Breastfeeding practices and head circumference in young children: a systematic review

ABSTRACT OBJECTIVE To review observational studies on the association between breastfeeding (BF) practices and head circumference (HC) of children < 2 years old. METHODS A systematic review was conducted using the following electronic databases of health sciences: PubMed, Latin American and Caribbean Literature in Health Sciences (Lilacs), Web of Science and Scopus. We selected observational studies published in any language from January 01, 2010 to November 19, 2021, from different populations that investigated the association between BF practice and HC among healthy children < 2 years old. Titles and abstracts were screened independently by two evaluators. RESULTS From the 4,229 articles identified, 24 were included in this review: 6 cross-sectional, 17 longitudinal, and 1 case-control. The studies varied in their definition of the variables for BF and in reporting its practice, frequency, duration, and feeding method. Regarding HC, the authors analyzed the mean differences, abnormal values (z-score above + 2SD or below -2SD according to the World Health Organization (WHO) growth standards, 2007), and longitudinal growth parameters. The findings of this review suggest that BF may have a positive relationship with HC at the beginning of life. CONCLUSIONS Our findings suggest that BF, especially exclusive BF, may play a protective role against abnormal HC values in young children. However, more robust evidence with standardized BF indicators and WHO growth standards (2007) are required.

摘要
研究目的：系统梳理针对2岁以下儿童母乳喂养（Breastfeeding，BF）行为与头围（Head Circumference，HC）相关性的观察性研究。
研究方法：本研究采用系统综述方法，检索以下健康科学电子数据库：PubMed、拉丁美洲与加勒比健康科学文献数据库（LILACS）、Web of Science及Scopus。纳入2010年1月1日至2021年11月19日期间发表的、无论语种的观察性研究，研究对象为不同人群中健康的2岁以下儿童，旨在探讨母乳喂养行为与头围的相关性。由两名评价员独立筛选文献标题与摘要。
研究结果：初检共检索到4229篇文献，最终纳入24篇进行本综述：其中6篇为横断面研究，17篇为纵向研究，1篇为病例对照研究。各研究对母乳喂养相关变量的定义及对喂养行为、频率、持续时长与喂养方式的报告存在差异。针对头围，研究者分析了平均差值、异常值（参照2007年世界卫生组织（World Health Organization，WHO）生长标准，Z评分高于+2SD或低于-2SD的数值）及纵向生长参数。本综述结果提示，母乳喂养可能在生命早期与头围呈正相关。
研究结论：本研究结果提示，母乳喂养，尤其是纯母乳喂养，可能对幼儿头围异常值具有保护作用。但仍需采用标准化母乳喂养指标及2007年世界卫生组织生长标准开展更严谨的研究，以获取更可靠的证据。