Risk factors for lower respiratory tract infection death among infants in the United States, 1999-2004.

OBJECTIVE: To describe maternal and birth-related risk factors associated with lower respiratory tract infection (LRTI) deaths among infants.
METHODS: Records for infants with LRTI as a cause of death were examined by using the linked birth/infant death database for 1999-2004. Singleton infants dying with LRTI and a random sample of surviving singleton infants were compared for selected characteristics.
RESULTS: A total of 5420 LRTI-associated infant deaths were documented in the United States during 1999-2004, for an LRTI-associated infant mortality rate of 22.3 per 100,000 live births. Rates varied according to race; the rate for American Indian/Alaska Native (AI/AN) infants was highest (53.2), followed by black (44.1), white (18.7), and Asian/Pacific Islander infants (12.3). Singleton infants with low birth weight (<2500 g) were at increased risk of dying with LRTI after controlling for other characteristics, especially black infants. Both AI/AN and black infants born with a birth weight of > or =2500 g were more likely to have died with LRTI than other infants of the same birth weight. Other risk factors associated with LRTI infant death included male gender, the third or more live birth, an Apgar score of <8, unmarried mother, mother with <12 years of education, mother <25 years of age, and mother using tobacco during pregnancy.
CONCLUSIONS: Low birth weight was associated with markedly increased risk for LRTI-associated death among all of the racial groups. Among infants with a birth weight of > or =2500 g, AI/AN and black infants were at higher risk of LRTI-associated death, even after controlling for maternal and birth-related factors. Additional studies and strategies should focus on the prevention of maternal and birth-related risk factors for postneonatal LRTI and on identifying additional risk factors that contribute to elevated mortality among AI/AN and black infants.