Environmental Phenols and Growth in Infancy: The Infant Feeding and Early Development Study.

Context: Higher mean and rapid increases in body mass index (BMI) during infancy are associated with subsequent obesity and may be influenced by exposure to endocrine-disrupting chemicals such as phenols.

Objective: In a prospective US-based cohort conducted 2010-2014, we investigated associations between environmental phenol exposures and BMI in 199 infants.

Methods: We measured 7 urinary phenols at ages 6-8 and 12 weeks and assessed BMI z-score at up to 12 study visits between birth and 36 weeks.

Environmental phenol exposures in 6- to 12-week-old infants: The Infant Feeding and Early Development (IFED) study.

Background: Exposure to phenols, endocrine-disrupting chemicals used in personal care and consumer products, is widespread. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period. We aimed to describe distributions and predictors of urinary phenol concentrations among U.

Personal Care Product Use during Puberty and Incident Breast Cancer among Black, Hispanic/Latina, and White Women in a Prospective US-Wide Cohort.

Background: Some personal care products (PCPs) contain endocrine-disrupting chemicals that may affect breast cancer (BC) risk. Patterns of use vary by race and ethnicity. Use often starts in adolescence, when rapidly developing breast tissue may be more susceptible to environmental carcinogens.

Childhood physical activity and pubertal timing: findings from the LEGACY girls study.

Background: There is limited research on whether physical activity (PA) in early childhood is associated with the timing of pubertal events in girls.

Methods: We used data collected over 2011-16 from the LEGACY Girls Study (n = 984; primarily aged 6-13 years at study enrolment), a multicentre North American cohort enriched for girls with a breast cancer family history (BCFH), to evaluate if PA is associated with age at thelarche, pubarche and menarche. Maternal-reported questionnaire data measured puberty outcomes, PA in early childhood (ages 3-5 years) and total metabolic equivalents of organized PA in middle childhood (ages 7-9 years).

Use of personal care product mixtures and incident hormone-sensitive cancers in the Sister Study: A U.S.-wide prospective cohort.

Background: Personal care products (PCPs), a source of endocrine-disrupting chemical exposure, may be associated with the risk of hormone-sensitive cancers. Few studies have investigated associations for PCP use with the incidence of hormone-sensitive cancers or considered the joint effect of multiple correlated PCPs. We examined associations between frequently used, or "everyday", PCPs and incident cancers of the breast, ovary, and uterus with a fucus on the joint effect of multiple product exposure.

Region of origin and cervical cancer stage in multiethnic Hispanic/Latinx patients living in the United States.

Background: Hispanic/Latinx people have the second highest cervical cancer incidence rates in the U.S. However, there is a lack of disaggregated data on clinical outcomes for this diverse and populous group, which is critical to direct resources and funding where they are most needed.

Hypertensive conditions of pregnancy, preterm birth, and premenopausal breast cancer risk: a premenopausal breast cancer collaborative group analysis.

Purpose: Women with preeclampsia are more likely to deliver preterm. Reports of inverse associations between preeclampsia and breast cancer risk, and positive associations between preterm birth and breast cancer risk are difficult to reconcile. We investigated the co-occurrence of preeclampsia/gestational hypertension with preterm birth and breast cancer risk using data from the Premenopausal Breast Cancer Collaborative Group.

Early Life Anti-Müllerian Hormone Trajectories in Infant Girls.

Background: Minipuberty is a period of increased reproductive axis activity in infancy, but the importance of this period is not well understood, especially in girls. Previous studies reported a peak in hormone concentrations at 3 to 4 months old. Our objective is to describe anti-Müllerian hormone (AMH) trajectories in the context of other minipuberty factors among healthy infant girls using longitudinal measures of AMH.

Gestational Hypertensive Disorders and Maternal Breast Cancer Risk in a Nationwide Cohort of 40,720 Parous Women.

Background: Preeclampsia and gestational hypertension are hypothesized to be associated with reduced maternal breast cancer risk, but the epidemiologic evidence is inconclusive. Our objective was to examine associations between gestational hypertensive disorders and breast cancer in a nationwide cohort of women with a family history of breast cancer.

Methods: Women ages 35-74 years who had a sister previously diagnosed with breast cancer, but had never had breast cancer themselves, were enrolled in the Sister Study from 2003 to 2009 (N = 50,884).

The importance of addressing early life environmental exposures in cancer epidemiology.

Purpose Of Review: Environmental exposures during early stages of life may be particularly relevant for cancer etiology because of the rapid hormonal and tissue changes that occur during puberty and, in women, through first birth. We review evidence from the past five years on environmental exposures during childhood/adolescence through first birth and the risk of breast and other cancers during adulthood.

Recent Findings: The studies of breast cancer (n=14) reported associations for childhood/adolescent environmental tobacco smoke (ETS), smoking initiation, pesticides, hair dye use, and living on a road with high traffic.

Maternal and prenatal factors and age at thelarche in the LEGACY Girls Study cohort: implications for breast cancer risk.

Background: Earlier onset of breast development (thelarche) is associated with increased breast cancer risk. Identifying modifiable factors associated with earlier thelarche may provide an opportunity for breast cancer risk reduction starting early in life, which could especially benefit girls with a greater absolute risk of breast cancer due to family history.

Methods: We assessed associations of maternal pre-pregnancy body mass index (BMI), physical activity during pregnancy, gestational weight gain and daughters' weight and length at birth with age at thelarche using longitudinal Weibull models in 1031 girls in the Lessons in Epidemiology and Genetics of Adult Cancer from Youth (LEGACY) Girls Study-a prospective cohort of girls, half of whom have a breast cancer family history (BCFH).

Body mass index rebound and pubertal timing in girls with and without a family history of breast cancer: the LEGACY girls study.

Background: Heavier body mass index (BMI) is the most established predictor of earlier age at puberty. However, it is unknown whether the timing of the childhood switch to heavier BMI (age at BMI rebound) also matters for puberty.

Methods: In the LEGACY Girls Study (n = 1040), a longitudinal cohort enriched with girls with a family history of breast cancer, we collected paediatric growth chart data from 852 girls and assessed pubertal development every 6 months.

Early-life exposures and age at thelarche in the Sister Study cohort.

Background: Early age at breast development (thelarche) has been associated with increased breast cancer risk. Average age at thelarche has declined over time, but there are few established risk factors for early thelarche. We examined associations between pre- and postnatal exposures and age at thelarche in a US cohort of women born between 1928 and 1974.

Urinary and salivary endocrine measurements to complement Tanner staging in studies of pubertal development.

Background: Many studies investigating pubertal development use Tanner staging to assess maturation. Endocrine markers in urine and saliva may provide an objective, sensitive, and non-invasive method for assessing development.

Objective: Our objective was to examine whether changes in endocrine levels can indicate the onset of pubertal development prior to changes in self-rated Tanner stage.

Benign breast disease and changes in mammographic breast density.

Background: Mammographic breast density (MBD) and benign breast disease (BBD) are two of the strongest risk factors for breast cancer. Understanding trends in MBD by age and parity in women with BBD is essential to the clinical management and prevention of breast cancer.

Methods: Using data from the Early Determinants of Mammographic Density (EDMD) study, a prospective follow-up study of women born in 1959-1967, we evaluated MBD in 676 women.

Common Childhood Viruses and Pubertal Timing: The LEGACY Girls Study.

Earlier pubertal development is only partially explained by childhood body mass index; the role of other factors, such as childhood infections, is less understood. Using data from the LEGACY Girls Study (North America, 2011-2016), we prospectively examined the associations between childhood viral infections (cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) 1, HSV2) and pubertal timing. We measured exposures based on seropositivity in premenarcheal girls (n = 490).

Pubertal timing and breast cancer risk in the Sister Study cohort.

Background: Earlier age at menarche is an established risk factor for breast cancer. While age at menarche has been fairly stable over the past half-century, age at breast development (thelarche) has continued to decrease. Recently, earlier age at thelarche and a longer time between thelarche and menarche (pubertal tempo) were shown to be associated with increased breast cancer risk.

Circulating growth factor concentrations and breast cancer risk: a nested case-control study of IGF-1, IGFBP-3, and breast cancer in a family-based cohort.

Background: Insulin-like growth factor 1 (IGF-1) and binding protein 3 (IGFBP-3) are associated with breast cancer in women at average risk of cancer. Less is known whether these biomarkers also predict risk in women with breast cancer family history.

Methods: We conducted a nested case-control study within the New York site of the Breast Cancer Family Registry (BCFR, n = 80 cases, 156 controls), a cohort enriched for breast cancer family history.

Prepubertal Internalizing Symptoms and Timing of Puberty Onset in Girls.

Stressful environments have been associated with earlier menarche. We hypothesized that anxiety, and possibly other internalizing symptoms, are also associated with earlier puberty in girls. The Lessons in Epidemiology and Genetics of Adult Cancer From Youth (LEGACY) Girls Study (2011-2016) included 1,040 girls aged 6-13 years at recruitment whose growth and development were assessed every 6 months.

Influence of pubertal development on urinary oxidative stress biomarkers in adolescent girls in the New York LEGACY cohort.

Puberty is a time of intense growth and differentiation of breast tissue and a window of susceptibility (WOS) for breast cancer. Although oxidative stress markers have been associated with breast cancer risk, it is unclear whether oxidative stress levels are different during the pubertal WOS, and if so, whether these differences are related to breast cancer susceptibility. We measured urinary biomarkers of whole body oxidative stress (urinary F2-Isoprostanes and 8-oxodeoxyguanosine (8-oxodG)) in 158 girls (ages 6-13 years), 71 with and 87 without a breast cancer family history (BCFH) from a cohort of adolescent girls from the New York site of the LEGACY cohort (Lessons in Epidemiology and Genetics in Adults Cancer from Youth).

Early-Life Growth and Benign Breast Disease.

Using prospective data from the Early Determinants of Mammographic Density study (United States, 1959-2008, n = 1121), we examined the associations between maternal body size, birth size, and infant and early childhood growth during 3 time periods (0-4 months, 4-12 months, and 1-4 years) and benign breast disease (BBD) using multivariable logistic regression with generalized estimating equations. A total of 197 women (17.6%) reported receiving a diagnosis of BBD by a physician.

Body size at birth, early-life growth and the timing of the menopausal transition and natural menopause.

Background: Whether birth weight and early-life growth are associated with age at menopause has not been resolved.

Methods: We conducted a prospective study in two U.S.

Association of Prepubertal and Adolescent Androgen Concentrations With Timing of Breast Development and Family History of Breast Cancer.

Importance: Early breast development is a risk factor for breast cancer, and girls with a breast cancer family history (BCFH) experience breast development earlier than girls without a BCFH.

Objectives: To assess whether prepubertal androgen concentrations are associated with timing of breast development (analysis 1) and to compare serum androgen concentrations in girls with and without a BCFH (analysis 2).

Design, Setting, And Participants: Prospective cohort study of 104 girls aged 6 to 13 years at baseline using data collected between August 16, 2011, and March 24, 2016, from the Lessons in Epidemiology and Genetics of Adult Cancer From Youth (LEGACY) Girls Study, New York site.

Do Birth Weight and Weight Gain During Infancy and Early Childhood Explain Variation in Mammographic Density in Women in Midlife? Results From Cohort and Sibling Analyses.

High birth weight is associated with increased breast cancer risk and, less consistently, with higher mammographic density. In contrast, adolescent body size has been consistently, negatively associated with both MD and breast cancer risk. It is unclear when the direction of these associations changes and whether weight gain in infancy is associated with MD.