The average age at which a woman reaches menopause in the United States is approximately 51 years, reports the journal Obstetrics and Gynecology Clinics of North America. In many developing nations the age is lower than that, but it occurs later in Japan.
The reasons for international variation in average age of menopause are not completely understood as of 2015, says WebMD. Interestingly, how many children a woman has, how young she was at the onset of menstruation, and whether or not she has used hormonal birth control are not significant indicators.
There are multiple known factors that correlate with the age at which menopause occurs, including genetics, smoking, location and socioeconomic status. Women of lower socioeconomic status and women who live at high altitudes tend to experience menopause earlier than those who are wealthier, according to an article in the journal Menopause, both within the United States and internationally.
The strongest indicator of when a woman expects to experience menopause is the age at which her mother did, says WebMD, although it is worth noting that other factors matter. A woman is sometimes more affected by the factors she experienced as a young woman than those she experiences closer to menopausal age, according to LiveScience.
Women in Paraguay are particularly young at this transition, with an average age of 43.8 years, reports Menopause. The relatively high age of onset among Japanese women perhaps relates to consuming a diet high in vegetables and relatively low in fat, states the American Journal of Epidemiology.