Most women expect hot flashes as a part of the "change
of life," but more than half start sweating before menopause has actually
begun, according to a survey.
The study and others "indicate that women start having
hot flashes and night sweats, the primary symptoms of the menopause transition,
before they have their final menstrual period, contrary to the perception of
many clinicians", according to Ellen Gold, of the University of
California, Davis School of Medicine.
Previous studies put the number of women with hot flashes at
15 or 20%, but asking specifically who had hot flashes in the past two
weeks may be a better measure of early onset menopause symptoms than the
current study, which asks if they have ever had a hot flash, said
Gold, who was not involved in the study.
The findings, published in the journal Menopause, shouldn't
be a concern for women, but it may change how researchers look at hot flashes,
according to lead author Dr Susan Reed who studies women's mid-life health at
the University of Washington in Seattle. Usually associated with menopause, hot
flashes and night sweats occur when hormone changes cause blood vessels near
the surface of the skin to open rapidly.
Women with regular menstrual cycles should have enough
oestrogen to stave off hot flashes, but they may have to re-evaluate that idea,
Reed told Reuters Health by email. Reed and her co-authors sent questionnaires
to 18 500 women between 45 and 56. About half responded. Of the 1 500 who still
had regular cycles and weren't taking medications such as antibiotics or
hormone replacement, 55% reported having experienced a hot flash or night sweat
at some point in their lives.
More than half of white, black and Native American women
reported the symptoms, compared to 30% or fewer of Asian and Hispanic women. The
study was funded by Otsuka Pharmaceutical Co., Ltd., which is developing
S-Equol, a compound that may mimic oestrogen and could be a potential treatment
for menopausal symptoms.
Many women have hot
flashes but don't find that they disrupt daily life, said Ellen Freeman, of the
University of Pennsylvania Perelman School of Medicine in
Philadelphia."Note that only 22% were 'bothered,'" so more than half
of the women who had experienced a hot flash weren't troubled by it, Freeman
told Reuters Health by email.
Relationship with soy
Though it wasn't their primary aim, the researchers also
looked at how much soy the women reported eating. Soybeans contain weak
oestrogen-like compounds, which are not as strong as oestrogen but have been
linked to reduced fertility and early puberty in women.
Among white women, those with menopausal symptoms seemed
more likely to eat soy regularly, while white women without symptoms were more
likely to never have eaten soy. There was no relationship with soy in the other
However, a recent study found that eating soy doesn't
alleviate hot flashes. "Given the design of the study, it is possible that those
women with hot flashes had increased soy intake to try to manage their hot
flashes -- we don't know which came first," Reed's co-author Katherine
Newton told Reuters Health.