Hot flashes that are common during and after menopause may last an average of more than 10 years, suggests a new study.
The research, published this month in Obstetrics & Gynaecology, also found that women who start getting hot flashes before menopause or in the early stages of menopause will have them for longer, on average, than women who don't have their first hot flashes until later.
"Hot flashes are pretty common, they're distressing and bothersome to a fair number of women, and they're starting earlier" than previously assumed, Ellen Freeman, the study's lead author from the University of Pennsylvania School of Medicine, said.
Freeman and her colleagues followed a group of about 400 women in their 30's and 40's, starting in 1995. Over the next 13 years, the researchers interviewed participants every year or so, asking them questions about their health, including menopause symptoms.
Only 55 of the women were entirely free of hot flashes during the study. Another 90 said they only had mild flashes, and the rest - 259 women - reported moderate to severe hot flashes in at least one interview.
For women who reported hot flashes, those symptoms lasted an average of 11 and a half years. Moderate to severe hot flashes specifically went on for about 10 years on average.
And they stuck around for longer in women who had their first hot flashes when they were younger and before menopause started. Black women and normal weight women also reported having moderate to severe hot flashes at more of the annual interviews than white women and obese women.
"Everyone recognises that there can be a lot of variation in individual women's experience of menopause," Dr Alison Huang, a women's health researcher at the University of California, San Francisco who has no link to the study, said. "Some women never develop these symptoms at all, while others have symptoms that are very severe or persistent."
The researchers said they don't know why there was so much variation in the timing of women's first hot flashes in relation to menopause in this study. But one thing does seem clear: they can last a long time.
"The assumption has been that (hot flashes) last about four to five years," Rebecca Thurston, who has studied menopause symptoms at the University of Pittsburgh, said.
"Part of the issue has been that we haven't really followed women for long enough or gotten them soon enough" to estimate the duration of hot flashes, added Thurston, who was not involved with the current research.
One thing the new study didn't cover, she said, is how frequently participants had hot flashes. It's possible that while women continue having hot flashes for years, they have fewer each day as they get older, Thurston said.
The findings raise the question of what the best treatments are for hot flashes, Freeman said - given that those treatments might be needed for years on end.
Thurston said that while some women do find ways to cope with their hot flashes, "we need more safe and effective treatments for women that they can use for the long-haul." (Reuters Health/ May 2011)