Coronary Heart Disease (CHD) is well understood to be one of the major causes of mortality worldwide. Risk factors are generally equal for men and women, except for one main consideration: Menopause.
In an inspiring session at COGI, Prof. John Stevenson explained that women who experience earlier menopause are the most at risk. Indeed, those who experience menopause below the age of 40 are at 2x greater risk of CHD than women who are above 45 years. So, what can be done?
An opportunity for HRT?
Prof. Stevenson explained that HRT could provide an answer. Research indicates that estrogen has a clear biological effect on the cardiovascular system, demonstrating beneficial effects on some of the key risk factors of CHD. These include dyslipidaemia, insulin resistance and arterial endothelial function.  However, dealing with the problem is not that easy.
The disparagement of HRT in the 2000 Women’s Health Initiative (WHI) study still fuels debate over the benefit and safety of its use for CHD. In addition, some randomised controlled trials (RCTs) have suggested only negligible effects.
While Prof. Stevenson accepted that there is a lack of definitive evidence supporting HRT as a prevention for postmenopausal CHD, he demonstrated that there is a growing number of epidemiological and observational studies supporting its use. One recent Cochrane review studying 40,410 women indicated a decrease in CHD risk for those starting HRT treatment within 10 years of menopause. Similarly a separate study suggested that women <60 years treated by HRT experienced a reduced total mortality. Long term safety has also been demonstrated with even the WHI publishing data showing that in women aged 50-59, treatment with HRT provided in a hazard ratio of 0.65 (CI 0.44-0.96).  In older women there was no statistical difference. 
Timing is key
Time is an essential factor to consider. Prof. Stevenson explained that to have a beneficial effect, early intervention is needed. In fact, research supporting the use of the HRT as a primary prevention of CHD in postmenopausal women has demonstrated no benefit if the intervention in older women., However, it was stressed that while there was no benefit for late intervention, there was also no evidence of harm.
There are other considerations to take into account. Benefit may also depend on the type of hormones being administered or the dose of hormones. Prof. Stevenson concluded in stating that HRT should only be used where appropriate and with careful consideration.
 Stevenson JC. HRT and cardiovascular disease. In Lumsden, MA, ed, Best Practice and Research Clinical Obstetrics and Gynaecology, Vol 23. Elsevier 2009:109–120. https://www.sciencedirect.com/science/article/pii/S152169340800148X
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