UBC Reports | Vol. 50 | No. 4| Apr. 1, 2004

Plant-based Hormone Offers New Hope for Hot Flushes

UBC study tests safer replacement for estrogen

By Hilary Thomson

Imagine that your heart starts pounding, your skin temperature suddenly spikes and you break out in a sweat that wakes you up at night and forces you to fling off clothing during the day.

Now imagine these embarrassing and sometimes debilitating personal heat waves persisting for years.

This is the world of night sweats and hot flushes -- the characteristic mid-life change experienced by about 75 per cent of women in perimenopause and the early years after menopause. In the first study of its kind, UBC researchers are testing a manufactured hormone that might provide safe and effective relief for tens of thousands of women troubled by these symptoms.

Christine Hitchcock, a researcher at the Centre for Menstrual Cycle and Ovulation Research (CeMCOR), is testing the effectiveness of Prometrium®, the commercial name for a plant-based manufactured hormone that is chemically identical to the progesterone produced by the body. Approximately 60 women will use a placebo or Prometrium® for four months to determine if the drug can control hot flushes as well as improve blood vessel function and help prevent heart attack.

Betty-anne Dempsey is a participant in the trial. The 51-year-old had been on hormone replacement therapy (HRT) for hot flushes that were leaving her sleep-deprived. She stopped using HRT because of a family history of heart disease and had tried herbal remedies without success.

“I got involved with the study because I want some relief but I also want to make sure I’m well,” she says. “Participating in the study gives me more insight into my own health.”

Until recently, hot flushes were treated with estrogen. Many women stopped estrogen therapy, however, after the results of the Women’s Health Initiative Study announced in July 2002 that estrogen with low dose progestin (a synthetic form of progesterone) increased risk of pulmonary embolism, heart attack, stroke and breast cancer.

“The importance of safe and effective therapy becomes even more clear as the dust settles from the trials of menopausal hormone therapy. Early studies suggested that progestins were effective in hot flush control but this is the first study to test natural oral progesterone for these symptoms,” says principal investigator Jerilyn C. Prior, a professor of endocrinology who is scientific director of CeMCOR, a part of UBC’s Dept. of Medicine and the Vancouver Coastal Health Research Institute (VCHRI).

In addition to learning about the drug’s effect on hot flushes, Hitchcock and Prior will examine its effects on cholesterol, blood pressure, blood sugar and weight gain. They are particularly interested in blood vessel function and will use a forearm blood flow test that can predict risk of cardiovascular disease. Participants will also keep a daily menopause diary to record the incidence and severity of flushes and sweats as well as other experiences such as insomnia, depression and fluid retention.

“We want to be able to give women a choice and a more targeted therapy for hot flushes. Also, this study will provide important information about the effects of progesterone alone on cardiovascular health,” says Hitchcock.

Scientists do not know the exact mechanism of hot flushes. They believe that flushes originate in the hypothalamus -- the area of the brain that integrates stressors. Somehow, the body registers that its core temperature is too hot. It produces the flushes to get hot blood away from the core and move it to the skin’s surface to cool down.

The average age of onset for hot flushes is 48. They can be triggered by warm environments, hot or spicy food, alcohol, caffeine or stress. An individual flush usually lasts from a few seconds to 30 minutes or an hour and may happen a few times a day or once a week. The phenomenon can continue for four to nine years surrounding the time of the last menstrual cycle.
Men who have been castrated because of testicular cancer or those receiving hormone therapy for prostate cancer may also experience flushes and sweats.

For more information on hot flushes, visit the CeMCOR website at www.cemcor.ubc.ca. To learn more about the trial, click on ‘get involved’. The study has been initiated by researchers and is not sponsored by a drug company.

CeMCOR distributes information directly to women about changes through the life cycle, from adolescence to menopause.

VCHRI is a joint venture between UBC and Vancouver Coastal Health that promotes development of new researchers and research activity.