The Women's Health Initiative HRT Study (2002)

The 2002 Women's Health Initiative study rocked global medicine by concluding that hormone replacement therapy increased breast cancer risk by 26% and heart attack risk by 29%, leading millions of women to abruptly abandon HRT. However, subsequent re-analysis revealed these risks applied primarily to women over 65 starting therapy more than 20 years post-menopause, not the typical younger menopausal woman. Experts estimate that up to 50,000 premature deaths occurred from untreated menopausal symptoms due to the study's overblown warnings. This overcorrection makes the HRT panic more consequential than the saturated fat debate sparked by the Seven Countries Study.