Hormone replacement therapy (HRT) increases the risk of strokes in postmenopausal women, while providing little protection from cardiovascular disease, a review published in the Cochrane Library has found.
The review analysed 40,410 women aged over 60 from around the world in 19 randomised trials. Participants were given either oral hormones such as oestrogen and progestogen. The length of the treatment was between seven months and 10 years, depending on which trial participants were entered in.
The review discovered that the risk of a stroke for women taking oral hormones rose to six per 1000, while the increased risk of venous thromboembolism was eight per 1000 women. The risk of suffering from a pulmonary embolism rose to four per 1000.
The authors commented: 'Our review findings provide strong evidence that treatment with hormone therapy in postmenopausal women overall, for either primary or secondary prevention of cardiovascular disease events, has little if any benefit and causes an increase in the risk of stroke and venous thromboembolic events.
The review also found that those who started hormone therapy less than 10 years after the menopause had lower mortality and coronary heart disease rate compared with those who started treatment more than 10 years after the menopause. It showed evidence that the timing of starting the hormones had little effect on death or coronary heart disease between groups but there was an increased risk of stroke and venous thromboembolism in those who started treatment more than 10 years after the menopause.
Maureen Talbot, senior cardiac nurse at the British Heart Foundation, said: 'HRT is not specifically prescribed to prevent or treat coronary heart disease, but to control symptoms of menopause. This study supports what we already know and indicates a possible increased risk of stroke or formation of a blood clot in some women.'