This is the seventh part of our series about the menopause based on our booklet “Fast Facts for Patients: Menopause”, which is freely available online. This article shows the benefits as well as risks of hormone replacement therapy.
When considering hormone replacement therapy (HRT), it is important to think about the benefits in terms of helping with symptoms during the menopause transition and the long-term benefits.
HRT protects against osteoporosis and cardiovascular disease (CVD) (depending on individual circumstances), and protects the vaginal and bladder tissues.
If you are under 60 and in good health, the benefits of HRT far outweigh the risks. However, the risks may be higher if you are overweight, smoke or have a family history of certain conditions. These risks need to be taken into account when considering which HRT is best for you.
The Long-Term Benefits of Hormone Replacement Therapy
Oestrogen is important for bone health. Bone density decreases after the menopause, increasing the risk of osteoporosis (thinning of the bones). This in turn increases the risk of fractures (breaks), particularly of the hip, wrist and vertebrae (the bones that make up the spine). Osteoporosis affecting the vertebrae can cause loss of height and back pain.
HRT reduces bone loss and the risk of fractures. A long-term US study of 81,000 postmenopausal women showed that the risk of hip fracture increased by 55% when women stopped taking HRT.
Women under 60 who have risk factors for osteoporosis (for example, fracture or loss of height) or a family history of the condition should consider HRT to reduce the risk of osteoporosis and fractures.
Osteoporosis means thinning of the bones. It particularly affects the wrists, hip and spine.
- Regular weight-bearing exercise is important to keep your bones strong – walking, running or any other form of “impact” exercise.
- It is also important that you have enough calcium and vitamin D in your diet, and exposure to sunlight, as these are also important for bone health.
CVD – which includes stroke and heart attack – is the leading cause of death in women over 50. Heart attack is the most common cause of death in postmenopausal women.
Lack of oestrogen after the menopause is one of several factors that increase the risk of CVD. Others include smoking, obesity, high blood pressure, diabetes and high cholesterol.
Oestrogen (either natural oestrogen before the menopause or the oestrogen in HRT) improves blood lipids (fats): it increases high-density (“good”) cholesterol and decreases low-density (“bad”) cholesterol. This protects against the development of atherosclerosis (a fatty layer in the blood vessels), which is the main cause of CVD.
Starting HRT within 5–6 years of the menopause protects against CVD: it reduces the risk of CVD by 40% and decreases the death rate from CVD. HRT also decreases the risk of stroke if started during the menopause transition.
As long as you start HRT early, you do not need to come off it at age 60, but it may increase the risk of CVD if started after age 60.
The beneficial effects appear to be greater in women who take oestrogen only.
Oestrogen helps to maintain the cartilage that lines the bones in joints and the discs between the vertebrae in the spine.
Cartilage can become thinner after the menopause, increasing the risk of arthritis and causing backache and other joint pain.
The oestrogen in HRT protects the cartilage, decreasing the risk and severity of arthritis. Progestogens seem to neutralise some of this benefit, but the Mirena intrauterine system (IUS) can be used to reduce the amount of progestogen in the bloodstream.
Memory and Brain Function
Long-term use of HRT within the first 5 years of the menopause has been shown to improve memory and reduce the incidence of Alzheimer’s disease.
Other Beneficial Effects of HRT
- Studies have consistently shown a 20% reduction in the incidence of bowel cancer in women who take HRT compared with those who don’t.
- Women using HRT have a lower incidence of stomach cancer.
- Cataracts have been shown to be reduced by 60–80% in women taking HRT.
- Glaucoma (high pressure in the eye) may be less common in women taking HRT.
- Oestrogens seem to protect teeth, possibly by preserving the jaw bone.
The Risks of Hormone Replacement Therapy
Deep vein thrombosis (DVT; blood clots in the leg) is the most significant risk associated with HRT. Pieces of a clot may break off and lodge in a blood vessel in the lungs. This causes a blockage called a pulmonary embolism (PE). Symptoms can include shortness of breath, chest pain when breathing in and coughing up blood.
- About 1% of PEs are fatal. Together, DVT and PE are referred to as venous thromboembolism (VTE).
- The risk of VTE is very low in women under 60.
- The risk increases with age. The risk is also increased by lifestyle factors such as obesity and smoking, and being immobile for a long time (for example, on long flights).
- In a study of 1,000 women who took oestrogen-only HRT for 5 years during their 50s, 2 had DVT.
- This number increases to 5 per 1,000 with combined HRT. However, there is no increased risk if oestrogen is taken as a patch, gel or spray.
- There is also no increased risk of DVT with tibolone, which is sometimes used instead of HRT.
HRT is known to protect against CVD when started early but women who start HRT after 60 have an increased risk of CVD. This is thought to happen because oestrogen dilates (stretches) the blood vessels, causing the fatty lining in the arteries to break off, which may cause a blockage.
If women do start HRT later in life, the lowest possible dose should be used and, ideally, patches, gel or spray rather than tablets.
Stroke is rare in women under 60 but it is the second most common cause of death in older women. The risk may be reduced by using the lowest dose of HRT, ideally applying it with patches, gel or spray rather than taking tablets.
Gall Bladder Disease
HRT has been found to increase the risk of gall bladder disease (gall stones and/or gall bladder inflammation). This risk may continue for some years after HRT is stopped. Using oestrogen via the skin as a patch, gel or spray reduces this risk and is therefore recommended for women who are potentially at risk (for example, if you are overweight).
Please check out the previous and the next post of our series here:
Information based on Fast Facts for Patients: Menopause (Karger, 2021).