Dept. of Growth and Reproduction, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Copenhagen University Hospital -Rigshospitalet, Copenhagen, Denmark.
Front Endocrinol (Lausanne). 2022 Dec 1;13:1048660. doi: 10.3389/fendo.2022.1048660. eCollection 2022.
Breast tissue in infancy is a rather undescribed phenomenon. We aimed to describe the prevalence and progression of palpable breast tissue in healthy boys and girls aged 0-1 years and to evaluate clinical markers, individual serum hormone concentrations as well as combined hormone profiles as determinants of the persistence of breast tissue.
In total, 233 term infants (119 boys, 114 girls) were included and followed from birth until 1 year of age in The COPENHAGEN Minipuberty Study (ClinicalTrials.gov #NTC02784184). Infants were followed up to six times with a clinical examination and serum sampling. Principal component analyses (PCAs) produced combined hormone profiles.
A total of 98% of all infants aged 0-1 year exhibited breast tissue at some point. 50% still had breast tissue present at 0.5-0.6 years in girls and 0.3-0.4 years in boys ('persistent'). At one year, more girls than boys had breast tissue present (p=0.010). Most clinical and hormonal markers did not differ in infants with/without persistent breast tissue. However, in those with persistent breast tissue, estradiol (first visit, girls, p=0.034), androstenedione, corticosterone, cortisol (first visit, boys, all p<0.050), length (first visit, boys, p=0.030), and testicular volume (0.3-0.4 years, p=0.040) were higher, while IGF-I (0.3-0.4, boys, p=0.033) was lower. In boys, a combined, PCA-derived hormone profile (first visit) was able to predict the persistence of breast tissue (area under the curve=83%) better than any single marker.
Palpable breast tissue in infancy is common in both sexes although it persists in significantly more girls than boys at one year of age. Data supports both the early origin of breast tissue (- and early postnatal) as well as a role of endogenous hormone production in later development and maintenance.
婴儿期的乳腺组织是一个尚未被充分描述的现象。我们旨在描述健康男婴和女婴 0-1 岁时可触及乳腺组织的发生率和进展，并评估临床标志物、个体血清激素浓度以及联合激素谱作为乳腺组织持续存在的决定因素。
共有 233 名足月婴儿（男婴 119 名，女婴 114 名）被纳入 COPENHAGEN 婴儿期微量研究（ClinicalTrials.gov #NTC02784184），并从出生开始随访至 1 岁。婴儿在 6 次随访中接受临床检查和血清取样。主成分分析（PCA）生成联合激素谱。
所有 0-1 岁的婴儿中，共有 98%的婴儿在某个时间点出现乳腺组织。50%的女孩在 0.5-0.6 岁，男孩在 0.3-0.4 岁时仍有乳腺组织存在（“持续存在”）。1 岁时，女孩中出现乳腺组织的比例高于男孩（p=0.010）。在有/无持续乳腺组织的婴儿中，大多数临床和激素标志物无差异。然而，在持续存在乳腺组织的婴儿中，雌二醇（首次就诊，女孩，p=0.034）、雄烯二酮、皮质酮、皮质醇（首次就诊，男孩，均 p<0.050）、身高（首次就诊，男孩，p=0.030）和睾丸体积（0.3-0.4 岁，p=0.040）更高，而 IGF-I（0.3-0.4 岁，男孩，p=0.033）更低。在男孩中，首次就诊时的一种联合 PCA 衍生激素谱（first visit）能够更好地预测乳腺组织的持续存在（曲线下面积=83%）。
婴儿期可触及的乳腺组织在男婴和女婴中均很常见，但在 1 岁时，女孩中持续存在的比例明显高于男孩。数据支持乳腺组织的早期起源（-和新生儿期后）以及内源性激素产生在后期发育和维持中的作用。
