Age at menarche was based exclusively on self-report. Previous reports suggest that there is generally moderate agreement between age at menarche reported in adolescence and later reported by middle-aged women.36-38 Classifying women into three categories corresponding to early, typical (12-13 years), and late menarche has been reported to improve validity.37 When our data were categorized in this way, results were largely unchanged (results not shown) except for associations that were specific to very early or very late menarche.
