Holme A, MacArthur C, Lancashire R
Bristol Royal Infirmary, Bristol, UK.
Child Care Health Dev. 2010 Jul;36(4):583-90. doi: 10.1111/j.1365-2214.2009.01068.x. Epub 2010 Feb 23.
The effect of breastfeeding on cognitive development in the child remains controversial. The commonly observed association between breastfeeding and higher intelligence quotient (IQ) scores in children may result from the numerous confounding factors in this complex relationship. The aim of this study was to examine whether breastfeeding is associated with later differences in children's cognitive and neurological development.
Secondary analysis from a 9-year follow-up study of children of 982 smokers recruited to a randomized controlled trial of anti-smoking education in pregnancy in a maternity hospital between November 1981 and October 1982; and all ex-smokers and a random 25% sample of non-smokers during the same period (total 1853 women). Cognitive and neurological development of children was assessed by psychologists in schools using the British Ability Scales and Quick Neurological Screening Test (QNST). Data on breastfeeding and factors relevant to child development were drawn from interviews with mothers at home. Main outcome measures were IQ and QNST scores.
A total of 1218 (66%) children were followed up. In total, 61.6% of children were breastfed, median duration being 12 weeks. Before adjustment, breastfeeding was significantly associated with higher total, verbal and visual IQ scores in children, and increasing duration was significantly correlated with IQ scores. Total IQ was 5.49 points higher in breastfed children (P< or = 0.001), but became non-significant after adjustment. Total IQ scores were most strongly associated with maternal education, maternal age, parity, housing and chronic childhood illness. Breastfeeding was significantly associated with better QNST scores on bivariate analysis but not after adjustment. QNST scores were most strongly associated with maternal education and the child's sex.
Breastfeeding was not associated with any crude IQ advantage or difference in neurological soft signs in children at 9 years. The greater IQ score associated with breastfeeding is accounted for by confounding, with maternal and socio-economic characteristics particularly important.
母乳喂养对儿童认知发育的影响仍存在争议。母乳喂养与儿童较高智商（IQ）分数之间常见的关联可能源于这种复杂关系中的众多混杂因素。本研究的目的是探讨母乳喂养是否与儿童后期认知和神经发育差异相关。
对1981年11月至1982年10月在一家妇产医院招募的982名吸烟孕妇进行的一项关于孕期戒烟教育的随机对照试验中儿童的9年随访研究进行二次分析；以及同期所有已戒烟者和25%随机抽取的非吸烟者样本（共1853名女性）。学校心理学家使用英国能力量表和快速神经筛查测试（QNST）对儿童的认知和神经发育进行评估。关于母乳喂养和与儿童发育相关因素的数据来自在家中对母亲的访谈。主要结局指标为IQ和QNST分数。
共对1218名（66%）儿童进行了随访。总体而言，61.6%的儿童进行了母乳喂养，中位持续时间为12周。在调整前，母乳喂养与儿童较高的总IQ、语言IQ和视觉IQ分数显著相关，且持续时间增加与IQ分数显著相关。母乳喂养儿童的总IQ高5.49分（P≤0.001），但调整后变得不显著。总IQ分数与母亲教育程度、母亲年龄、产次、住房和儿童慢性疾病最密切相关。在双变量分析中，母乳喂养与更好的QNST分数显著相关，但调整后不相关。QNST分数与母亲教育程度和儿童性别最密切相关。
母乳喂养与9岁儿童的任何原始IQ优势或神经软体征差异均无关联。与母乳喂养相关的较高IQ分数是由混杂因素导致的，其中母亲和社会经济特征尤为重要。
