Artificial Light At Night Could Increase Risk Of Thyroid Cancer Up To 55 Percent, Research Indicates

New research indicates that living near street lamps could increase the risk of thyroid cancer by 55 percent.

The report, published in the American Cancer Society journal Cancer, used data compiled by researchers who gathered information from the National Institutes of Health and the American Association of Retired Persons, Fox News reported. The team gathered data from 464,371 adults who participated in a 13-year survey observing their diet and health habits. They also studied satellite imagery of where the participants lived, estimating the levels of nighttime light surrounding their homes.

The research found 856 cases of thyroid cancer among the participants. Of those, 384 were men and 472 were women. The team divided the number of cases into five sub-groups based on the levels of artificial luminescence at their homes and concluded that the highest of those groups was linked to a 55 percent increase in papillary thyroid cancer, which is the most common type of the disease, the article continued.

Although women were more likely to develop the illness, research indicated that it was more likely to spread in men, who were also more likely to suffer from metastatic thyroid cancer, a more advanced form of the illness.

The report theorized artificial luminescence at night impedes the release of melatonin in the evening hours. Melatonin also regulates the female hormone estrogen, which might be a critical component for preventing tumor growth. In addition, the report noted that disruptions in circadian rhythm might also be a risk factor for other types of cancer.

The researchers noted that their findings could not definitively conclude that night luminescence causes the illness, but that their findings were a cause for additional research.

"As an observational study, our study is not designed to establish causality. Therefore, we don't know if higher levels of outdoor light at night lead to an elevated risk for thyroid cancer; however, given the well-established evidence supporting a role of light exposure at night and circadian disruption, we hope our study will motivate scientists to further examine the relationship between light at night and cancer, and other diseases," Dr. Qian Xiao, one of the scientists, said in a statement.

"Recently, there have been efforts in some cities to reduce light pollution, and we believe future studies should evaluate if and to what degree such efforts impact human health."
The study was conducted by researchers at the University of Texas in Houston after another analysis from 2017 revealed a link between breast cancer and luminescence at nighttime, according to Fox.