting Alzheimer’s. These include lifestyle choices like smoking and drinking alcohol , as well as medical disorders like diabetes , high blood pressure , and heart disease. This latest study provides compelling evidence that light pollution is an additional risk factor for the condition.
Frontiers in Neuroscience published the study.
Brighter Nights May Increase Alzheimer’s Risk: The Study
The study’s authors investigated satellite data to ascertain the average nighttime light intensity in the United States from 2012 to 2018.
They ranked the lower 48 states based on the average nighttime light intensity. They then divided the states into five groups, ranging from the ones with the lowest average nighttime light intensity to those with the highest average nighttime light intensity.
The researchers also collected Medicare data to evaluate Alzheimer’s prevalence in each state.
They discovered statistical disparities between states that were the darkest and the brightest at night. There was a positive correlation between the prevalence of Alzheimer’s disease and higher levels of light pollution at night.
The research team observed the effect in people under and over 65, men and women , and all races except Asian Pacific Islanders.
They discovered that, compared to other possible disease risk factors such as chronic kidney disease, alcohol abuse, depression, and obesity, nocturnal light pollution showed a stronger link with the occurrence of Alzheimer’s in adults 65 years of age and older.
However, for this group, some risk factors were more strongly associated with Alzheimer’s disease than light pollution, which included diabetes , stroke, and hypertension .
In people under the age of 65, the study authors discovered that higher levels of nighttime light pollution were related to a higher prevalence of Alzheimer’s than any other risk factor investigated.
Limitations of the Study
As with other studies, it is critical to acknowledge that this research has limitations. Some factors were not controlled for in this investigation, which may have affected the outcomes.
For example, the study did not measure artificial indoor light, such as that emitted by phones, televisions, and other electronic devices. Such factors are also linked to sleep problems and may influence the outcomes.
Another factor the team did not adjust and may have influenced the results is the impact of air pollution . Light pollution has a connection to air pollution since brightly lit places are often present in busier urban centers. These metropolitan settings have more vehicle traffic, industrial activity, and trash disposal. All of this contributes to higher concentrations of dangerous particulate matter, which is linked to dementia and cognitive decline.
Furthermore, the study’s data was limited to the US population. The analysis did not include health and socioeconomic status disparities, which are significant risk factors for Alzheimer’s and may have played a role.
Also, the study only looked at Alzheimer’s prevalence rather than incidence, and the Medicare data was limited.
However, this is not the first study to find a link between nighttime light pollution and cognitive health.
Previous studies have also found a link between dementia and nighttime light pollution. According to studies conducted in China and Italy, people who live in areas with high levels of light pollution are more likely to acquire moderate cognitive impairment and late-onset dementia [4, 5] . The most recent study broadens the body of data by demonstrating a direct correlation between light pollution and Alzheimer’s disease [3].
Studies have also indicated a connection between light pollution and Parkinson’s disease [6] .
Sleep: A Significant Risk Factor
The specific reason why nighttime light pollution is associated with an increased Alzheimer’s risk remains unknown. However, it might have something to do with how light pollution ruins sleep.
Sleep plays a significant part in dementia development. According to research, getting too little sleep can harm the brain’s glymphatic system, which is a network of vessels that helps remove waste and flush out the harmful proteins that are assumed to accumulate and lead to Alzheimer’s [7] . There is a theory that these proteins don’t get washed away and continue to build up when we don’t get enough sleep.
Nighttime light exposure can potentially interfere with a person’s circadian rhythm. This internal brain clock regulates our sleep and wake cycles by adjusting to variations in the light surrounding us. Disturbing this cycle might lead to inflammation and make a person more prone to illness. Such inflammation can lead to a rise in amyloid, a harmful protein usually present in the brains of Alzheimer’s patients .
Other Risk Factors for Alzheimer’s
The precise cause of Alzheimer’s in the majority of cases remains unclear. However, scientists think it’s probably an intricate combination of lifestyle, health, and hereditary factors in addition to age-related brain changes.
Some risk factors, such as age and family history, are unchangeable. Nonetheless, there may be ways to change a few risk factors linked to Alzheimer’s.
These include unhealthy eating habits, poor sleep , smoking, alcohol abuse, physical inactivity, social isolation, and a lack of mental stimulation.
Awareness Can Help
The researchers observe that in some parts of the world, particularly urban areas, lights never go off.
They said up to 80% of the world’s population suffers from light pollution, which prevents most individuals living in urban and suburban regions from seeing the natural celestial light. Even though most people believe that artificial light at night is safe or even helpful, light pollution has adverse effects on the environment, human behavior, biology, and health.
The researchers intend to increase public awareness of the potential hazards related to nighttime light exposure with their findings.
Robin Voigt-Zuwala, Ph.D., first author of the study and an associate professor at Rush University Medical Center, stated in a press release that Understanding the link should enable people to easily modify their lifestyle, especially those who have risk factors for Alzheimer’s. Using eye masks when sleeping or utilizing blackout curtains are simple adjustments. Those who live in places with high levels of light pollution will find this very helpful [8] .
Alzheimer’s Research Association is a non-profit organization dedicated to helping caregivers of Alzheimer’s disease and dementia. We provide the latest information and news about the illness and helpful tips to help caregivers cope with their daily caregiving challenges. We realize the most important thing that a caregiver needs is financial assistance. Therefore, we provide grants to caregivers to ease their financial burden. Caregivers can apply for grants here: Alzheimer’s Grant Application .
You can also help caregivers in their endeavor by donating as much as possible: Donation To Alzheimer’s Research Associations .
References
- Falchi, F., Cinzano, P., Duriscoe, D., Kyba, C.C., Elvidge, C.D., Baugh, K., Portnov, B.A., Rybnikova, N.A. and Furgoni, R., 2016. The new world atlas of artificial night sky brightness. Science advances, 2(6), p.e1600377.
- Chepesiuk, R., 2009. Missing the dark: health effects of light pollution. Environ Health Perspect., 117(1), A20–A27.
- Voigt, R.M., Ouyang, B. and Keshavarzian, A., 2024. Outdoor Nighttime Light Exposure (Light Pollution) is Associated with Alzheimer’s Disease. medRxiv.
- Chen, Y., Tan, J., Liu, Y., Dong, G.H., Yang, B.Y., Li, N., Wang, L., Chen, G., Li, S. and Guo, Y., 2022. Long-term exposure to outdoor light at night and mild cognitive impairment: a nationwide study in Chinese veterans. Science of the total environment, 847, p.157441.
- Mazzoleni, E., Vinceti, M., Costanzini, S., Garuti, C., Adani, G., Vinceti, G., Zamboni, G., Tondelli, M., Galli, C., Salemme, S. and Teggi, S., 2023. Outdoor artificial light at night and risk of early-onset dementia: A case-control study in the Modena population, Northern Italy. Heliyon, 9(7).
- Romeo, S., Viaggi, C., Di Camillo, D., Willis, A.W., Lozzi, L., Rocchi, C., Capannolo, M., Aloisi, G., Vaglini, F., Maccarone, R. and Caleo, M., 2013. Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson’s disease epidemiology. Scientific Reports, 3(1), p.1395.
- Buccellato, F.R., D’Anca, M., Serpente, M., Arighi, A. and Galimberti, D., 2022. The role of glymphatic system in Alzheimer’s and Parkinson’s disease pathogenesis. Biomedicines, 10(9), p.2261.
- Excessive light pollution may increase risk of Alzheimer’s, especially in younger people. EurekAlert. News Release. https://www.eurekalert.org/news-releases/1054593. Published Online: 6th September, 2024. Accessed: 1st October, 2024.
- Why light pollution may be linked to greater risk of Alzheimer’s disease. The Conversation. https://theconversation.com/why-light-pollution-may-be-linked-to-greater-risk-of-alzheimers-disease-238942. Published Online: 18th September, 2024. Accessed: 1st October, 2024.
- Alzheimer’s risk in younger people linked to nightly light pollution in new study. Medical News Today. https://www.medicalnewstoday.com/articles/higher-alzheimers-risk-younger-people-linked-nightly-light-pollution-study. Published Online: 6th September, 2024. Accessed: 1st October, 2024.