The harms of the Women’s Health Intiative
The Women’s Health Initiative (WHI) was an ambitious project conducted by the U.S. National Institutes of Health (NIH) started in 1991 to address the women’s liberation movement’s observation that most important medical studies before then were conducted in white males. The WHI consisted of multiple clinical studies and also observational study arms. The WHI study recruited postmenopausal women in the 50-79 age range and tried to be as inclusive as possible such that nearly half of the studied women were current or past smokers, more than a third had high blood pressure and 70% were overweight or obese.
One of the clinical studies under the WHI was the dietary modification intervention that included almost 50 thousand women, 40% of whom were tried on a low fat diet that reduced dietary fats from the pre-study level of 30% of total intake of calories to 20% for a period of 8 years. This reduction in fats in the diet did cause some reduction in blood fat levels and blood pressure but did not reduce coronary heart disease or stroke.
But the big news of the WHI was the 2002 report that another arm of the study was being discontinued prematurely because there was a signal that hormonal replacement therapy in post menopausal women was causing more breast cancer than placebo. Also there was more heart disease, stroke and dementia from estrogens. This news contradicted widespread belief that estrogen was all good and many women were taking it to treat hot flashes and other symptoms of menopause. Over night most doctors said “whoops” and took those women off estrogens. In 1998, before the splash of this report, 60% of postmenopausal women were taking estrogens. In 2012 only 23% were.
I just read a book called Estrogen Matters (2018 Little, Brown Spark, Hachette Book Group, New York, NY) by Avrum Bluming, MD, an oncologist, and Carol Tavris, PhD, a social psychologist and writer, that convinces me that the WHI abruptly swung the pendulum of using estrogen to treat menopause too far in the other direction and deprived a whole generation of women entering menopause after 2002 from the benefit of estrogen. In reality this may not have been justified by the actual data of this landmark study.
These authors develop a wide ranging review of how evidence in this business is marshalled. The gold standard is a placebo controlled prospective study which is what the WHI was and that should beat any observational studies which is what the evidence for the benefits of taking estrogen after menopause was before the WHI. But it’s complicated there are also many caveats to placebo controlled prospective studies too and sometimes that gold standard can be fatally tarnished.