Epidemiology and the menopause: a global overview.

There are 470 million women aged 50 years and older living in the world today, in other words, older than the average age of natural menopause throughout recorded history. Only 50 years ago, even in developed countries, the average women did not live to be 50 years of age. The result of this increased survival is that more and more women are living for longer and longer periods of time after their menopause. What are the implications of prolonged life after the menopause? Most of the current interest in the menopause is prompted by its possible relation to chronic diseases, most notably reproductive cancers, osteoporosis, and heart disease. All of these conditions are more common in women after the menopause, and two of them are directly influenced by the use of replacement estrogen. Thus, estrogen replacement reduces the risk of osteoporotic fractures by about 50%, and unopposed estrogen doubles or triples the risk of endometrial cancer. The risk of these conditions without treatment differs in different countries and populations, and consequently the benefit of hormone replacement will differ. The largest potential benefit of estrogen replacement therapy is the prevention of heart disease. In countries with a relatively high risk of heart disease, observational studies suggest that estrogen reduces this risk by 50%. In other areas, where heart disease in women is much less common, the use of estrogen to prevent heart disease in otherwise healthy women is inappropriate given the uncertain relation of long-term estrogen therapy to the risk of breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)