From an online article:
Researchers analyzed serum total testosterone and sex hormone-binding globulin levels from a cohort of 208,677 men aged 40 to 69 years participating in the population-based, prospective cohort UK Biobank study from 2006 to 2010. Demographic and medication information...
KEY POINTS
*The average age of menopause is 51.5 years in the United States. Twenty percent of women have essentially no symptoms, and 20% of women have severe symptoms. One percent of women are menopausal by age 40, and 5% by age 45.
*Classic symptoms include hot flashes (usually early on)...