Secular trends in age at menarche in Norwegians born from 1840 to 2008.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies/surveys
PubMed 41334879 · doi:10.1080/03014460.2025.2589079
What was done
A systematic review and meta-analysis examining secular trends in age at menarche among healthy Norwegian females born from 1840 to 2008. The authors searched PubMed, Web of Science, and Embase, pooling data from 17 published studies and re-analyzed individual data from 16 surveys. Analysis used weighted regression with fitted restricted cubic splines and random intercepts to adjust for within-survey correlation.
What was found
The meta-analysis included 783,757 observations across three distinct trend periods: - Women born 1840–1910: decline of -0.14 to -0.20 years per decade. - Women born 1910–1950: accelerated decline of up to -0.30 years per decade. - Women born 1950–2008: smaller, stable decline of -0.06 to -0.08 years per decade.
Why it matters
This provides comprehensive population data showing that age at menarche in Norway has declined over nearly 170 years, with the downward trend slowing but persisting in cohorts born after 1950.
Limits
Findings rely on observational and retrospective survey data vulnerable to recall bias across historical cohorts. Specific socioeconomic, nutritional, and BMI drivers were not characterized in the abstract, and results may not generalize outside Norway.
Cited by
- supports The average age of puberty onset has been continuously falling with every successive historical cohort.