There is growing evidence for the harmful effects of “circadian disruptions” - or unnatural nighttime light exposure - that have become the norm ever since the first person flipped an electrical light switch to turn on a lamp. The newest study on these effects suggests that these interruptions can have damaging effects on not just one organism, but their offspring as well.
It is not the first time circadian disruptions have been linked to health problems; previous studies found associations with cancer and diabetes. The present study, from Ohio State University, looked at hamster babies born from parents who did not receive a normal amount of daylight and darkness right before mating. They found that their offspring were born with “weakened immune systems and impaired endocrine activity.”
Past studies have shown that animals exposed to light at night experience changes in endocrine and immune function, and but apparently their misfortune is also inherited by their offspring. What exactly is being passed down between these two generations? Epigenetic changes?
To say for sure, Ohio State researchers conducted a series of experiments with male and female hamsters exposed to light at night before they mated. The offspring of this experimental group were “reared in standard light day/dark night conditions.”
The results confirmed that there is a genetic connection between parents and offspring concerning the continued negative effects of circadian disruption. "These weren't problems that developed in utero. They came from the sperm and the egg," explained Randy Nelson, senior study author from Ohio State.
Nelson and his team found little difference between fathers and mothers as far as the genetic material inherited by their offspring that impacted immune and endocrine function, but more studies must be done to confirm the individual role each parent plays in this hereditary condition.
"Now, we're seeing for the first time in these hamsters that it's possible this damage isn't just being done to the affected individuals, but to their offspring as well," Nelson said.
What is the connection to humans? Consider light pollution, Nelson says. While increasing the amount of time one can stay awake and be productive at night via electrical technology may not be the first issue that comes to mind as far as increasing one’s risk of preventable disease, the present study suggests that it may be more of a problem than people realize.
"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.
The present study was published in the journal Scientific Reports.
For more on the effects of light pollution:
Source: Ohio State University