This week, Drs.

The role of hormones in the development and progression of lung cancer in women has generated much interest. Unfortunately, a lot of the data to date has been observational, which doesn't establish a "cause and effect" relationship. The Nurses Health Study (more on this below) is a good example: a large cohort of women was observed over time. The women completed questionaires on all sorts of exposures (diet, hormone replacement therapy, tobacco, etc), and they were followed over time.