High exposure to artificial outdoor night light may raise risk of stroke

By Sharin Hussain via SWNS

High exposure to artificial outdoor light at night increases the risk of a stroke by 50 percent, warns a new study.

Researchers found that air pollution and night-time outdoor lights were associated with harmful effects on the brain.

The study, published in the journal Stroke, reveals that excessive use of artificial light has resulted in about 80 percent of the world's population living in light-polluted environments.

Dr. Jian-Bing Wang, of Zhejiang University School of Medicine, said: “Despite significant advances in reducing traditional cardiovascular risk factors such as smoking, obesity and Type 2 diabetes, it is important to consider environmental factors in our efforts to decrease the global burden of cardiovascular disease.”

Researchers looked at information from more than 28,000 adults living in Ningbo, China, over the course of six years who were exposed to residential outdoor night-time light.

This data was gathered from 2015 to 2021, with the average age of the participants being 62. They were assessed by satellite images that mapped light pollution.

Cases of stroke were confirmed by hospital medical records and death certificates.

The analysis found that 1,278 people developed cerebrovascular disease, which affects the blood flow to the brain. This includes 777 clot-caused strokes and 133 hemorrhagic bleeding strokes.

The exposure to higher levels of the night outdoor light had a 43% increased risk of developing cerebrovascular disease.

People with the highest levels of exposure to particulate matter (PM) of 2.5, emissions from the combustion of gasoline, oil or wood had a 41 percent increased risk of developing cerebrovascular disease. There was an increased risk of 50 percent for PM10.

High exposure to nitrogen oxide, emissions from cars and power plants, had a 31 percent risk of developing the disease.

Dr. Wang said: “Our study suggests that higher levels of exposure to outdoor artificial light at night may be a risk factor for cerebrovascular disease.

“Therefore, we advise people, especially those living in urban areas, to consider reducing that exposure to protect themselves from its potential harmful impact.”

Light sources, like fluorescent and incandescent at night can suppress melatonin production, a hormone that promotes sleep.

This can disrupt the 24-hour internal clock in people and impair sleep.

Sleep-deprived people are more likely to experience worse cardiovascular health over time, according to the study.

Dr. Wang added: “We need to develop more effective policies and prevention strategies to reduce the burden of disease from environmental factors such as light as well as air pollution, particularly for people living in the most densely populated, polluted areas around the world.”