The majority of past clinical studies have shown that women who use estrogen substantially reduce their risk of developing and dying from heart disease. One or two studies demonstrate conflicting evidence, but they are far outnumbered by the positive reports. Results from a 1991 study showed that after 15 years of estrogen replacement, risk of death by CVD was reduced by almost 50 percent and overall deaths were reduced by 40 percent. Some researchers credit this reduction to oral estrogen's ability to maintain HDL and LDL at their healthier, premenopausal levels, through its interaction with proteins in the liver. In the latter case, both oral estrogen and the skin patch would be effective.
Studies are underway to determine which mechanism contributes most to a healthy heart.
Risk factors for heart disease include a strong family history of CVD, high blood pressure, obesity, and smoking. At any time of life, women who smoke are much more likely to develop heart disease or have a stroke than women who do not smoke. But after menopause, a smoker's risk climbs dramatically. When the two are combined, the risk is much higher than either one alone. Smoking also raises your risks for some types of cancer and for chronic lung disease, such as emphysema.