Risk factors for infectious disease death among infants in the United States.

BACKGROUND Infectious diseases (IDs) are an important cause of infant mortality in the United States. This study describes maternal and infant characteristics associated with infant ID deaths in the United States. METHODS Infant deaths with an ID underlying cause of death occurring in the United States were examined using the 2008-2009 Period Linked Birth/Infant Death public use data files. Average annual ID infant mortality rates for singleton infants were calculated. A retrospective case-control study was conducted to determine infant and maternal risk factors for infant ID death among low (LBW) and normal (NBW) birth weight groups. Controls were defined as infants surviving to the end of their birth year. Risk factors for infant ID deaths were determined through multivariable logistic regression. RESULTS An estimated 3843 infant ID deaths occurred in the United States during 2008-2009, an overall ID infant mortality rate of 47.5 deaths per 100,000 live births. The mortality rate for LBW and NBW infants were 514.8 and 15.5, respectively. Male sex, younger maternal age (<25 years), a live birth order of fourth or more and low 5-minute Apgar score were associated with increased ID death among LBW and NBW infants. Additionally, black maternal race was associated with increased ID death among LBW infants, and having an unmarried mother was associated with increased ID death among NBW infants. CONCLUSIONS Awareness of associations with infant ID death should help in development of further strategic measures to reduce infant ID morbidity and mortality.