Quotes of the Day

The graveyard shift has always been a lonely one to work, but new data suggest that it may be an unhealthy one as well. According to the latest results from the continuing Nurses' Health Study, which surveyed more than 78,500 women, those who worked overnight shifts at least three times a month for 15 years were 35% more likely to develop colon cancer than those who worked only days. Authors of the study, published last week in the Journal of the National Cancer Institute, think the increased risk may be linked to lowered levels of melatonin, which usually reaches peak production in the body in the middle of the night; nighttime exposure to light can dramatically reduce that production. The hormone is believed to have anticancer properties, but researchers say more study is needed before a link can be confirmed.

• Sora Song