Hormone replacement therapy Cardioprotective effect is genuine

Hormone replacement therapyCardioprotective effect is genuine EDrroR,-Ward F M Posthuma and colleagues suggest that preventive hormone replacement therapy is unjustified because the observed pro- tection from stroke and ischaemic heart disease could be accounted for by selection of healthy women in uncontrolled studies.'Their own argu- ments and citations, however, are also biased.Central to their thesis is the apparent correlation of the degree of reduction of risk with lowered incidence of cancer across these studies.They reason that this proves that "healthy cohorts" were recruited rather than that cardiovascular events were genuinely prevented by hormone replacement therapy.Women seeking hormone replacement therapy, however, tend to have higher socioeconomic status.This in turn is associated with a raised incidence of the commonest malignancy in women, which tends to bias the studies in the opposite direction.There is also limited support for the authors' sweeping statement that "cancers are if anything increased" by oestrogens.For combined oestrogen and progestagen replacement to physiological concentrations, as commonly used in Britain, the evidence is non-existent.