Nature, Science

Light Pollution Linked to Immune Problems in Hamster Pups

Light pollution--including exposures to light at night from our tablets, phones, and TVs--can have more serious effects than previously imagined.
Light pollution–including exposures to light at night from our tablets, phones, and TVs–can have more serious effects than previously imagined. Photo: Shutterstock

According to a study by researchers at The Ohio State University, disruptions in sleep schedules are not only bad for the health of animals and people, but they can have effects which are passed on to offspring. What’s more, these problems can also be caused not just by interrupting sleep schedules, but by unnaturally light night.

To do the study, researchers used nocturnal Siberian hamsters. They exposed one group of hamsters of both sexes to a standard light day/dark night cycle, and one group to dim light at night, for nine weeks. They then mated the hamsters in four groups—mothers or fathers with dim-light exposure, both parents with exposure to light at night, and both parents with standard light exposure. After the hamsters mated, the entire group lived under standard light conditions.

The researchers found that dim light exposure had a definite influence on the offspring. Fathers and mothers seemed to pass along genetic instructions that impaired immune response and decreased endocrine activity. But it’s especially important to note that the negative changes were traced to both parents.

“These weren’t problems that developed in utero. They came from the sperm and egg,” said senior study author Randy Nelson, “It’s much more common to see epigenetic effects from the mothers, but we saw changes passed on from the fathers as well.”

While this certainly adds to the ongoing discussions of how screens are affecting us as we use them late at night, it has some other implications too. Light pollution is not a problem that has been taken very seriously in the past, despite the fact that previous research has proven that it has negative effects on animals. It has been known to interrupt animal sleep and activity patterns, and this new research has shown some specific, and negative, consequences of light pollution.

But it’s not just for animals that we should be concerned. Humans are making continued use of screens at night, often in otherwise dark rooms, which seems to be having some negative effects on our bodies. Studies have shown that it interrupts sleep and strains our eyes, but the OSU study shows that it could actually affect how genes are passed on to children.

“I think people are beginning to accept that light pollution is serious pollution and it has health consequences that are pretty pronounced—an increase in cancers, depression, cardiovascular disease, diabetes, and anxiety disorders,” Nelson said. “We should be concerned about the increasing exposures to light at night from our tablets and phones and TVs.”