Mean age at menarche and climate variables on a global scale

Area of Science:

• Human evolutionary biology
• Anthropology
• Climate science

Background:

• Age at menarche exhibits significant cross-population variation.
• Numerous factors influence the timing of menarche across diverse human groups.

Purpose of the Study:

• To investigate the relationship between climate variables and the mean age at menarche.
• To analyze these associations across 87 distinct modern human populations.

Main Methods:

• Utilized a comparative dataset encompassing geospatial distribution and climate data.
• Examined climate variables in relation to age at menarche for 87 populations.

Main Results:

• Higher fertility rates and later mean age at death were the strongest predictors of a later age at menarche.
• Increased annual rainfall, higher precipitation seasonality, and lower annual mean temperature were moderate predictors.

Conclusions:

• Later age at menarche in high-fertility populations may represent a life-history adaptation to climatic conditions.
• These conditions potentially increase immunological load, leading females to prioritize growth over reproduction.
• Climate shifts and population growth could alter future patterns of age at menarche.