Night light from street lamps and phones can raise risk of diabetes

STREET lights and smartphones can raise the risk of diabetes by more than a quarter, new research has found.

Artificial light at night alters the human body clock, impairing its ability to control blood sugar levels.

Lights that could have a harmful effect are street, car and shopfront lamps as well as the light from smartphones and tablets.

The research was based on almost 100,000 men and women in China who were exposed to artificial light while it was dark outside.

Those exposed the most were 28 per cent more likely to develop diabetes because of the interference the light had on the body’s production of melatonin – the hormone that helps regulate our circadian rhythms.

Evidence is growing that 24/7 lifestyles are wreaking havoc with our health by interfering with production of melatonin. Chronic exposure to residential outdoor artificial light was linked to a rise in glucose levels, insulin resistance and diabetes prevalence.

It was also associated with poorer function of beta cells which control blood sugar by releasing insulin, a hormone stored in the pancreas. Lead author Dr Yu Xu, of Ruijin Hospital,

Shanghai, said: “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 in Diabetologia estimated more than nine million cases of diabetes in Chinese adults can be attributed to it.

The researchers used data from the China noncommunicable disease surveillance study, a representative sample of the general population across 162 sites across the country.

A total of 98,658 participants underwent interviews to collect demographic, medical, household income, lifestyle, education and family history information.

Body weight and height were measured to calculate BMI, and blood samples were taken to obtain levels of both fasting and after-meal glucose.

Dr Xu said the findings “contribute to the growing evidence that light at night is detrimental to health” and “points to outdoor LAN [light at night] as a potential novel risk factor for diabetes”.

More than 99 per cent of people in the US and Europe live under light-polluted skies.

Around five million people in Britain have diabetes with 90 per cent of cases of the type 2 form caused by unhealthy lifestyles.