Dataset Information

Association of Infant Physical Development and Rapid Growth With Pubertal Onset Among Girls in Rural China.

ABSTRACT:

Importance

Whether physical development and rapid growth during the first 2 years of life are associated with puberty onset in girls remains unclear.

Objective

To examine the associations of infant physical development and rapid growth with the timing of puberty onset in girls.

Design, setting, and participants

This prospective birth cohort study included girls whose mothers had participated in a randomized, double-blind cluster trial of micronutrient supplementation with a daily capsule of folic acid, iron and folic acid, or multiple micronutrients during pregnancy. A total of 547 singleton girls in rural western China who were born after 2004 were followed up at 3, 6, 12, and 24 months of age and were eligible for long-term follow-up. Of these, 294 adolescent girls (aged 10-12 years), representing 53.7% of the total sample, were included in the follow-up interview that was conducted from June 1 through December 31, 2016. Data analyses were conducted from November 1, 2019, to May 30, 2020.

Exposures

Infant weight and length were assessed at birth and 3, 6, 12, and 24 months of age. Rapid growth, defined as a weight-for-age or length-for-age z score increase of greater than 0.67, was calculated during 5 periods: birth to 3 months, birth to 6 months, 6 to 12 months, 12 to 24 months, and birth to 24 months of age.

Main outcomes and measures

Puberty stage was assessed using the standardized Tanner staging system. Onset of puberty was defined as attaining Tanner stage 2 of breast development or pubic hair growth, and the corresponding age at follow-up was recorded.

Results

Of 294 girls included in the analysis (mean [SD] age, 11.25 [0.57] years), the median age of puberty onset was 11 (interquartile range, 10-11) years. A significant association with puberty onset was found for infancy weight-for-age z score at 12 months of age (adjusted hazard ratio [HR], 1.20; 95% CI, 1.01-1.44) and rapid weight gain from birth to 24 months of age (adjusted HR, 1.40; 95% CI, 1.01-1.93) and birth to 3 months of age (adjusted HR, 1.39; 95% CI, 1.02-1.91). However, length-related indicators during early life were not associated with adolescent puberty onset.

Conclusions and relevance

This study found that a higher weight-for-age z score and rapid weight gain during infancy, particularly from birth to 3 months of age, were associated with an increased likelihood of puberty onset in girls. These findings suggest that weight-related indicators may serve as proxies of puberty onset among adolescent girls.

SUBMITTER: Wei J

PROVIDER: S-EPMC8094009 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundPubertal milestones, such as onset of breast development and menstruation, play an important role in breast cancer etiology. It is unclear if these milestones are different in girls with a first- or second-degree breast cancer family history (BCFH).MethodsIn the LEGACY Girls Study (n?=?1040), we examined whether three mother/guardian-reported pubertal milestones (having reached Tanner Stage 2 or higher (T2+) for breast and pubic hair development, and having started menstruation) differed by BCFH. We also examined whether associations between body size and race/ethnicity and pubertal milestones were modified by BCFH. We used mother/guardian reports as the primary measure of pubertal milestones, but also conducted sensitivity analyses using clinical Tanner measurements available for a subcohort (n?=?204). We analyzed cross-sectional baseline data with logistic regression models for the entire cohort, and longitudinal data with Weibull survival models for the subcohort of girls that were aged 5-7 years at baseline (n?=?258).ResultsBCFH was modestly, but not statistically significantly, associated with Breast T2+ (odds ratio (OR)?=?1.36, 95% confidence interval (CI)?=?0.88-2.10), with a stronger association seen in the subcohort of girls with clinical breast Tanner staging (OR?=?2.20, 95% CI?=?0.91-5.32). In a longitudinal analysis of girls who were aged 5-7 years at baseline, BCFH was associated with a 50% increased rate of having early breast development (hazard ratio (HR)?=?1.49, 95% CI?=?1.0-2.21). This association increased to twofold in girls who were not overweight at baseline (HR?=?2.04, 95% CI?=?1.29-3.21). BCFH was not associated with pubic hair development and post-menarche status. The median interval between onset of breast development and menarche was longer for BCFH+ than BCFH- girls (2.3 versus 1.7 years), suggesting a slower developmental tempo for BCFH+ girls. Associations between pubertal milestones and body size and race/ethnicity were similar in girls with or without a BCFH. For example, weight was positively associated with Breast T2+ in both girls with (OR?=?1.06 per 1 kg, 95% CI?=?1.03-1.10) and without (OR?=?1.14 per 1 kg, 95% CI?=?1.04-1.24) a BCFH.ConclusionsThese results suggest that BCFH may be related to earlier breast development and slower pubertal tempo independent of body size and race/ethnicity.