Hormone Therapy and its Role in Cardiovascular Health

What is Cardiovascular Disease?

Cardiovascular disease (CVD) is an umbrella term for a variety of different diseases that affect the heart and blood vessels of the body. (1) It commonly includes heart failure, high blood pressure, high cholesterol, coronary heart disease, cardiomyopathy, congenital heart disease, peripheral vascular disease and stroke. (1)

Types of Cardiovascular disease can either be acute such as angina, stroke or heart attack and are mainly contributed by blockages of certain arteries, or it could be progressive caused by stress, excessive alcohol, trauma or chronic hypertension that has not been adequately treated. Smoking and poor dietary and lifestyle habits contributes to the compromised health of the cardiovascular system. (2)

Some signs and symptoms of cardiovascular disease include:

• High blood pressure
• Pain or discomfort in the middle of the chest
• Pain that can been associated with breathlessness and sweating
• Radiating pain in the shoulders
• Pressure or tightness in the chest
• Radiating pain in the neck, jaw and arms
• High pulse rate
• Nausea, dizziness, fatigue and sweating that is associated with chest pain, high pulse rate or high blood pressure (3)

There are known risk factors that correlate to the development of Cardiovascular disease and these include:

• Physical inactivity- Increases blood pressure, cholesterol levels and weight gain. (4)
• Smoking- Smoking damages the lining of the blood cells, can increase fat deposits in the arteries and potentially increases clotting. (4)
• Diet high in saturated fat and sodium- Increases blood pressure, fat deposits in arteries and cholesterol levels (4)
• High alcohol intake- Can damage the heart muscle and increase risk of stroke (4)
• High cholesterol– Can increase fat deposits in arteries increasing the risk of blockages, heart attack and stroke (4)
• Obesity- May lead to an elevation in blood pressure and increase fatty deposits in arteries (4)
• Diabetes- People with diabetes are 2-4 times more likely to develop CVD and this is the leading cause of death in diabetics. (4)
• Family history of Cardiovascular disease- Having a first-degree male relative who has suffered a heart attack prior to the age of 55 or, a first degree female relative who has suffered one before the age of 65, increases your risk of developing heart disease (4)

The Statistics

Unfortunately, Cardiovascular disease is the leading cause of death in Australia. (1) It has been estimated that 1.2 million Australians over the age of 18 have experienced a condition related to the heart or vascular system. (5) Approximately 2.6 million Australians reported having high blood pressure and 430,000 have reported having a heart attack at some point in their life. (1)

The risk of developing CVD increases with age with 1 in 4 of those aged 75 and over having a heart attack or some sort of vascular disease. (5)

The role of hormones in Cardiovascular Health

The main female sex hormone involved in regulating blood pressure is of course, oestrogen. How oestrogen influences blood pressure is still being widely studied, however in both animal and human models oestrogen has been shown to induce vasodilation (dilate blood vessels) by increasing the amount of nitric oxide being produced and as a result, can aid in the prevention of vasoconstriction (narrowing of the arteries) which is correlated with an elevation in blood pressure. (6)

Many longitudinal studies have been conducted and have found a 4-fold increase in blood pressure during the onset of menopause. Because menopause is associated with a natural decline in oestrogen levels, it is this decline that has been in part, associated with elevation in blood pressure during this life stage. Support for this comes from observations that during the menstrual cycle, blood pressure tends to be lower during the luteal phase (when oestrogen levels are at their highest) than during the follicular phase (where oestrogen levels are at their lowest) (6)

We know that natural production of oestrogen has a positive correlation with blood pressure however, conjugated, synthetic oestrogens have been shown the opposite. A study by Wren et al. shows synthetic preparations of oestrogen have been shown to increase blood pressure in women who would have otherwise, had healthy blood pressure. 4 months after ceasing the synthetic preparations, blood pressure normalised. (7)

In a different randomised, controlled, cross over trial, although it only studied 30 menopausal women with mild hypertension, it indicated some promising results. (8) The women used 100mg of transdermal (applied to skin) oestradiol and over 24 hours their blood pressure had reduced, particularly of a morning and evening. These studies need to be conducted over a larger scale to accurately determine how oestrogen truly benefits blood pressure. (8)

Much of the limited research conducted is indicating that transdermal Oestrogen reduced blood pressure, whereas oral treatment of Oestrogen did not alter blood pressure. This is a positive outcome as transdermal Oestrogen is proving to be protective against high blood pressure. (9, 11)

In another study, Oestrogen was found to stimulate certain growth factors and prostaglandins which prove to be protective against cardiovascular disease and high blood pressure. (10,11)

Although larger studies are certainly required, the beneficial role Oestrogen has on the cardiovascular system cannot be discounted. Please speak to our doctors today to determine your suitability for therapy.

1. https://www1.health.gov.au/internet/main/publishing.nsf/Content/chronic-cardio#ris
2. https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)
3. https://www1.health.gov.au/internet/main/publishing.nsf/Content/chronic-cardio#ris
4. https://www.world-heart-federation.org/resources/risk-factors/
5. https://www.aihw.gov.au/reports/heart-stroke-vascular-disease/cardiovascular-health-compendium/contents/how-many-australians-have-cardiovascular-disease
6. Dubey R, Oparil S, Imthurn B, Jackson E. Sex hormones and hypertension. Cardio Res 2002;53: 688-708
7. Wren BG, Routledge DA. Blood pressure changes. Oestrogens in climacteric women.Med J Aust 1981;2:528–531.
8. Mercuro G, Zoncu S, Piano D et al. Estradiol- 17B reduces blood pressure and restores the normal amplitude of the circadian blood pressure rhythm in postmenopausal hypertension. Am J Hypertesn 1998;11:909-13
9. Akkad A, Halligan A, Abrams K, al-Azzawi F. Differing responses in blood pressure over 24 hours in normotensive women receiving oral or transdermal oestrogen replacement therapy. Obstet Gynecol. 1997. 89(1): 97-103
10. Zacharieva S et al. Effect of transdermal oestrogen therapy on some vasoactive humoral factors and 24h ambulatory blood pressure in normotensive postmenopausal women. Climacteric. 2002. 5(3): 293-9
11. Cagnacci A, Rovati L, Zanni A, Malmusi S, Facchinetti F, Volpe A. Physiological doses of Estradiol decreased nocturnal blood pressure in normotensive postmenopausal women. Am J Physiol. 1999. 276(4). 1355-60