Exposure to outdoor artificial lights at night can increase diabetes risk by 28%

Exposure to outdoor artificial light at night (LAN) can increase a person’s risk of developing diabetes by 28 per cent, according to a new study. Researchers in China have found that LAN is associated with an increased risk of diabetes and impaired blood glucose control, with more than 9m cases of the disease in Chinese adults attributed to LAN exposure. Streetlights, cars, and well-lit storefronts were found to have a detrimental effect on health, with scientists claiming that the findings could have implications for late-night shift workers.’Despite over 80 per cent of the world’s population being exposed to light pollution at night, this problem has gained limited attention from scientists until recent years,’ the study authors said.The new study, which has been published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]), used data from the China Noncommunicable Disease Surveillance Study; a representative sample of the general population in China taken in 2010 across 162 sites across the country in which nearly 100,000 people participated.Body weight and height measurements were taken, along with blood samples to obtain levels of both fasting and after-meal glucose, as well as glycated haemoglobin (HbA1c). This is a form of glucose found in red blood cells which acts as a moving average of blood sugar over the previous eight to 12 weeks.Scientists found that those with the highest proportion of LAN exposure were associated with a 28 per cent in the prevalence of diabetes.Researchers noted that the omnipresence of outdoor artificial light means that the scale of such exposure is ‘vast’, with more than 99 per cent of those in the US and Europe living under light-polluted skies. The authors conclude that ‘further studies involving the direct measurement of individual exposure to LAN are needed to confirm whether its relationship with diabetes is a causal one’.The Earth’s 24-hour cycle has led to most organisms, including mammals, having a 24-hour circadian rhythm affecting physical, mental and behavioural changes which instinctively adapt to the natural sequence of light and dark. The disruption of circadian rhythms has been linked to decreased cognitive function, disrupted sleep, mood disorders and lower levels of happiness.