Female reproductive development: A hazards model analysis

Abstract

In this paper we applied a recently developed statistical technique, hazard modelling, to the study of menarche and adolescent subfecundity. Using data collected in Bangladesh in 1976 and 1977, which included anthropometric and socioeconomic status measures, we found that age and weight were significant predictors of menarche; no other measure of growth significantly added explanatory power. Weight was at least as good as other more complex measures, including the fat index proposed by Frisch. Low SES was associated with later age at menarche and appears to act through slower growth. Whenever weight was included in an analysis, the SES effects were not significant. Finally, although low SES tends to delay menarche, it seems to have little effect on the interval of adolescent subfecundity. Indeed, late maturers exhibit some degree of “catching up” in that the length of the subfecundity interval is negatively related to age at menarche.

The study also has a methodological focus. We demonstrate that use of hazard models permits more detailed and penetrating findings to be extracted from the kinds of retrospective data traditionally collected as well as from longitudinal data of the types only recently available. In particular, multivariate analysis of age at menarche and the subfecundity interval, and their relations to anthropometric time‐varying covariates as well as socioeconomic indicators, is shown to be feasible and informative.