Onset of Breast Development in a Longitudinal Cohort
Onset of Breast Development in a Longitudinal Cohort
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DOI：
10.1542/peds.2012-3773
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发表时间：
2013-12-01
期刊：
影响因子：
8
通讯作者：
Wolff, Mary S.
中科院分区：
文献类型：
--
作者：
Biro, Frank M.;Greenspan, Louise C.;Wolff, Mary S.
背景和目的：越来越多的证据表明青春期成熟发生在较早的年龄，许多研究都是基于横断面观察。本研究在乳腺癌和环境研究计划的 3 个青春期研究中心（由 1200 名女孩组成的前瞻性队列）中检查了乳房发育开始的年龄（乳房发育）以及 BMI 和种族/民族的影响。方法：从 2004 年到 2011 年，在 3 个地理区域（旧金山湾区、大辛辛那提和纽约市）定期对入组时 6 至 8 岁的女孩进行纵向随访。使用 Tanner 分期的性成熟评估是由经过培训和认证的工作人员使用标准化观察和触诊方法进行的。 Kaplan-Meier 分析用于通过协变量描述乳房成熟开始的年龄。结果：乳房第 2 阶段开始的年龄因种族/民族、基线 BMI 和部位而异。非裔美国人、西班牙裔、非西班牙裔白人和亚洲参与者的乳房第 2 期发病的中位年龄分别为 8.8、9.3、9.7 和 9.7 岁。 BMI 较高的女孩在更年轻的时候就达到了乳房第 2 阶段。乳房成熟的年龄特异性和标准化患病率与 10 至 20 年前进行的两项大型横断面研究（办公室环境中的儿科研究和国家健康与营养检查调查 III）的观察结果进行了对比，发现白人、非西班牙裔女孩而非非裔美国女孩的乳房成熟率发生得更早。结论：我们观察到乳房发育的年龄比之前记录的更年轻，与种族/民族和体重指数相关的重要差异，证实和扩展了所观察到的模式以前。这些发现与 BMI 的时间变化一致。
BACKGROUND AND OBJECTIVES: There is growing evidence of pubertal maturation occurring at earlier ages, with many studies based on cross-sectional observations. This study examined age at onset of breast development (thelarche), and the impact of BMI and race/ ethnicity, in the 3 puberty study sites of the Breast Cancer and the Environment Research Program, a prospective cohort of.1200 girls.METHODS: Girls, 6 to 8 years at enrollment, were followed longitudinally at regular intervals from 2004 to 2011 in 3 geographic areas: the San Francisco Bay Area, Greater Cincinnati, and New York City. Sexual maturity assessment using Tanner staging was conducted by using standardized observation and palpation methods by trained and certified staff. Kaplan-Meier analyses were used to describe age at onset of breast maturation by covariates.RESULTS: The age at onset of breast stage 2 varied by race/ethnicity, BMI at baseline, and site. Median age at onset of breast stage 2 was 8.8, 9.3, 9.7, and 9.7 years for African American, Hispanic, white non-Hispanic, and Asian participants, respectively. Girls with greater BMI reached breast stage 2 at younger ages. Age-specific and standardized prevalence of breast maturation was contrasted to observations in 2 large cross-sectional studies conducted 10 to 20 years earlier (Pediatric Research in Office Settings and National Health and Nutrition Examination Survey III) and found to have occurred earlier among white, non-Hispanic, but not African American girls.CONCLUSIONS: We observed the onset of thelarche at younger ages than previously documented, with important differences associated with race/ethnicity and BMI, confirming and extending patterns seen previously. These findings are consistent with temporal changes in BMI.