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

TitleBody mass index rebound and pubertal timing in girls with and without a family history of breast cancer: the LEGACY girls study.
Publication TypeJournal Article
Year of Publication2022
AuthorsHoughton LC, Wei Y, Wang T, Goldberg M, Paniagua-Avila A, Sweeden RL, Bradbury A, Daly M, Schwartz LA, Keegan T, John EM, Knight JA, Andrulis IL, Buys SS, Frost CJ, O'Toole K, White ML, Chung WK, Terry MBeth
JournalInt J Epidemiol
Date Published2022 Feb 14
ISSN1464-3685
Abstract

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. Using constrained splines, we interpolated individual growth curves and then predicted BMI at ages 2, 4, 6, 8 and 9 years for 591 girls. We defined age at BMI rebound as the age at the lowest BMI between ages 2 and 8 years and assessed its association with onset of thelarche, pubarche and menarche using Weibull survival models.

RESULTS: The median age at BMI rebound was 5.3 years (interquartile range: 3.6-6.7 years). A 1-year increase in age at BMI rebound was associated with delayed thelarche (HR = 0.90; 95% CI = 0.83-0.97) and menarche (HR = 0.86; 95% CI = 0.79-0.94). The magnitude of these associations remained after adjusting for weight between birth and 2 years, was stronger after adjusting for BMI at age 9, and was stronger in a subset of girls with clinically assessed breast development.

CONCLUSIONS: Earlier BMI rebound is associated with earlier pubertal timing. Our observation that BMI rebound may be a driver of pubertal timing in girls with and without a family history of breast cancer provides insight into how growth and pubertal timing are associated with breast cancer risk.

DOI10.1093/ije/dyac021
Alternate JournalInt J Epidemiol
PubMed ID35157067
Grant ListK07CA218166 to L.C.H. / / National Cancer Institute at the National Institutes of Health /