Childhood Nutrition Research Centre, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
Proc Nutr Soc. 2011 Nov;70(4):472-7. doi: 10.1017/S0029665111000589. Epub 2011 Aug 1.
The relationship between breast-feeding and later cardiovascular health has been investigated in randomised trials and observational studies. This review focuses on randomised control trials, regarded as the 'gold standard' in establishing causal relationships between interventions and outcomes. Since it is not ethical to randomise healthy term infants to be breast- or formula-fed, only two randomised control trials have examined effects of breast-feeding on later health. In one randomised control trial, preterm infants randomised to receive banked donor breast milk had significantly lower blood pressure (BP), more favourable plasma lipid profile and reduced leptin resistance at age of 13-15 years compared with those who were fed preterm formula; with a dose-response relationship between the proportion of human milk and later outcomes. In contrast, a cluster-randomised control trial of a breast-feeding promotion intervention in healthy term infants (Promotion of Breast-feeding Intervention Trial study) found no effect of the intervention on adiposity or BP at 6 years, despite increased incidence, duration and exclusivity of breast-feeding. Potential explanations for the discrepancy between the two studies include: (i) beneficial effects of breast milk on cardiovascular health might be confined to preterm infants; (ii) effects on cardiovascular outcomes may not manifest until adolescence, a concept supported by other studies; (iii) if the underlying mechanism for the effect of breast-feeding on later cardiovascular outcome is slower early growth; a concept supported by data from animal models, human observational studies and now experimental studies in human subjects; it is plausible that differences in early growth between groups in the Promotion of Breast-feeding Intervention Trial were insufficient to produce a detectable effect on these outcomes.
母乳喂养与后期心血管健康之间的关系已经在随机试验和观察性研究中进行了研究。本综述重点介绍了随机对照试验，这些试验被认为是确定干预措施与结果之间因果关系的“金标准”。由于将健康足月婴儿随机分配进行母乳喂养或配方奶喂养在伦理上是不可行的，因此只有两项随机对照试验研究了母乳喂养对后期健康的影响。在一项随机对照试验中，与接受早产儿配方奶喂养的婴儿相比，接受银行捐赠母乳的早产儿在 13-15 岁时血压（BP）明显更低、血浆脂质谱更有利、瘦素抵抗降低；并且母乳比例与后期结果之间存在剂量反应关系。相比之下，一项健康足月婴儿母乳喂养促进干预的集群随机对照试验（母乳喂养促进干预试验研究）发现，干预措施对 6 岁时的肥胖或血压没有影响，尽管母乳喂养的发生率、持续时间和排他性都有所增加。这两项研究结果存在差异的可能解释包括：（i）母乳对心血管健康的有益影响可能仅限于早产儿；（ii）对心血管结局的影响可能要到青春期才会显现，这一概念得到了其他研究的支持；（iii）如果母乳喂养对后期心血管结局的影响的潜在机制是早期生长较慢；这一概念得到了来自动物模型、人类观察性研究以及目前人类受试者的实验研究的数据的支持；如果在母乳喂养促进干预试验中，各组之间的早期生长差异不足以对这些结果产生可检测的影响，这是合理的。
