Why do some women have an earlier menopause?

Most of the variation between individual women is down to genes in the same way that balding in men depends on their genetic inheritance. There has been no link established between the age of menopause and the age at which women start menstruating. There also appears to be no link between menopausal age and number of children women have. However there are some factors which do affect the onset of menopause, such as diet, work and exercise. Surveys show that women in the ‘first world’ affluent countries generally have later menopause than in 'third world’ poorer countries