How has hormone replacement therapy (HRT) use changed in the ten years since the Women’s Health Initiative (WHI) published alarming findings that estrogen plus progestin increased breast cancer and heart disease risk? A recent study published in Obstetrics and Gynecology and led by University of Vermont Assistant Professor of Surgery Brian Sprague, Ph.D., sought to answer this question, as well as measure the percentage of postmenopausal women in the U.S. currently taking HRT.

To determine the long-term trends of HRT use, Sprague and colleagues used data from National Health and Nutrition Examination Survey (NHANES) surveys – a nationally representative sample – conducted between 1999 and 2010. The group generated prevalence estimates for the entire country and found that postmenopausal HRT use in the U.S. has declined continuously to low levels across a wide variety of patient subgroups.

“From 1999 to 2002, one in five women older than age 40 was a current user of oral postmenopausal hormones,” explains Sprague. “By 2009–2010, the prevalence was fewer than one in 20; only 1.7 percent of women aged 40 and older report current use of estrogen plus progestin formulations.”

The sharpest decline – almost 50 percent – occurred during the first two years following the halt of the estrogen plus progestin arm of WHI study, when overall HRT use went from 22.4 percent in 1999-2000 to 11.9 percent in 2003-04. While the earliest observed decline was found predominantly in non-Hispanic whites, Sprague’s study showed that the use of both estrogen alone and estrogen plus progestin continued to decrease between 2005 and 2010 and was observed in women of all ages, races or ethnicities, education, income groups, and those with and without hysterectomy. 

“There are still differences in the prevalence of hormone use according to socioeconomic indicators such as income and race,” says Sprague, who works in UVM’s Office of Health Promotion Research. “However, the differences in use according to these characteristics are much smaller than they used to be.”

According to Sprague, criticisms and concerns about the WHI trial have continued to crop up over the past decade. In surveys on the subject, physicians have reported being skeptical about the results and how they apply to their patients.

“Our findings suggest that these concerns about the Women’s Health Initiative have not led to a rebound in the use of postmenopausal hormones,” says Sprague. He and his coauthors note that, since 2001-2002, “the prevalence of hormone use among women aged 40 and older had declined by . . . 79 percent in 2009–2010.”

The researchers recommend continued monitoring of treatments for menopausal symptoms in order to keep track of the therapies’ impact on women’s health.