Andrew Shelling
This important study published in the leading journal, the British Medical Journal, provides an update on the risks of Menopause Hormone Therapy (MHT) and the risk of Thrombotic Disease (conditions in which an abnormal blood clot forms within a blood vessel or the heart and impedes blood flow).
It is a very large nation wide case control research study undertaken in Denmark, and specifically looking at associations between current use of menopausal hormone therapy and development of venous thromboembolism, ischaemic stroke, and myocardial infarction.
The results are largely supportive of previous studies and show that the current use of any oral menopausal hormone therapy was associated with an increased venous thromboembolism risk, whereas ischaemic stroke and myocardial infarction risk was only increased with oral high dose therapy used for more than one year.
Transdermal therapy was not associated with increased thrombotic rates regardless of regimen, active ingredients, dosage, and duration of use. This would suggest that the route of administration of MHT is important. Oral formulations that involve metabolism in the liver that are associated with clotting proteins that increase risk, whereas transdermal oestrogen largely avoids this effect and consequently has a lower thrombotic risk.
This study shows that although MHT is associated with a small increase in thrombotic risk, the absolute risk is low in most women and is outweighed by the benefits of menopause symptom relief. Risk assessment should be individualised, considering other health factors such as obesity, smoking, previous disease, age, and route of administration. Transdermal oestrogen generally carries a lower thrombotic risk than oral therapy.