Wednesday February 18 2015
Hot flushes are a common symptom
"Menopause lasts 'up to 14 years'," the Daily Mail reports, with The Daily Telegraph reporting a similar figure – but according to The Guardian, it's "12 years".
All three headlines are prompted by a new US study, which does suggest that, at least in some women, symptoms such as hot flushes can persist for more than a decade.
Menopausal symptoms such as hot flushes and night sweats are collectively known as vasomotor symptoms (VMS), as they are all caused by constrictions and dilations to blood vessels. These can lead to a sudden increase in blood flow, which can then cause hot flushes and excessive sweating.
The study found that on average, women who had frequent VMS did so for more than seven years, with symptoms continuing for over four years after their last menstrual period.
It should be noted that the study focused on a specific group of menopausal women who reported frequent VMS (for six days or more in the previous two weeks). It is not clear if this group is representative of all women going through the menopause.
VMS can usually be successfully controlled using hormone replacement therapy (HRT). HRT does carry a very small risk of triggering hormonal cancers such as breast cancer, and, as we discussed earlier this month, ovarian cancer.
But these risks should be balanced against the benefits HRT can bring to quality of life. There are also self-help techniques you can use to cope better with VMS. Your GP can provide more information about treatment options.
Where did the story come from?
The study was carried out by researchers from several academic centres in the US, and was funded by the US National Institutes of Health, the Department of Health and Human Services, the National Institute on Aging, the National Institute of Nursing Research, and the Office of Research on Women's Health.
One of the authors has financial ties with, and has acted in an advisory capacity to, a number of pharmaceutical companies.
The study was published in the peer-reviewed Journal of the American Medical Association (JAMA) Internal Medicine.
It is unclear why The Daily Telegraph and the Daily Mail reported that the menopause "lasts up to 14 years" and The Guardian decided "symptoms lasted up to 12 years", but all three headlines are potentially misleading.
The study found the average time frequent menopausal symptoms lasted was 7.4 years. Only a very small number of women had symptoms lasting more than a decade.
What kind of research was this?
This was an observational study looking at how long women going through the menopause experience hot flushes and night sweats. These are called vasomotor symptoms, and are caused by the decline in production of the female hormone oestrogen, which in turn can affect blood flow.
The authors also wanted to find out how long frequent symptoms persist after the final menstrual period and identify the risk factors for longer duration of symptoms.
They say vasomotor symptoms (VMS) can significantly affect quality of life and are experienced by up to 80% of menopausal women. These symptoms are also one of the chief menopause-related problems US women seek medical treatment for. Yet there are few robust estimates as to how long VMS lasts.
What did the research involve?
Between 1995 and 1997, researchers recruited 3,302 women for a large multi-ethnic, multiracial US study of the menopause.
The women had to be aged between 42 and 52 years, have an intact uterus and at least one ovary, report a menstrual cycle in the three months before they were screened, and not be pregnant or breastfeeding, or using oral contraceptives or HRT.
Of the initial 3,302 participants, 1,853 were excluded: 330 because they had surgery to remove their womb and ovaries, 583 because they began HRT, and 940 who did not report frequent VMS. The researchers analysed 1,449 women to find out how long they had menopausal symptoms overall.
Women were assessed at the start and followed up with annual visits for between 12.7 and 17.2 years. They were asked at each visit about their lifestyle, psychosocial factors, physical and psychological symptoms, and their medical, reproductive and menstrual history.
The women filled in a questionnaire at each visit about the frequency of hot flushes and night sweats in the previous two weeks.
These were recorded as occurring:
- not at all
- 1-5 days
- 6-8 days
- 9-13 days
- every day
Frequent VMS was defined as occurring at least six days in the previous two weeks.
From the women's self-report of their bleeding patterns during each preceding year, the researchers also assessed whether women were premenopausal, peri-menopausal (near the menopause), or postmenopausal.
Of the 1,449 women, 881 were assessed for how long VMS symptoms lasted after the final menstrual period. Researchers excluded 406 because their final menstrual period could not be dated, 132 who had no frequent symptoms after their final menstrual period, and 30 who began HRT before the first post-final menstrual period report of VMS.
The researchers looked at the total duration of frequent VMS, and the duration of frequent VMS after the final menstrual period. They also assessed the influence of potential confounders, such as:
- sociodemographic factors such as age, race, marital status and education
- psychosocial factors such as attitude towards menopause, anxiety and stress
They analysed the duration of VMS using standard statistical methods.
What were the basic results?
The researchers found that in women with frequent hot flushes and night sweats:
- the average duration of symptoms was 7.4 years
- among 881 women who experienced an observable final menstrual period, the average duration of symptoms afterwards was 4.5 years
- women who were premenopausal or early peri-menopausal when they first reported frequent VMS experienced these symptoms for the longest time overall (on average, for more than 11.8 years) and after the final menstrual period (on average for 9.4 years)
- women who were postmenopausal at the onset of symptoms had the shortest total duration of symptoms (on average, 3.4 years)
- compared with women of other racial or ethnic groups, African-American women reported the longest total duration of symptoms (on average, 10.1 years)
- women of a younger age, lower educational level, greater perceived stress and symptom sensitivity, and higher depressive symptoms and anxiety when they first reported symptoms were more likely to experience symptoms for a longer time period
How did the researchers interpret the results?
The researchers say frequent vasomotor symptoms (VMS) lasted more than seven years during the menopausal transition for more than half of the women, and persisted for 4.5 years after the final menstrual period.
Longer-lasting VMS was associated with being premenopausal and having greater "negative affective factors" in women when they first experienced symptoms.
Healthcare professionals should advise women to expect that frequent symptoms of hot flushes and night sweats could last more than seven years, and they may last longer for African-American women.
This is an interesting study with a long follow-up period. It suggests the length of time women have hot flushes for may be underestimated.
However, it was carried out on US women and the results may not be generalisable to other populations.
That aside, unlike many other studies of its type, it did make an effort to include a range of ethnicities, including Chinese, Hispanic and African-American women.
The study relied on women self-reporting their symptoms only once each year, which may affect its reliability.
It also only looked at women who reported getting frequent vasomotor symptoms (at least six days in the previous two weeks). As a group, this sample may not be representative of menopausal women overall and may be more vulnerable to a longer duration of symptoms.
It is interesting that women who reported more anxiety about menopause also reported a greater duration of VMS.
The menopause is a perfectly natural event, and there are many ways women can learn to cope with its effects.
If symptoms are making you miserable, it’s worth talking to your GP. HRT is often effective, but if you are unable or unwilling to take it, alternatives to HRT are available.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.