Epidemiology of the menopause.

Profound changes in birth and mortality rates in this century are resulting in the ageing of the population of Britain and other developed countries. The enormous decline in maternal mortality, in particular, has meant that increasing proportions of women are surviving to the menopause and years of active life beyond it. Women aged 55 years and over now comprise 15% of the population of Britain. The average life expectancy for women in developed countries is around 75 years; approximately 90% of women reach the age of 65 years, and 30% reach 80 years. If the average age of menopause is 50 years, most women will spend approximately one third of their lifetime in postmenopausal life; one in every two women will experience about 30 years of postmenopausal life.