Did you know that sleeping in a room exposed to outdoor artificial light at night may increase the risk of developing diabetes? A study of nearly 100,000 Chinese adults confirmed this.
According to a study published in the journal Diabetologia, people who lived in areas of China with high nighttime light pollution were about 28% more likely to develop diabetes than people who lived in the least polluted areas.
According to the authors, outdoor light pollution at night may be responsible for more than 9 million cases of diabetes in Chinese adults aged 18 and older, which is expected to rise as more people move to cities.
However, the effects of the lack of darkness extend beyond cities. According to the authors, suburban areas and forest parks that may be tens, even hundreds of miles from the light source, may be affected by urban light pollution because it is so pervasive.
“The study confirms prior research of the potentially detrimental effects of light at night on metabolic function and risk for diabetes,” said Dr Phyllis Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University Feinberg School of Medicine in Chicago, who was not involved in the study.
Previous studies have demonstrated a connection between artificial nighttime lighting and weight gain, obesity, changes in metabolic function, insulin secretion and the onset of diabetes, and cardiovascular risk factors.
A recent study looked at the role of light in sleep for healthy adults in their twenties. During the sleep lab experiment, the young people’s blood sugar and heart rate increased after only one night of sleeping with a dim light, such as a TV set with the sound turned off.
Prior research has shown that an elevated heart rate at night is a risk factor for future heart disease and premature death, whereas higher blood sugar levels are a sign of insulin resistance, which can eventually lead to type 2 diabetes.
The new study analysed data from the 2010 China Noncommunicable Disease Surveillance Study, in which representative samples of the Chinese population were asked about social demographics, lifestyle factors, and medical and family health histories. Blood samples were taken and compared to satellite imagery of light levels in the region of China where each person lived.
The study discovered that chronic exposure to light pollution at night increased blood glucose levels, the risk of insulin resistance and diabetes.
Any direct link between diabetes and nighttime light pollution remains unknown. However, living in an urban area is known to contribute to the development of diabetes.
“It has been known for a long time now that living in an urbanised area increases your risk of obesity through increased access to high fat and convenience food, less physical activity levels due to transport links and less social activities.”