Objective- We sought to examine whether age at menarche has changed over the past 4 decades by comparing age at menarche by year of diagnosis with type 1 diabetes (T1DM).
Research Design and Methods- This was a cross sectional study of age at menarche in two cohorts: adolescents (ages 11- 24 years, n=228), and adults (ages 19-55 years, n=290, enrolled in the Coronary Artery Calcification in Type 1 Diabetes study).
Results- The adolescent cohort reported a younger age of menarche than the adult women with TIDM (12.69 ± 0.08 years vs. 13.22 ± .12 yrs, mean± SE, P< 0.001). Age at menarche was later in both adolescent girls and adult women with T1DM diagnosed prior to menarche (12.82 ± 1.16 and 13.7 ± 2.23, mean± SE) than for those diagnosed after menarche (12.12 ± 1.25 and 12.65 ± 1.38, mean± SE, P<0.001 for both). Age at menarche was then examined by decade of T1DM diagnosis (1970-79, 1980-89, 1990-99, and 2000-09). Age at menarche significantly declined over the four decades (P=0.0002). However, the delay in menarche among girls diagnosed with T1DM before menarche compared to those diagnosed after menarche was also significant across all decades (P<0.0001), and did not change significantly over time (P=0.41 for interaction of cohort and diagnosis pre-menarche).
Conclusions- Age at menarche has declined over the past 4 decades among girls with T1DM, but a delay in age at menarche among those diagnosed prior to menarche compared to those diagnosed after menarche remains.
- Received May 9, 2010.
- Accepted September 6, 2010.
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