Minipuberty of Infancy and the Timing of Pubertal Development in Adolescence: a Follow-up of the Infant Feeding and Early Development (IFED) Cohort

Overview

Background: Earlier puberty is associated with adverse health throughout a person s life. The average age when puberty begins has been declining over the past decades in girls, and may also be declining in boys. The reasons for this shift are unknown. Objective: To determine whether internal (physical, hormonal) or external (feeding, environment) factors during infancy affect growth and the timing of puberty. Eligibility: Mothers (or other parent/guardian) and their children who completed the Infant Feeding and Early Development (IFED) study. Design: Participants will complete all activities at home for this natural history study. Participant mothers will fill out two 15-minute questionnaires: * One will be about themselves. They will answer questions about their body size in childhood, their puberty, and their pregnancies. * The other will be about their child. They will answer questions about their child s puberty and lifestyle. Child participants will fill out a questionnaire about their body changes during puberty. This will take 10 minutes. Participants will be sent an electronic scale and a measuring tape. They will measure the child s weight, height, and waist and hip circumference. These numbers can be submitted online or by phone or mail. Participants will receive a kit for collecting urine samples. Child participants will collect urine in a cup upon waking 4 days in a row. A special filter card is dipped in the cup then hung to dry. The dried cards will be mailed back. Participants will allow researchers to access their child s medical records. Questionnaires and body measurements will be repeated after 6 and 12 months. Urine sample collection will be repeated after 12 months. All questionnaires can be done either online, by mail, or by phone on request.

Study Description: Our overarching hypothesis is that endogenous and exogenous factors related to hypothalamic-pituitary-gonadal (HPG) axis activity during minipuberty of infancy are associated with childhood growth, the timing of pubertal development, and HPG axis activity in adolescence. To examine this hypothesis, we will conduct an observational follow-up study of children previously enrolled as infants in the Infant Feeding and Early Development (IFED) cohort. This follow-up study will be conducted remotely with data collection via email/online, mail and telephone by contractors at DLH, working on behalf of NIEHS. Objectives: Primary Objective: To assess whether endogenous (e.g. hormone concentrations and size of hormone-sensitive organs) and exogenous (e.g. infant feeding method, exposure to endocrine disrupting chemicals) factors during minipuberty of infancy are related to a) growth, b) timing of pubertal development, and c) HPG axis activity in adolescence. Endpoints: Primary Endpoints: 1. Height, weight and body mass index (BMI) 2. Onset of breast, pubic hair and/or genital development 3. Urinary metabolites of reproductive hormones (e.g. gonadotropins and sex steroids)