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

2022

1546-1555

12/2022

1464-3685

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.

10.1093/ije/dyac021

Int J Epidemiol

35157067

Mother and daughter perspectives on genetic counseling and testing of adolescents for hereditary breast cancer risk.

2022

06/2022

1097-6833

OBJECTIVE: To evaluate the risks, benefits, and utility of testing for adult-onset hereditary breast and ovarian cancer (HBOC) in adolescents and young adults.

STUDY DESIGN: We evaluated interest in genetic testing of adolescents for adult-onset HBOC genes through semistructured interviews with mothers and adolescents who had previously participated in breast cancer research or had pursued (mothers) clinical testing for HBOC.

RESULTS: The majority of mothers (73%) and daughters (75%) were interested in the daughter having genetic testing and were motivated by the future medical utility and current social utility of relieving anxiety and allowing them to prepare. Mothers and daughters both reported that approximately 3 years in the future was the best time to test the daughter regardless of the current age of the daughter. Overall, both mothers and daughters expressed the importance of the involvement of the mother to provide educational and emotional support but ultimately it was the daughter's decision to test. Balancing the independence and maturity of the daughter while reinforcing communication and support within the dyad was a prominent theme throughout the interviews.

CONCLUSIONS: There is interest among some high-risk adolescents and young adults to engage in genetic counseling and undergo testing. Providing pretest and posttest genetic counseling, assessing preferences for parent involvement, and offering psychosocial support may be important if genetic testing for HBOC is offered to adolescents and young adults before age 25 years.

10.1016/j.jpeds.2022.06.027

J Pediatr

35777474

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

2022

2022 Feb 14

1464-3685

<p><strong>BACKGROUND: </strong>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.</p>

<p><strong>METHODS: </strong>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.</p>

<p><strong>RESULTS: </strong>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.</p>

<p><strong>CONCLUSIONS: </strong>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.</p>

10.1093/ije/dyac021

Int J Epidemiol

35157067