The Age Incidence of the Menarche in Copenhagen¹

A halt in the secular trend towards earlier menarche in Denmark

“…The inhabitants of the region, some 30 miles north of Copenhagen, reside in small provincial towns and villages. It has been shown previously that there are no geographical differences with respect to menarche in Denmark (2). In comparison with the girls of the 1966 investigation, born between 1948 and 1956 (shortly after World War II), the living conditions of the girls in the two later studies had improved with respect to, for example, health services, hygiene, and nutrition; but the effect of these improvements on the results could not be assessed.…”

Decrease in Menarcheal Age From 1966 to 1983 in Denmark

“…1). A negligible difference in menarcheal age has been found previously between permanent residents of Copenhagen and new arrivals from the provinces (2). Socio-economic characteristics were not considered.…”

The reliability of recalled estimates of menarcheal age in a sample of older women

“…The intraclass correlation coefficient is 0.81, which indicates reasonably high reliability. (Bojlen et al, 1954;Aw and Tye 1970;Cravioto et al, 1987;Harlow and Linet, 1989;Marshall, 1978). It has been noted that subjects might not accurately remember such data, particularly if they are older.…”

“…In the case of recalled menarcheal age, such bias would occur when a subject mistakenly thinks that she experienced her first menstruation at an incorrect a e. Therefore, studies of menarnot have to be abandone , as long as it can be established that such recollections are reliable. Bojlen et al (1954) concluded that the mean age at menarche obtained with recalled information is inaccurate relative to that obtained with the status quo method, Damon et al (1969) and Roberts et al (1986) concluded that mean menarcheal ages obtained with either technique are not significantly different. The accuracy of recalled menarcheal a e has also been paring recorded and reported menarcheal ages.…”