单选

Women who live in areas with higher levels of outdoor light at night may be at
higher risk for breast cancer， according to a study from Harvard T.H. Chan
School Of Public Health. The link was stronger among women who worked night
shifts.
Previous studies have suggested that exposure to light at night may lead to
decreased levels of the homone melatonin ， which can disrupt circadian
rhythms—our internal ’clocks’ that govern sleepiness and alertness—and， in turn，
lead to increased breast cancer risk.
The new study， the most comprehensive to date to examine possible links between
outdoor light at night and breast cancer， looked at data from nearly 110，000
women enrolled in the Nurses’ Health Study II from 1989-2013. The researchers
linked data from satellite images of Earth taken at night time to residential

addresses for each study participant， and also considered the influence of night shift work. The study also factored in detailed information on a variety of
health and socioeconomic factors among participants. Women exposed to the highest levels of outdoor light at night—those in the top
fift— had an estimated 14% increased risk of breast cancer during the study period， as compared with women in the bottom fifth of exposure， the researchers
found. As levels of outdoor light at night increased， so did breast cancer rates.
However， the association between outdoor light at night and breast cancer was
found only among women who were premenopausal 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
jointly to breast cancer risk. What can we learn from the first paragraph？
A.Women who live with higher levels of outdoor light may be at higher risk for cancer.
B.Men who live with higher levels of outdoor light may be at higher risk for cancer.
C.Women who worked night shifts may be at higher risk for breast cancer.
D.Men who worked night shifts may be at higher risk for breast cancer.

试题出自试卷《2017年安徽省直公共基础二真题》

参考答案