Research highlights:

• A large-scale study of residents of China’s Ningbo city, a metropolis of more than 8.2 million people, found that high exposure to artificial outdoor light at night was associated with an increased risk of conditions that affect brain health. It was found that it increases.
• Air pollution and excessive exposure to artificial bright light at night were both independently associated with increased risk of developing cerebrovascular disease and stroke.

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DALLAS, March 25, 2024 — People who continue to be exposed to bright artificial light at night may be at increased risk of developing conditions that affect blood flow to the brain and having a stroke. The research results were announced today, March 25, 2024. strokea peer-reviewed scientific journal of the American Stroke Association, a division of the American Heart Association.

Bright outdoor lighting is used at night to increase visibility of the environment and improve human safety and comfort. However, due to excessive use of artificial light, about 80% of the world’s population lives in light-polluted environments, according to the study authors.

Previous studies have linked increased exposure to bright artificial light at night to the development of cardiovascular disease, but this new study links exposure to night-time light pollution to potential risks for brain health and stroke. This is one of the first studies to investigate the relationship between

“While great progress has been made in reducing traditional cardiovascular risk factors such as smoking, obesity, and type 2 diabetes, it is important to consider environmental factors in efforts to reduce the global burden of cardiovascular disease.” said Jian-Bing Wang, one of the corresponding authors. , Ph.D., researcher at the School of Public Health and Department of Endocrinology, Zhejiang University School of Medicine Children’s Hospital and the National Child Health Clinical Research Center, Hangzhou, China.

In a study of 28,302 adults living in China, residential outdoor night light exposure was assessed using satellite imagery mapping light pollution. Stroke cases were confirmed by hospital medical records and death certificates.

Analysis of data, including six years of follow-up of participants, found that:

• 1,278 people developed cerebrovascular disease, of which 777 had ischemic (thrombus) strokes and 133 had hemorrhagic (bleeding) strokes.
• People with the highest levels of exposure to outdoor light at night had a 43% increased risk of developing cerebrovascular disease compared to those with the lowest levels of exposure.
• People with the highest levels of exposure to particulate matter 2.5 (PM)_2.5 (mainly emissions from gasoline, oil, diesel fuel, or wood combustion) had a 41% increased risk of developing cerebrovascular disease compared to participants with the lowest levels of exposure to PM._2.5.
• Participants with the highest levels of PM exposure_Ten (afternoon_Ten 50% increased risk of developing cerebrovascular disease compared to people with the least exposure to PM (mainly caused by dust and smoke)_Ten.
• Participants with the highest exposure to nitrogen oxides (emissions from cars, trucks, buses, power plants, and off-road equipment) had a higher incidence of cerebrovascular disease than those with the lowest exposure. They had a 31% higher risk of developing the disease.

Of note, additional analyzes including both nighttime outdoor light and air pollution found sustained associations with increased risk of cerebrovascular disease, with the exception of ischemic stroke.

“Our study suggests that high levels of exposure to outdoor artificial light at night may be a risk factor for cerebrovascular disease,” Wang said. “We therefore advise people, especially those living in urban areas, to consider reducing their exposure to protect themselves from potential harmful effects.”

Artificial light sources include fluorescent, incandescent, and LED light sources. Continued exposure to these light sources at night can suppress the production of melatonin, a hormone that promotes sleep. This can disrupt a person’s 24-hour body clock and disrupt sleep. The study found that compared to good sleepers, poor sleepers were more likely to have poorer cardiovascular health over time. The American Heart Association’s Life’s Essential 8 includes healthy sleep as one of eight healthy lifestyle behaviors and health measures that promote optimal cardiovascular health.

“We need more effective policies and prevention strategies to reduce the burden of disease caused by environmental factors such as light and air pollution, especially for people living in the world’s most densely populated and polluted regions. We need to develop it,” Wang said.

Research background and details:

• The analysis was conducted from 2015 to 2021 and included adults without cardiovascular disease living in Ningbo, a major port and industrial city on China’s east coast with a population of more than 8.2 million people, according to the 2020 Chinese census.
• The average age of study participants was 62 years, and approximately 60% were women.
• Participants were enrolled from 2015 to 2018 and followed for up to six years for cerebrovascular disease, ischemic stroke, and hemorrhagic stroke.
• Those with no address or error records available, those with missing covariate data (data not included in the original study that could change the results), and those with extreme levels of exposure to outdoor light at night. Those with a diagnosis of cerebrovascular disease at the time of enrollment and within 1 year after enrollment were excluded. From analysis.

The study had several limitations, including the lack of data on indoor lighting products and light-blocking measures, such as blackout curtains, that participants used at night. Additionally, satellite-based products capture very few blue light sources, which may lead to an underestimate of the association between outdoor light at night and cerebrovascular disease. Additionally, because the population studied was from a city in China, the results may not apply to people in other communities with different nighttime outdoor light exposures. Larger prospective studies are needed to confirm these findings.

Co-authors, disclosure information, and funding sources are listed in the manuscript.

The study, published in the scientific journal of the American Heart Association, is peer-reviewed. The statements and conclusions in each manuscript are solely the opinions of the study authors and do not necessarily reflect the policy or position of the Society. The Association makes no representations or warranties regarding its accuracy or reliability. The association is primarily funded by individuals. Foundations and corporations (including pharmaceuticals, device manufacturers, and other companies) also make contributions, which help fund specific programs and events for the association. The Society has strict policies in place to ensure that these relationships do not influence scientific content. Revenues from pharmaceutical companies, biotech companies, device manufacturers, health insurance companies, and the association’s overall financial information can be found here.

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