# Longitudinal study of endocrine disrupting chemical exposure and the early hormonal milieu of girls around the time of thelarche

> **NIH NIH R01** · UNIVERSITY OF CINCINNATI · 2020 · $207,721

## Abstract

PROJECT SUMMARY:
Longitudinal Study of Endocrine-Disrupting Chemical Exposure and the Early Hormonal Milieu of Girls
Around the Time of Thelarche
 Endocrine disrupting chemicals (EDCs) are exogenous substances which exhibit hormonal activity in
the endocrine system, disrupting the physiologic function of endogenous hormones. The peri-pubertal period
represents a developmental window of vulnerability to environmental exposures in which EDCs may act as
agonists or antagonists to endogenous hormones. Evidence directly linking EDCs and alterations in pubertal
development in human populations is far from conclusive. Evidence directly linking exposure to EDCs and
changes in serum steroid hormone levels in girls around the time of breast development is almost non-existent.
 Previous studies of pubertal girls (both in our cohort and others) have reported that exposure to certain
EDCs is associated with either later or earlier thelarche and menarche suggesting that EDCs may have an
effect on the hormonal milieu in pubertal girls. None of these studies has examined whether a mixture of
environmental exposures is related to age at pubertal events. Knowledge about the structural relationship
regarding the direct effect of EDCs on hormone levels in girls and then the timing and intensity of later pubertal
events, such as age at thelarche, age at menarche, pubertal tempo, peak height velocity, and age at peak
height, is lacking. With the measurement of multiple environmental biomarkers in our cohort of girls, we can
develop metrics for mixtures of environmental exposures and use these metrics in our analyses. With our
prospective study design including direct observation of pubertal maturation events and measurements of
steroid hormones in serum around the time of thelarche, we can examine the effect of exposure to EDCs on
these events using structural equation models. Our study proposes to fill the gap in knowledge regarding
whether exposure to EDCs has a direct effect on the hormonal milieu in pubertal girls, and how these changes
in are related to age at pubertal milestones.
 This application is highly innovative because of its unique design: girls have been evaluated
longitudinally from ages 6-7 years, with serum hormone measurements during time points around thelarche,
and measurements of environmental biomarkers prior to puberty. Our hypotheses are novel. Using existing
prospectively collected pubertal maturation and environmental biomarker data, and recently acquired
measurements of serum hormones in banked serum samples timed to maturation events, in a group of girls
followed since ages 6 and 7, we will directly addresses the gaps noted in the 2013 IBCERCC report “Breast
Cancer and the Environment: Prioritizing Prevention”. The impact of this proposal is to provide information that
will lead to the identification of mechanisms of EDCs and targetable pathways, resulting in strategies to
minimize disruption in the timing of pubertal events in girls and f...

## Key facts

- **NIH application ID:** 9934200
- **Project number:** 5R01ES029133-03
- **Recipient organization:** UNIVERSITY OF CINCINNATI
- **Principal Investigator:** FRANK M BIRO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $207,721
- **Award type:** 5
- **Project period:** 2018-08-15 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9934200

## Citation

> US National Institutes of Health, RePORTER application 9934200, Longitudinal study of endocrine disrupting chemical exposure and the early hormonal milieu of girls around the time of thelarche (5R01ES029133-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9934200. Licensed CC0.

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