ow can artificial light impact people's health? Their exposure night may lead to problems with glucose control and increased diabetes risk, researchers have now found.

For their study, published in Diabetologia, a team of researchers used data from the China disease surveillance study, which included samples of 98,658 participants. They also looked at the participants' exposure to artificial light at night (LAN).

"Our aim was to estimate the associations of chronic exposure to outdoor LAN with glucose homoeostasis markers and diabetes prevalence based on a national and cross-sectional survey of the general population in China," the researchers wrote.

Exposure to artificial light has been a major issue in modern societies. It has disrupted the circadian rhythms of insects and animals and has had impacts on both animal and human health. For instance, rats exposed to artificial LAN developed glucose intolerance, as well as elevated insulin and blood sugar, researchers said. And in humans, night shift workers who were frequently exposed to bright LAN had disrupted circadian rhythms and higher risks for coronary heart disease.

In China, the "rapid urbanization and economic growth" has led to an increase in such lighting and, in turn, more and more people end up getting exposed to it.

For the study, the participants were recruited from 162 study sites – all of whom had been living there for at least six years. Researchers found that chronic exposure to higher-intensity outdoor LAN was "significantly associated" with a 28% increase in the prevalence of diabetes compared to areas with the lowest exposures. It was also associated with an "increased risk of impaired glucose homeostasis."

The team estimates some nine million diabetes cases in Chinese adults may be attributed to exposure to outdoor LAN. Unfortunately, the number could increase as people continue to move closer to cities and away from the countryside.

"Our findings contribute to the growing evidence that LAN is detrimental to health and point to outdoor LAN as a potential novel risk factor for diabetes," the researchers wrote.

This is another example of the detrimental impacts associated with the global light pollution issue, which has, among its other impacts, affected animals' habits and migration patterns, and even disrupted their ability to observe the skies.