Artificial light while sleeping is linked to an increased risk of diabetes

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Sleeping in a room exposed to artificial outdoor light at night may increase the risk of developing diabetes, according to a study of nearly 100,000 Chinese adults.

People who lived in areas of China with high light pollution at night were about 28 percent more likely to develop diabetes than those who lived in areas with the least light pollution, according to research published Tuesday in the journal Diabetology.

Ultimately, more than 9 million cases of diabetes in Chinese adults aged 18 and older may be attributable to nighttime outdoor light pollution, the authors said, and the number is likely to increase as more people move to cities.

However, the lack of darkness affects more than urban areas. Urban pollution is so widespread that it can affect suburbs and forested parks that may be tens or even hundreds of kilometers from the light source, the authors said.

“Studies confirm the adverse effects of nighttime light on metabolic function and diabetes risk,” said Dr. Phyllis Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University Feinberg School of Medicine in Chicago. was not involved in the study

Previous studies have shown a relationship between artificial light at night and weight gain and obesity, disruptions in metabolic function, insulin secretion and the development of diabetes and cardiovascular risk factors.

An examination published at the beginning of the year Zee and his team studied the role of light on sleep in healthy adults over the age of 20. A single night’s sleep in dim light, such as a TV with the sound off, raised blood sugar and heart rate in young adults in a sleep lab experiment.

Elevated heart rate at night has been shown in previous studies to be a risk factor for future heart disease and early death, and higher blood sugar levels are a sign of insulin resistance, which can ultimately lead to type 2 diabetes.

“Healthy sleep is very important in preventing the development of diabetes,” said Dr Gareth Nye, senior lecturer in physiology at the University of Chester in the UK. He did not participate in the Diabetology study.

“Studies have suggested that inconsistent sleep patterns have been associated with an increased risk of type 2 diabetes,” he said in a statement.

The new study used data from the 2010 China Communicable Disease Surveillance Study, which asked representative samples of the Chinese population about social demographics, lifestyle factors, and health history. Blood samples were collected and compared to satellite images of light levels in the area of ​​China where each person lived.

The study found that chronic exposure to light pollution at night raised blood glucose levels and led to an increased risk of insulin resistance and diabetes.

The direct link between diabetes and nighttime light pollution is still unclear, however, because living in an urban area itself is a known contributor to the development of diabetes, Nye explained.

“It has been known for a long time to live (in). “urbanized areas increase the risk of obesity through greater access to high-fat and convenience foods, lower levels of physical activity due to transport links, and less social activity,” Nye wrote.

Strategies to reduce light levels at night include placing your bed away from windows and using light-blocking window shades. If light levels remain low, try a sleep mask to protect your eyes.

Be aware of the type of light you have in your bedroom and ban any blue spectrum light such as that emitted by electronic devices such as televisions, smartphones, tablets and laptops; Blue light is the most stimulating type of light, Zee said.

“If you have to turn on the light for safety reasons, change the color. You want to choose lights that have more reddish or brown undertones,” he said. If a nightlight is needed, keep it dark and level with the ground so it reflects more at bed level than near your eye, she suggested.

Avoid sleeping with the TV on; if you tend to fall asleep while it’s still on, set a timer, Zee suggested.

Cut off ambient lights at least two to three hours before bed in the evening, and “if you absolutely must use the computer or other light-emitting screens, switch the screen’s light wavelengths to longer orange-amber wavelengths,” Zee said. “It is important, light during the day; daylight is healthy!”