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The table below summarizes the available evidence on the risks and benefits of hormone therapy. Included are all randomized trials and meta-analyses looking at disease incidence or mortality. Inclusion of observational trials was dependent on size: case-control studies with 500 or more cases of the disease and cohort studies with at least 2,000 women are included here.

The year noted is when the study results were published. The name following the title of the study is the last name of the first author on the publication.

E = estrogen; P = progestin

Year	Study	Study Type	Participants	Hormones	Results	Other Notes
1985	Framingham Heart Study, Wilson	Cohort	1,234	E	Increases risk 100%	Majority of women used estrogen
1993	Finucane	Cohort	1,910	E	Decreases risk of fatal stroke 63%
1999	Grodstein (A)	Cohort	9,236	E, E + P	No significant difference in risk	Same result for E vs. E + P
2000	Nurses' Health Study, Grodstein	Cohort	70,533	E, E + P	35% increased risk with E alone and 63% with E + P	20 years follow-up
2001	Women's Estrogen for Stroke Trial (WEST), Viscoli	Randomized	664	E	Increases risk of fatal stroke 190% during first 6 months	Participants had recently had ischemic stroke or transient ischemic attack
2001	Heart and Estrogen/progestin Replacement Study (HERS), Simon	Randomized	2,763	E + P	No significant effect on risk among women with coronary heart disease	4.1 years follow-up
2002	Women's Health Initiative	Randomized	16,608	E + P	Increases risk 41%	Average follow-up 5.2 years