The association between early menopause and risk of ischaemic heart disease: influence of Hormone Therapy.
Randomised clinical trials find no protection against development of ischaemic heart disease by use of Hormone Therapy (HT) after the age of 50 years. Observational studies suggest that early menopause is a risk factor for ischaemic heart disease. Yet, a clinical very relevant question is whether HT reduces this risk associated with early menopause.


OBJECTIVE
To analyse whether early menopause based on various causes are independent risk factors for ischaemic heart disease, and to investigate whether the risks are modified by use of HT.


METHODS
In a prospective cohort study questionnaires were mailed to Danish female nurses above 44 years of age in 1993. Information on menopause, use of HT and lifestyle was obtained. In total 19,898 (86%) nurses fulfilled the questionnaire, among them 10.533 were postmenopausal with definable menopausal age, free of previous ischaemic heart disease, stroke or cancer. Through individual linkage to national register incident cases of ischaemic heart disease were identified until end of 1998.


RESULTS
Menopause below both age 40 and 45 was associated with an increased risk of ischaemic heart disease, seeming most pronounced for women who had an early ovariectomy but also among spontaneous menopausal women. Generally HT did not reduce the risk except for the early-ovariectomised women, where no increased risk of ischaemic heart disease for HT users was found.


CONCLUSIONS
We found an increased risk of ischaemic heart disease associated with early removal of the ovaries that might be reduced with HT. The present study need confirmation from other studies but suggests that early ovariectomised women could benefit from HT.
Løkkegaard
E
E
The Danish Nurse Cohort Study, Center for Alcohol Research, National Institute of Public Health, Denmark. loekkegaard@dadlnet.dk
Jovanovic
Z
Z
Heitmann
B L
BL
Keiding
N
N
Ottesen
B
B
Pedersen
A T
AT
D000328:Adult; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D008019:Life Style; D008594:Menopause, Premature / Q000502:physiology*; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology* / Q000503:physiopathology; D010052:Ovariectomy; D016016:Proportional Hazards Models; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D011795:Surveys and Questionnaires