Statistical Methods In Human Development/clinical Studies

National Institute Of Environmental Health Sciences

Investigators

Linked publications, trials & patents

Abstract

This year, work has focused primarily on the application of statistical methods to studies on the effects of soy formula on the development of neonates. We have also worked on methods for pooled exposure assessment in case-cohort studies. Data collection for a study of the effects of soy estrogen on neonatal development carried out at Children's Hospital of Philadelphia has been completed (collaboration with Walter Rogan, formerly EB, now retired). Currently, work is focused on understanding whether the testosterone surge during minipuberty in male infants is associated with the concurrent size and growth velocity of the infant’s body (length and weight) and of certain anatomical structures (anogenital distance, stretched penile length, and testis volume). Though the phenomenon of minipuberty has long been recognized, its role in infant growth and development remains uncertain. We have been refining methods that employ radial smoothing of age trajectories to summarize both testosterone concentrations and anatomical features throughout infancy for each subject. We intend to use those age trajectories to calculate average testosterone levels during selected age ranges and, similarly, to estimate average size and growth rates of anatomical features during corresponding age ranges. After the age-range-specific testosterone levels and anatomical characteristics are calculated, we will assess their possible associations using regression methods. We have a long interest in developing epidemiologic methods for analyzing disease associated with environmental exposures when the exposures are assayed in pooled specimens from several individuals. The motivation is to save assay costs while retaining as much power and precision in the statistical analysis as possible. Previously, we introduced the analysis of pooled biospecimens for case-control studies. In this review period, we expanded those methods to case-cohort studies. (see also Z01 ES040007; PI Clare Weinberg; Min Shi is also a within-lab collaborator whose time is allocated on that report.)