Is the timing of menarche correlated with mortality and fertility rates?

Abstract

Timing of menarche has largely been studied in the context of a secular trend. However, since mortality and fertility rates are fundamental demographic factors linked to a population's developmental and reproductive characteristics, we expect that the timing of menarche, a precondition to reproduction, is also associated with these vital rates. We conduct an analysis of 89 countries and 21 demographic, socioeconomic, nutritional, and educational variables selected for their known influence on menarche. Model results predict that a country's fertility and adult female mortality rates are significant predictors of mean age at menarche, while other covariates are not. Specifically, menarche is delayed in countries with high mortality and high fertility, which may be proxies for assessing overall environmental quality. We emphasize that, for a comprehensive understanding of the timing of menarche, it is critical to take into account both individual- and population-level influences.

Fig 1. Global distribution of the dependent covariate mean age at menarche for 89 countries included in the sample.

Each country is plotted by mean age at menarche from a given year. Legend shows scaled ages at menarche.

Fig 2. Graphical representation of the main findings.

Arrows depict bidirectional associations of individual- and population-level covariates with the timing of menarche. Circles filled with italic and bold point to the model results.