Incorrect Outcome Variable

To the Editor .— Forste et al1 conclude that increases in breastfeeding among black women would narrow the gap between black and white infant mortality. They have incorrectly identified their outcome variable and reached conclusions not supported by their research. This is not a study of infant mortality (deaths in the first year of life). By excluding infant deaths in the first month of life, they have studied something akin to postneonatal mortality (deaths after day 27). High black infant mortality is largely caused by the increased incidence of preterm delivery in black women (compared with white women). Most infant mortality among black preterm babies occurs in the first 27 days. In addition, the authors have provided no …