Individuals frequently exposed to outdoor artificial light at night (LAN) are 28% more likely to develop type 2 diabetes compared to those who are rarely exposed, new research identifies.
Academics from Ruijin Hospital, Shanghai Jiaotong University School of Medicine and the Shanghai Institute of Endocrine and Metabolic Diseases have found an association between poor blood glucose control and frequent exposure to artificial LAN.
Type 2 diabetes is a metabolic condition whereby the body is either resistant to its own insulin, or does not make enough.
Symptoms of type 2 diabetes are identical to prediabetes symptoms and include urinating more than usual, particularly at night, feeling thirsty constantly, and feeling very tired.
Approximately nine million type 2 diabetes cases in China were caused by artificial LAN exposure, the study has reported.
The researchers said: “Despite more than 80% of the world's population being exposed to light pollution at night, this problem has gained limited attention from scientists until recent years.”
Previous studies have found that artificial LAN can trigger other health complications, such as cardiovascular disease and disrupted circadian rhythms.
In addition, prior research has discovered an association between frequent artificial LAN exposure and being obese.
People living in busy cities are more likely to be exposed to artificial LAN, putting them most at risk of developing type 2 diabetes, according to the findings.
During the study, the team of scientists examined the health outcomes of more than 98,000 participants who were questioned on all aspects of their life, including household income, education and medical history.
The participants also underwent physical tests, where they had their BMI calculated and blood samples taken so the researchers could measure their fasting and postprandial serum glucose, as well as glycated haemoglobin (HbA1c).
As part of the study, the adults were exposed to artificial outdoor LAN, with the participants being exposed for different lengths of time.
The researchers found that those regularly exposed to artificial LAN are 28% more at risk of developing diabetes compared to people who are not exposed.
According to the report, more than 80% of the global population live under ‘light-polluted skies’.
“Further studies involving the direct measurement of individual exposure to LAN are needed to confirm whether its relationship with diabetes is a causal one,” said the researchers.
The study has been published in the journal Diabetologia.
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