(timeline) Landmarks From Two Decades of Study - NYTimes.com

By THE NEW YORK TIMES

Published: April 9, 2011

1991 National Institutes of Health embarks on a study of menopause hormones after observational data suggest that women who use hormones have lower rates of heart disease.

Related

• The Women’s Health Initiative and the Body Politic (April 10, 2011)

2002 Part of the Women's Health Initiative is stopped after women in the study taking estrogen plus progestin (E+P) show higher rates of heart attack, stroke and breast cancer. Millions of women abandon hormones overnight.
2003 Women taking E+P are not protected from mild memory loss; they are found to be at increased risk for developing dementia.
2004 The second W.H.I. hormone study is stopped one year early because women taking estrogen only show a small increased risk of stroke.
2006 An updated analysis of the estrogen-only trial shows hormone therapy does not increase the risk of breast cancer in postmenopausal women.
2007 Combined data from both hormone trials suggest that timing of therapy may affect risk; hormones may reduce heart disease in women who start therapy closer to menopause.
2009 Women using E+P for more than about five years double their annual risk of breast cancer. That risk is higher than previously thought.
2011 Follow-up of women in the estrogen-only study shows those who took just estrogen had 23 percent fewer breast cancers; younger estrogen users had 46 percent fewer heart attacks.
Sources: Women’s Health Initiative; New York Times reports