Living near street lights may increase women's risk of breast cancer, according to new research.
Scientists say women who often work under artificial light, such as night workers, are more likely to suffer from the disease.
Researchers believe that artificial light disrupts women's normal physiological rhythm, the internal clock of the human body, which disrupts natural biological processes.
Studies have also found that it prevents the secretion of a protective hormone that helps prevent disease.
In the largest study ever, experts at Harvard Medical School found that the incidence of breast cancer increased with the increase of artificial light exposure.
But this association is only found in pre-menopausal women who smoke now or in the past.
Professor Peter James of Harvard Medical School in Boston said: "In modern industrialized society, artificial lighting is almost everywhere.
"Our results suggest that extensive exposure to outdoor light at night may be a new risk factor for breast cancer.
"His team has followed nearly 110,000 participants in the United States for 15 years.
Women in the top five were 14% more likely to develop breast cancer than those in the bottom five.
Professor James said previous studies have shown that it reduces the production of melatonin, a hormone that predicts darkness.
Usually, the level changes during the day, peaks at night and decreases during the day.
Studies have found that women with less melatonin, such as those who work at night or sleep less, have a higher risk of breast cancer.
In the laboratory, melatonin has been shown to slow the growth of tumors.
Professor James added: "Only premenopausal women and current or past smokers will find a link between night outdoor light and breast cancer.
"In addition, women working on night shifts are more closely linked, suggesting that exposure to light during night shifts and night shifts contributes to the risk of breast cancer, possibly through a circadian rhythm disorder mechanism.
The study was published in the Journal Environmental Health Outlook.
An early study by Israeli scientists also found a link between artificial light. -at-
Night and breast cancer incidence in satellite analysis of 180 countries.
Western European countries have the highest level of communication.
The same team also found that men and women living in the brightest-lit towns were also more likely to be obese.
Experiments on mice by Belgian researchers also showed that exposure to light 24 hours a day for five consecutive weeks increased fat by 50 percent.
Several studies have shown that women who work at night-
For example, factory workers, doctors, nurses and police-
Women who work during the day have a higher risk of breast cancer.
Dr. Richard Burkes, of Breast Cancer, said the study needed further research.
In particular, we hope that further research will investigate how night exposure to sunlight and breast cancer risk are further affected by smoking or menopausal status to understand the possible biological mechanisms behind these risk factors.
"At the same time, we encourage any woman concerned about their risk of breast cancer to consider known risks. -
Reduce choices, such as regular physical activity, maintaining a healthy weight, reducing alcohol consumption, before moving to the countryside or sleeping behind the house.
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