The risk of acute myocardial infarction after oestrogen and oestrogen-progestogen replacement.
OBJECTIVE
To determine the relative risk of developing a first acute myocardial infarction after treatment with oestrogens alone or oestrogen-progestogen combinations.


METHODS
Prospective cohort study utilizing a prescription-based and record linkage system for a follow-up period from 1977 to 1983. Average individual observation time was 5.8 years.


METHODS
The entire female population of the Uppsala Health Care Region (1.4 million inhabitants), one-sixth of the total Swedish population.


METHODS
23,174 women aged 35 years and older, identified from pharmacy records as having been prescribed non-contraceptive oestrogens during 1977-1980.


RESULTS
Admissions to hospitals for first acute myocardial infarctions.


RESULTS
Overall, 227 cases of a first acute myocardial infarction were observed as against 281:1 expected, RR = 0.81 (95% confidence limits 0.71 to 0.92). Women who were younger than 60 years at entry into the study and prescribed oestradiol compounds (1-2 mg) or conjugated oestrogens (0.625-1.25 mg) showed a significant 30% reduction of the relative risk (RR = 0.69, 0.54 to 0.86). Those prescribed a combined oestradiol-levonorgestrel brand also demonstrated a significantly lowered relative risk (RR = 0.53, 0.30 to 0.87). The risk estimates were near unity during the first year of follow-up but decreased during subsequent years. Exposure to the weak oestrogen oestriol did not alter the risk.


CONCLUSIONS
Hormonal replacement therapy with oestrogens alone, and maybe also when cyclically combined with progestogens, can reduce the risk of acute myocardial infarction.
Falkeborn
M
M
Department of Geriatrics, University Hospital, Sweden.
Persson
I
I
Adami
H O
HO
Bergström
R
R
Eaker
E
E
Lithell
H
H
Mohsen
R
R
Naessén
T
T
D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D004338:Drug Combinations; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects; D005260:Female; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000139:chemically induced*; D011372:Progestins / Q000009:adverse effects; D011446:Prospective Studies; D012307:Risk Factors; D013548:Sweden
D004338:Drug Combinations; D004967:Estrogens; D011372:Progestins