“Bright Light Accelerates Ageing in Mice”
by Rebecca Boyle
Nature, July 14, 2016
We’ve corresponded in the past, but I have yet to work with you and the other editors at Nature, and I’m hoping this new pitch will spark your interest! I’m writing with a pitch about a paper appearing next week in Current Biology, about the negative consequences of artificial light at night. I have been covering this topic for two years and I think I’m well suited to writing about this for Nature News. Here’s the pitch:
Working during an artificially lit night has detrimental effects on health, but fixing them may be as simple as shutting off the lights. A new study in mice is the first to definitively link artificial lighting with negative health effects, and it suggests turning off light at night may be as important to health as diet and exercise.
Johanna Meijer of Leiden University Medical Center in the Netherlands kept mice in a brightly lit environment around the clock for six months, and measured what happened to several health parameters. The central circadian pacemaker, the brain’s suprachiasmatic nuclei, went out of whack; its normal rhythms were off by 70 percent. The animals’ bones started to deteriorate, and they experienced inflammation at levels typically seen during a serious infection. But returning the mice to a standard cycle of light and darkness erased those symptoms in just two weeks.
Previous research has hinted at light-related health problems in animals and in humans. There is evidence linking nighttime light exposure to obesity, metabolic syndrome, depression and hormonal cancers in people. Individuals exposed to light at night are known to sleep less, and what sleep they do get is lower quality. But this study is the first to show a definitive causal link between artificial light exposure and wellness. It is a crucial step forward for the growing group of biologists studying the effects of light on health.
What’s more, this work comes on the heels of two other major warnings about the prevalence of artificial light. Two weeks ago, an American Medical Association policy statement called for more studies on the connection between light at night and cancer. And earlier in June, a newly
constructed atlas of artificial light pollution showed that 99 percent of people in North America and Europe are exposed to light at night. Taken together, this research suggests most humans — and animals — on Earth are increasingly paying a price for living in unnatural lighting conditions.
I’m sending links to two relevant clips below. I am also sending a PDF of the paper, which is embargoed until July 13. I would love to write this for Nature — please let me know if you’re interested!