According to a recent American study, being exposed to strong artificial light outside at night increases the risk of thyroid cancer by 55%.
55% higher risk
Street lights and illuminated shop windows at night disrupt the internal clock, and increase the risk of developing thyroid cancer by 55%. This is revealed by a study conducted for nearly 13 years by researchers at the University of Texas, in the United States, published on February 8 in the journal of the American Cancer Society. To reach this conclusion, a team of scientists followed for 12.8 years 464,371 American adults whom they had recruited in 1995 and 1996. At the time, they were between 50 and 71 years old. They then estimated the nighttime artificial light levels at the participants using satellite imagery. Data correlated with that of the National Cancer Registry to identify diagnoses of thyroid cancer up to 2011. As a result, 856 cases of thyroid cancer were diagnosed, 384 in men and 472 in women. The researchers point out that the higher level of light is associated with a 55% higher risk of developing thyroid cancer. Women had more localized forms of cancer while men were more affected by more advanced stages of the disease.
Further research needs to be done
“As an observational study, our study is not designed to establish a causal link. Therefore, we do not know if higher levels of outside light at night lead to a high risk of thyroid cancer. ; however, given the well-established evidence that supports the role of night light exposure and disruption of the circadian rhythm, we hope that our study will motivate researchers to further examine the relationship between light at night and cancer, and other diseases, says lead author Dr Xiao. Recently, efforts have been made in some cities to reduce light pollution, and we believe future studies should assess whether and to what extent these efforts have an impact on human health, “he continued. Further research must therefore be carried out to confirm these results.
