A study discovered a significant relation between how exposure to outdoor artificial light at night (LAN) boosts diabetes risks. It also revealed that the said variable had been linked with problematic blood glucose control.
According to SciTechDaily, the research estimates that more than 9 million diabetes cases among Chinese adults may be attributed to exposure to LAN.
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Is LAN Really a Risk Factor?
Dr. Xu Yu and other colleagues from the Shanghai Institute of Endocrine and Metabolic Diseases conducted the study published in Diabetologia.
It highlights how the rampant nature of exposure to LAN is a risk factor for the condition. This is especially so given how urban light pollution has become more intense, affecting not only those from big urban areas but also from rural and suburban terrains that are distant from the light source.
The researchers note how even if more than 80% of the global population is exposed to light pollution during the evening, this has not been a subject of study for scientists until more recently.
Because the day-night cycle of the earth spans 24 hours, most organisms, including mammals, have a circadian timing system that adapts to the natural flow of dark and light episodes. SciTechDaily notes how light pollution has significantly changed the circadian rhythm among birds, insects, and other animals. This results in biodiversity loss and premature passing away.
Other than this, artificial LAN has also been seen to be a probable culprit behind the dysregulation of the metabolism. It may do so by changing food intake timing.
In fact, rats exposed to the said LAN were seen to develop glucose intolerance. They also exhibited higher blood glucose levels and insulin.
SciTechDaily notes how a different study saw that mice exposed to nocturnal dim and minimally bright white light for four weeks had higher body mass and lower tolerance to glucose. This was compared to animals in a completely dark environment, even if their energy consumption and expense were roughly the same.
Artificial LAN was classified from lowest levels to highest. These degrees were categorized into five corresponding quintiles, which range of groups comprising 20%, from highest to lowest). The median of the strength of light in the highest quintile is 69 times stronger than that of the lowest.
Through the study, the researchers discovered the highest LAN exposure quintile was linked to a comparative 28% boost in diabetes prevalence compared to the lowest quintile. Also, chronic exposure to residential and outdoor LAN was linked to blood sugar levels, diabetes prevalence, and insulin resistance. It was also inversely related to beta cell function, even after adjusting for different diabetes risk factors.
On average, for a group of 42 people from regions classified under the highest quintile, there is a diabetes case that would not have surfaced if the said individuals lived in the lowest-quintile areas.
Such findings contribute to growing evidence that suggests that LAN is not good for health. The researchers conclude that it is necessary to conduct a further study about the direct gauging of LAN exposure on an individual scale. This is important to see if the relationship between LAN exposure and diabetes is causal.
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