Study: Hot flashes usually persist for years
Science now has an answer for midlife women wondering how long their menopausal heat waves can persist.
The answer: a long time. The typical duration of frequent hot flashes and night sweats is seven years, and for some women, symptoms persist for a dozen years or more, says a study published Monday in JAMA Internal Medicine.
That's much longer than the six months to two years long thought typical. It is also longer than the time limits many doctors put on treating the symptoms with hormones.
The findings suggest a need for better, longer-lasting treatments, and they also should reassure some women, says lead researcher Nancy Avis, a professor of public health sciences at Wake Forest Baptist Medical Center in Winston-Salem, N.C.
"There's a lot of variability," Avis says. "If you experience symptoms for a long period of time, that doesn't mean there's anything wrong."
Avis and colleagues followed 3,302 midlife women for up to 17 years, including the years just before and just after their menstrual periods ended.
Hot flashes and night sweats can start at any point in that transition. A hot flash is a sudden, intense feeling of warmth, often accompanied by sweating and followed by chills. A night sweat is similar and often disrupts sleep.
Previous research showed that about 80% of U.S. women have at least some hot flashes. The cause is unclear, but it is thought that hormonal changes disrupt the body's thermostat.
The new research focuses on the 1,449 women in the study who reported frequent overheating — on at least six days in two weeks — at any annual checkup. It leaves out nearly 1,000 women who never reported frequent symptoms and others who took hormones or had hysterectomies.
Among those who had frequent episodes, the median duration was 7.4 years, meaning half had symptoms longer and half had them for less time. Some were still having hot flashes after 13 years.
The median was 10.1 years for African-American women, 8.9 years for Hispanic women, 6.5 years for non-Hispanic white women, 5.4 years for women of Chinese descent and 4.8 years for women of Japanese descent.
The reasons for the racial and ethnic differences, seen in several studies, are unknown, Avis says. Differences in genes, diet, childbearing histories and other factors could be at work, she says.
Symptoms persisted longer if they started before a woman's last period. They also lasted longer if a woman was stressed, depressed or anxious before they began.
The relationship between hot flashes and emotional distress clearly goes both ways, says JoAnn Manson, chief of preventive medicine at Brigham and Women's Hospital in Boston.
"Certainly if you have these symptoms several times a day and you are not sleeping well, that is going to lead to stress," says Manson, who co-wrote an editorial accompanying the study.
There are treatments. Hormone therapy with low doses of estrogen, sometimes combined with progesterone, is the most effective, but it is associated with risks of breast cancer, stroke and blood clots that increase with time and age. For healthy post-menopausal women with moderate to severe symptoms, many doctors still recommend it for up to four or five years, Manson says.
Women still having periods can take low-dose birth control pills, both to control hot flashes and to prevent pregnancy, she says.
Brisdelle, a low-dose version of the antidepressant Paxil, also is approved for hot flash treatment by the Food and Drug Administration.
Women looking to over-the-counter supplements are out of luck: none have panned out in rigorous studies, Manson and Avis say.
But lifestyle changes can help. The National Institute on Aging has these tips:
• Avoid any hot flash triggers (such as spicy food, alcohol and caffeine).
• Sleep in a cool room.
• Dress in layers that can be removed easily.
• Have a cold drink of water when you fee a hot flash coming on.
• Don't smoke.