Wright A L, Bauer M, Naylor A, Sutcliffe E, Clark L
Department of Pediatrics and Steele Memorial Children's Research Center, University of Arizona, Tucson, Arizona 85724, USA.
Pediatrics. 1998 May;101(5):837-44. doi: 10.1542/peds.101.5.837.
Although breastfeeding is associated with lower rates of a variety of infant illnesses, skeptics have suggested that much of the association is attributable to confounding, even after appropriate statistical adjustment. This article utilizes a novel design to investigate changes in infant illness at the community level after a successful breastfeeding promotion program.
In this population-based cohort study, the medical records of all infants born in one Navajo community the year before a breastfeeding promotion program (n = 977) and the year during the intervention (n = 858) were reviewed. Outcomes assessed include changes after the intervention in: proportion breastfeeding and/or breastfeeding exclusively; incidence of common infant illnesses in the first year of life; and feeding-group specific incidence of illness.
The proportion of women breastfeeding exclusively for any period of time increased from 16.4% to 54.6% after the intervention. The percent of children having pneumonia and gastroenteritis declined 32. 2% and 14.6%, respectively, after the intervention. Feeding-group specific rates of these illnesses were unchanged, indicating that the decline observed was attributable to the increased proportion of infants breastfeeding. In contrast, rates of croup and bronchiolitis increased after the intervention among those fed formula from birth, suggesting a viral epidemic which was limited to those never exclusively breastfed. Finally, sepsis declined in both formula-fed and breastfed infants after the intervention, suggesting that other factors affected this illness outcome after the intervention.
Increasing the proportion of exclusively breastfed infants seems to be an effective means of reducing infant illness at the community level. The experimental design suggests that the increased incidence of illness among minimally breastfed infants is causally related to lack of breast milk, rather than being attributable to confounding.
尽管母乳喂养与多种婴儿疾病的较低发病率相关，但怀疑者认为，即便经过适当的统计调整，这种关联很大程度上仍可归因于混杂因素。本文采用一种新颖的设计，来调查一项成功的母乳喂养促进项目实施后社区层面婴儿疾病的变化情况。
在这项基于人群的队列研究中，回顾了一个纳瓦霍社区在母乳喂养促进项目开展前一年（n = 977）和干预期间（n = 858）出生的所有婴儿的病历。评估的结果包括干预后以下方面的变化：母乳喂养和/或纯母乳喂养的比例；生命第一年常见婴儿疾病的发病率；以及特定喂养组的疾病发病率。
干预后，任何时间段内纯母乳喂养的女性比例从16.4%增至54.6%。干预后，患肺炎和肠胃炎的儿童比例分别下降了32.2%和14.6%。这些疾病在特定喂养组的发病率未变，这表明观察到的发病率下降归因于母乳喂养婴儿比例的增加。相比之下，干预后，出生即喂配方奶的婴儿中哮吼和细支气管炎的发病率上升，这表明存在一场仅限于从未纯母乳喂养婴儿的病毒流行。最后，干预后，配方奶喂养和母乳喂养的婴儿中败血症发病率均下降，这表明干预后其他因素影响了这种疾病的转归。
提高纯母乳喂养婴儿的比例似乎是在社区层面降低婴儿疾病的有效手段。该实验设计表明，极少母乳喂养的婴儿中疾病发病率增加与缺乏母乳存在因果关系，而非归因于混杂因素。
