Saturday, June 03, 2006

France Menarche

"This study compares all calculable means of a new 1974 sample of
3,355 French women ages 17 to 21 with earlier available results, which
indicates a decrease in age at menarche in France and at the same time
a decrease in variance since the last centruy. Plotting all samples
available, the results of equations of linear regression indicate a
decreasing age in France at the rate of -.175 years/decade. ...
Although the rate in France of -.175 seems slower than reported, in
general, .3 years/decade, it is noted that the mean age in France in
the middle of the last century, reported to be 16 or 17, was less than
ages reported in Northern Europe. "

Ducros, A. The trend toward earlier menarche in France. Journal of
Human Evolution. 1981;10(8):623-25.

Evolution of age at menarche and at onset of regular cycling in a large cohort of French women F. Clavel-Chapelon,1 the E3N-EPIC group

Human Reproduction, Vol. 17, No. 1, 228-232, January 2002

BACKGROUND: Early exposure to ovarian hormones is considered to increase breast cancer incidence. The age at which the ovaries become functional is thus important. METHODS: We explored the evolution of age at first menstruation and at onset of regular cycling in 86 031 women participating in the E3N-EPIC cohort study, part of the European Prospective Investigation into Cancer. RESULTS: We observed an increase in mean age at menarche among women born between 1925 and 1930, followed by a steady decrease in the youngest birth cohorts. In contrast, age at onset of regular cycling increased gradually from 1925 onwards. There was thus a steady increase in the interval between age at menarche and at onset of regular cycling, mainly due to an increase in the percentage of women in whom regular cycling started at least 5 years after menarche (from 9.0% among women born in 1925–1929 to 20.8% in those born in 1945–1950). The increase in the interval between menarche and onset of regular cycling was even greater among women with a late menarche. CONCLUSIONS: This increase might be due to a change in dietary intake and/or physical exercise aimed at achieving the slim silhouette desired by the younger generations.

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