Pluses and minuses for women taking HRT
Hormone replacement therapy can be a godsend for those suffering from menopause symptoms. But what are the potential side effects?
Hormone replacement therapy (HRT) can have a hugely beneficial effect on unpleasant menopause symptoms, reducing hot flushes, night sweats and mood swings for many of the one million UK women who take it.
But there are fears about the therapy's side effects, with the latest research suggesting HRT - which usually involves the replacement of oestrogen and sometimes progesterone - could be associated with an increased risk of hearing loss in postmenopausal women.
Past studies have claimed HRT increases the risk of breast cancer, although more recent reviews have shown the association was exaggerated.
Then there's cardiovascular disease; some studies say HRT is protective, others say it increases the risks.
Confused? Here's an outline of current thinking on some of the benefits and risks of HRT.
DOES HRT INCREASE THE RISK OF BREAST CANCER?
There was a sharp decline in the number of menopausal women taking HRT following a 2002 study by the US Women's Health Initiative (WHI) that claimed there was an increased risk of breast cancer with the use of oestrogen plus progesterone HRT.
However, a recent review of the evidence has highlighted serious errors in the WHI report, and Dr Heather Currie, chair of the British Menopause Society (BMS), stresses the study didn't show any statistically significant increased risk.
Current evidence shows the risks are small and, for most, outweighed by benefits, including symptom control and improved urogenital, bone and cardiovascular health.
DOES HRT INCREASE THE RISK OF HEART DISEASE?
Despite numerous studies, the effect of HRT on heart disease is unclear. The WHI study found HRT increased the risk of heart disease in healthy postmenopausal women, yet 2012 Danish research found women receiving HRT soon after menopause had a significantly reduced risk of mortality, heart failure or heart attack.
The National Institute for Health and Care Excellence (NICE) says HRT doesn't increase cardiovascular risk when started in women aged under 60, and it doesn't affect the risk of dying from cardiovascular disease.
Yet the British Menopause Society says the ELITE trial has shown starting HRT early is beneficial.
DOES HRT CAUSE HEARING LOSS?
Studies have found that while menopause may increase the risk of hearing loss, possibly because of reduced oestrogen levels, postmenopausal HRT might slow hearing decline by replacing oestrogen. Current US research has suggested postmenopausal HRT may be associated with a higher risk of hearing loss.
But Dr Currie warns that the research relied on women's self-reported hearing loss and doesn't prove HRT causes it.
DOES HRT INCREASE THE RISK OF OVARIAN CANCER?
A 2015 Oxford University analysis of 52 studies found HRT causes a small increase in the risk of ovarian cancer, with one extra case for every 1,000 women taking HRT for five years from the age of 50.
Conversely, The Institute of Cancer Research found women with the most common type of ovarian cancer can safely take HRT, and it can improve their survival chances.
DOES HRT PREVENT OSTEOPOROSIS?
The major underlying cause of osteoporosis is the loss of bone resulting from oestrogen deficiency. Several international medical organisations have stated HRT is effective for preventing osteoporosis-related fractures in at-risk women before the age of 60, or within 10 years after menopause.
DOES HRT INCREASE THE RISK OF BLOOD CLOTS AND STROKES?
A 2015 Cochrane review of existing research confirmed HRT increases the risk of strokes and blood clots, such as deep vein thrombosis. But Dr Currie points out that the risks are affected by the route of HRT used, with transdermal oestrogen showing no increased risk of blood clot, compared with women not taking HRT.