Too Much Light at Night May Raise Odds for Thyroid Cancer
The researchers compared satellite imagery data – to estimate nighttime light levels at each participant’s address – to data from national cancer registries up to 2011.
They found 856 cases of thyroid cancer among the more than 464,000 participants, all of whom were followed for an average of about 13 years. These cases included 384 men and 472 women.
Researchers reported that people who lived in areas of the highest 20% night-light category had a 55% higher risk of developing thyroid cancer, compared to those who lived in the 20% age group. % the lowest. The risk was primarily seen for the most common form of thyroid cancer, called papillary thyroid cancer.
The researchers also found that the association was stronger in women than in men. They found that for women, the association was stronger for localized cancers that had no signs of spreading to other parts of the body.
For men, the association was stronger for more advanced stages of cancer. The association was similar for different tumor sizes and participant demographics, including socio-demographic characteristics and body mass index (weight).
So how could light at night cause thyroid cancer?
According to Xiao’s group, night light suppresses natural melatonin, a modulator of estrogen activity. Too low melatonin activity could help reduce the body’s ability to fight tumors, they said. Light at night can also disrupt the body’s circadian rhythm, which is also a risk factor for cancer, the researchers said.
Dr Shuchie Jaggi is an attending physician in Endocrinology, Diabetes and Metabolism at Northwell Health in Great Neck, NY Reading the results, she said that it is possible that nighttime light affects the thyroid through its effect on hormones, and ” certainly the large sample size of this study is a force that makes these associations more statistically significant. “
Jaggi noted that the study had a flaw: Because it relied on satellite imagery, it could only look at exterior light levels at night, not whether people kept their interior lights on as well.
For his part, Har-El said that this is only “the first study to look into this aspect of advanced technology affecting our way of life, and it is only a study”, therefore, much more research is needed.
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