GLC
Head Chef
They didn't study men. Thought that was interesting. I
They reported on women because they were using the dataset created by the Women's Health Initiative, a set of clinical trials running since 1991 "to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer."
The dataset is a collection of a large number of variable of several different types, which helps analyze results. When you have that kind of data, the studies are actually reports of statistical studies, rather than a single researcher carrying out a study to collect data independently. Because of the number of variable recorded in the Initiative, statistical analysis is very complicated but potentially very informative and reliable, because it considers so many factors that might otherwise be suspected of being involved in the effects. The analysis tells you which variable actually correlate to the effects. In other words, you don't necessarily have to guess correctly and then do a study to test your guess. The numbers tell you what's significant, even if you didn't suspect that outcome. That's very powerful. It can tell you things you literally would never have guessed.