Widespread exposure to outdoor lights could represent a big risk factor for breast cancer
We all love outdoor lighting or security lights as people commonly refer to them. They illuminate surroundings at night and make it possible to spot danger and avert it whenever possible.
It is for this reason that people also like living in areas with sufficient outdoor light at night – be it in the form of street lights lining roads or those illuminating house compounds at night.
Even though these lights generally make people feel safe at night, they could also be exposing many women to adverse health consequences.
A study published in the Environmental Health Perspectives journal showed that widespread exposure to outdoor lights during night-time could represent a big risk factor for breast cancer.
The research, conducted in the United States by the Harvard School of Medicine scientists looked at data from over 100,000 women from 1989 t0 2013 to examine possible links between the light and the disease.
Women exposed to the highest levels of outdoor light at night (those in the top five) had an estimated 14 per cent increased risk of breast cancer during the study period, compared with those that had low exposure (bottom five).
As levels of outdoor light at night increased, so did breast cancer rates. This association was found only among women who were pre-menopausal and those who were current or past smokers.
In addition, the link was stronger among women who worked night shifts, suggesting that exposure to light at night and night shift work contribute jointly to breast cancer risk.
Previous studies have shown that exposure to light at night may lead to decreased levels of a hormone known as melatonin which can disrupt the circadian rhythms - our internal “clocks” that govern sleepiness and alertness – thus leading to increased breast cancer risk.
Selecting bedrooms located far from outdoor light rays at night, as well as draping windows with appropriate curtains that shield bedrooms from such artificial external light could help address the challenge by minimising exposure to outdoor light at night.