Heart disease is the leading cause of death for women, but because men have higher rates of heart disease it has long been assumed that estrogen is what creates that difference. Heart disease is more prevalent in post-menopausal women than pre-menopausal women, so this has also helped fuel the myth that estrogen has something to do with heart problems. Actually it is probably just due to the fact that post-menopausal women are older.

There has been a clear relationship established between amounts of natural estrogen and breast cancer, osteoporosis and endometrial cancer. The longer you have natural estrogen in you because of early menstruation, drinking alcohol, or certain medications the greater the risk of breast cancer and the lower risk of osteoporosis. However, no clear relationship has been established between natural estrogen and heart disease.

So what does put a woman at risk for heart disease? A family history of heart disease. Levels of lipids, the most common one is known as cholesterol, are also a factor. High levels of an amino acid called Homocysteine have also been shown to increase risk. (Good news is that can be lowered with vitamin B and folic acid.) High levels of C Reactive Protein produced during periods of inflammation increases heart disease risk and this protein is also increased by estrogen. Other factors that increase the risk for heart disease include personality type, diabetes, smoking, being overweight, having high blood pressure and having blood that clots easily.

In terms of Estrogen therapy and heart disease, this means that even though studies have shown that HRT reduces the risk of heart disease in women, the studies have been more observational in nature. Because the studies are observational they really have not yet answered the question if the issue is that estrogen lowers the instance of heart disease or if the instance of heart disease is lower because women who are healthy tend to be on estrogen in the first place. None of the studies done so far have been random controlled blind studies. All the women were of higher social and economic status, highly educated, thinner, non-smokers and also were more likely to have had a hysterectomy. They were more likely to have insurance coverage, therefore more likely to go to a doctor regularly and have had preventive healthcare, lowering their risk of heart disease anyway.

All in all, the evidence showing that HRT can lower the risk of heart disease is circumstantial and considering the recent studies showing links to Breast Cancer and HRT, it would seem that whatever unproven benefit of HRT does not outweigh the risk of taking it. And the American Heart Association recommends the same thing - women with heart disease should not be given HRT to prevent further occurrence and women already on HRT that have heart disease should only continue to take it if the have an additional reason to take it besides heart disease.

There are additional ways to prevent heart disease besides HRT than you can do, like lifestyle changes and drugs that can lower your cholesterol and blood pressure so if the only reason you are considering HRT is for heart disease, it's probably best to pursue those other options first.