Cessation if hormone replacement therapy after reports of adverse findings from randomized controlled trials: Evidence from a British birth cohort

Objectives. We examined the cessation of hormone replacement therapy (HRT) among British women, by educational level, social class, and cardiovascular risk factors, at the time of publicity about 2 clinical trials of HRT that were halted after adverse findings. Methods. A total of 1387 women aged 57 years reported their monthly HRT use between January 2002 and February 2003. A succession of regression-based time-series models were fitted to detect changes in the proportion of HRT users stratified by education level, social class, hypertension, and obesity. Results. The overall percentage of HRT users declined from 31% in January 2002 to less than 26% by February 2003. Changes in trends of HRT use were first detected in June 2002 (for women with advanced secondary educational qualification or higher) and in July 2002 (for all other groups). The rate of decline was greatest for women with no formal educational qualifications, from the manual social class, or who were hypertensive or obese. Conclusions. These decreases coincided with the announced cessation of a large US clinical trial of HRT. This publicity may have had a differential influence on the immediate decline in HRT use by various groups of British women.