Infant Feeding and Infectious Disease

To the Editor.— I read with interest the article "Relationship Between Infant Feeding and Infectious Illness: A Prospective Study of Infants During the First Year of Life" by Rubin et al in the April issue.1 Two things puzzle me. The first is that, despite the authors' stated goal of paying close attention to methodology, their definition of breast-feeding fails to meet the standards set forth by most experts on lactation. The second is that, given their substantial investment of time and money in obtaining detailed data on 500 babies for a full year, the authors chose to ask their particular research question.