Establishing the risk related to hormone replacement therapy and cardiovascular disease in women

Hormone replacement therapy (HRT) has a profound impact on the cardiovascular system in postmenopausal women, achieved through its effects on metabolic risk factors for coronary heart disease (CHD) and on arterial function. Observational studies have consistently shown an association between postmenopausal HRT use and a reduced incidence of CHD. However, the largest randomised trial initially reported no overall benefit on CHD risk. Subsequent analyses and follow-up of the study have demonstrated a significant benefit for CHD risk in healthy women initiating oestrogen therapy soon after the onset of menopause. This benefit of early initiation of HRT has been confirmed in more recent trials and in meta-analyses. The dose and type of hormones at initiation of therapy appears crucial to obtaining CHD benefit.