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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	Increased risk 50%	8 years of follow-up
1987	Lipid Research Clinics Program Follow-up Study, Bush	Cohort	2270	E	Decreased risk 63%	Average follow-up 8.5 years
1993	Rosenberg	Case-control	858 cases, 858 controls	E	No significant difference in risk
1996	Nurses' Health Study, Grodstein (A)	Cohort	59,337	E, E + P	E alone decreases risk 40%; E + P decreases risk 39%	Up to 16 years follow-up
1997	Heckbert	Case-control	850 cases, 1,974 controls	E, E + P	8.2 years of hormone use decreases risk 45%	Risk decreased with duration of use; little difference between E and E + P
1997	Hemminki	Meta-analysis of randomized trials	22 studies, 4124 women	E, E+P	No statistically significant effect on risk of cardiovascular events	No distinction between E and E + P
1998	Heart and Estrogen/progestin Replacement Study (HERS), Hulley	Randomized	2,763	E + P	No effect over 4 years; 52% increased risk in the first year	Average follow-up 4.8 years; trial participants had prior history of cardiovascular disease
1998	Sourander	Cohort	7,944	E	Current use decreases risk 79%; no significant difference in former users	8 years of follow-up
1999	Grodstein (B)	Cohort	9,236	E, E + P	Decreases risk 25%	Results similar for E alone and E + P
2000	Varas-Lorenzo	Case-control	1,013 cases, 5,000 controls	E, E + P	Current use of E alone for > 1 year decreases risk 48%; current use of E + P for > 1 year decreases risk 21%
2000	Nurses' Health Study, Grodstein	Cohort	70,533	E, E + P	Hormone use decreases risk 39%	Participants had no prior history of cardiovascular disease; no clear difference in risk between E alone and E + P
2001	Nurses' Health Study, Grodstein	Cohort	2,489	E, E + P	Short-term use (<1 year) increases risk 25%; longer-term use decreases risk 62%	Average follow-up 6.9 years; participants had prior history of cardiovascular disease; no difference between E and E + P
2001	Shlipak	Cohort	114,724	E, E + P	Among women with myocardial infarction, hormone use reduced risk of mortality 35%	No distinction between E and E + P; all participants had myocardial infarction
2002	Heart and Estrogen/progestin Replacement Study II (HERS), Grady	Randomized	2,321	E + P	No overall difference in risk over 6.8 years follow-up	2.7 year extension of HERS with subset of participants from original study; 6.8 years total follow-up; trial participants had prior history of cardiovascular disease
2002	Women's Health Initiative	Randomized	16,608	E + P	Increases risk 29%	5.2 years of follow-up