Kelly Bach does all the right things to limit her risk of breast cancer. She exercises, gets plenty of sleep, eats a healthy diet and gets regular checkups. But one possible risk remains: Bach works the graveyard shift.

Three years ago, Hutchinson Center investigators announced findings that suggested women who work at night may stand a greater chance of developing breast cancer than those who work during the day.

Bach, an emergency-room nurse at Seattle's Children's Hospital and Regional Medical Center, doesn't consider those findings threatening enough to rethink her work schedule. However, when she saw a flyer for a follow-up study, she decided to join. "Since I fit the criteria, there was no reason not to," Bach said.

The Hutchinson Center study is examining whether there is a connection between the night shift and decreased melatonin/increased estrogen production. Decreased melatonin production, which can result from disruptions in the sleep/wake cycle and exposure to light at night, prompts the ovaries to make extra estrogen — a known hormonal promoter of breast cancer.

The study requires women to track their menstrual cycle, provide urine samples, complete forms and provide optional blood or saliva samples. The total time commitment is four to six hours, and participants will receive $120-$150 when the study is completed.

Study recruitment continues for both day- and night-shift workers between 20 and 45 years old who work in a Seattle-area hospital or laboratory. Participants must have regular menstrual periods, not take hormonal contraceptives (i.e. the pill or Norplant) and not have been pregnant or nursing in the last year.

Bach urges other women like her to volunteer for the study: "It's easy, and it could end up helping a lot of women someday."

For more information, call (206) 667-5704 (call collect if long distance). All information collected for the study will be kept strictly confidential.

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