Street lamps can increase your risk of CANCER: People living near artificial neon lights are more than 55% more likely to be diagnosed with thyroid cancer.
- Researchers looked for cases of cancer in a survey among adults aged 50 to 71 years
- They then looked at levels of light pollution at night near the volunteer home
- There has been a marked increase in incidents of thyroid cancer in mild areas
- The team may be dealing with lower melatonin levels due to light
Living outside in an area with high levels of artificial light can increase the chance of thyroid cancer – with neon lights increasing the risk by 55 percent, study shows.
Researchers from the University of Texas Health Science Center have been looking for a link between people who develop thyroid cancer and levels of artificial outdoor light.
They looked at data from a group of 464,371 participants who were followed for about 13 years as part of the NIH-AARP diet and health study – and then analyzed satellite images to estimate the levels of light in the areas where the people involved lived at the study.
They found that those in areas with the highest levels of pollution during the night had a 55 percent higher risk of developing thyroid cancer than those in low-light areas.
They believe one reason for the link is that light at night suppresses melatonin, a modulator of estrogen activity – which can have an antitumor effect.
Living outside in an area with high artificial light can increase the chance of thyroid cancer – with neon lights increasing the risk by 55%.
Over the past century, night photos – especially in cities – have changed dramatically due to the rapid growth of electric light, study authors said.
Studies have also reported an association between higher satellite-measured levels of night light and increased risk of breast cancer.
Since some breast cancers may share a common link with thyroid cancer, lead author Qian Xiao and colleagues decided to look for a link between night light and later development of thyroid cancer.
They used the NIH-AARP Diet and Health Study – with information on hundreds of thousands of people aged 50 to 71 – recorded in 1995 and 1996.
Xiao then looks at satellite images of each of their homes to determine if those living in high-light areas are more likely to develop thyroid cancer.
The team then searched the database of cancer registries to identify diagnoses of thyroid cancer through 2011 and found 856 cases among the 464,371 volunteers.
“Compared to the lowest quintile light at night, the highest quintile is associated with a 55 percent higher risk of developing thyroid cancer,” Xiao said.
“The association was mainly driven by the most common form of thyroid cancer, called papillary thyroid cancer, and it was stronger in women than in men,” he found.
In women, the association was stronger for localized cancer, without spreading to other parts of the body, while the association was stronger for more advanced stages of cancer.
The association appears to be similar for different tumor sizes and for participants with different demographic characteristics and body mass index.
The researchers noted that additional studies are needed to confirm their findings.
If confirmed, it is important to understand the mechanisms underlying the link between night light and thyroid cancer, Xiao said.
The scientists noted that light at night suppresses melatonin, a modulator of estrogen activity that can have important antitumor effects.
Light at night can also lead to disruption of the internal clock (or circadian rhythms) of the body, which is a risk factor for various types of cancer.
They found that those in areas with the highest levels of pollution during the night had a 55 percent higher risk of developing thyroid cancer than those in low-lying areas.
“As an observational study, our study was not designed to determine causality,” Xiao said, adding “we do not know whether higher levels of outdoor light at night lead to an increased risk of thyroid cancer.”
“Given the established evidence supporting the role of night exposure and circadian disruption, however, we hope that our research will motivate researchers to further investigate the link between night light and cancer,” said Dr. Xiao said.
“Recently, efforts have been made in some cities to reduce light pollution, and we believe that future studies should evaluate whether and to what extent such efforts affect human health.”
The findings were published in the journal Cancer.