Barros F C, Victora C G, Vaughan J P, Smith P G
Pediatrics. 1986 Oct;78(4):656-61.
The beneficial effects of breast-feeding on infant mortality and morbidity have been demonstrated in many studies. Few of these, however, have taken into account the possible confounding effect of birth weight. Several studies have shown that babies of low birth weight are less likely to be breast-fed. In some circumstances, this alone may account for a more than twofold excess in postperinatal infant mortality rates among non-breast-fed babies, even in the absence of any beneficial effect of breast-feeding. The association between birth weight and breast-feeding and the magnitude of the confounding effect is illustrated using data from a longitudinal study of infant mortality in Pelotas, Southern Brazil, and also using published results from other studies. It is concluded that studies designed or analyzed to relate breast-feeding to infant mortality should take the confounding effect of birth weight into account to avoid overestimating the beneficial effects of human milk.
许多研究已证实母乳喂养对婴儿死亡率和发病率具有有益影响。然而，其中很少有研究考虑到出生体重可能产生的混杂效应。多项研究表明，低出生体重的婴儿进行母乳喂养的可能性较小。在某些情况下，即便母乳喂养没有任何有益效果，仅这一点就可能导致非母乳喂养婴儿的围产期后死亡率高出两倍多。本文利用巴西南部佩洛塔斯一项关于婴儿死亡率的纵向研究数据以及其他研究的已发表结果，阐述了出生体重与母乳喂养之间的关联以及混杂效应的程度。得出的结论是，旨在研究母乳喂养与婴儿死亡率之间关系的设计或分析研究应考虑出生体重的混杂效应，以避免高估母乳的有益效果。
