Hormone replacement therapy: real concerns and false alarms.

From 2002 to 2008, reports from the Women's Health Initiative (WHI) claimed that hormone replacement therapy (HRT) significantly increased the risks of breast cancer development, cardiac events, Alzheimer disease, and stroke. These claims alarmed the public and health professionals alike, causing an almost immediate and sharp decline in the numbers of women receiving HRT. However, the actual data in the published WHI articles reveal that the findings reported in press releases and interviews of the principal investigators were often distorted, oversimplified, or wrong. This review highlights the history of research on HRT, including a timeline of studies that have or have not found a link between HRT and breast cancer; discusses how to distinguish important, robust findings from those that are trivial; closely examines the WHI findings on HRT and breast cancer, most of which are weak or statistically insignificant; reviews the current thinking about possible links of HRT with cardiovascular disease and cognitive functioning; and reports research on the benefits of HRT, notably relief of menopausal symptoms, that affect a woman's quality of life. On these complicated matters, physicians and the public must be cautious about accepting "findings by press release" in determining whether to prescribe or take HRT.