Influence of increased survival in very low birth weight, low birth weight, and normal birth weight infants on the incidence of sudden infant death syndrome in the United States: 1985-1991.
OBJECTIVE
To examine the relationship between infant survival and the rates sudden infant death syndrome (SIDS) in very low birth weight (VLBW), low birth weight (LBW), and normal birth weight (NBW) infants from 1985 to 1991.


METHODS
The National Center for Health Statistics Birth Cohort Linked Birth/Infant Death Data Sets were used to determine birth weight, age at death, and cause of death for US-born singleton infants with birth weights of 500 g or more.


RESULTS
Increasing infant and postneonatal survival rates were greatest in VLBW infants. In contrast, SIDS rates did not change in VLBW infants (3.66 to 3.69; P = .70) but declined in both LBW (3.51 to 3.32; P = .041) and NBW (1.07 to 1.03; P = .008) infants. Postneonatal SIDS rates (per 1000 neonatal survivors) did not change in VLBW (4.93 to 4.58; P = .58) or LBW (3.36 to 3.22; P = .07) infants but declined in NBW infants (1.00 to 0.97; P = .018). Although there were differences among the slopes of survival rates, there was no statistical evidence of differences in the slope of SIDS rates among the three groups.


CONCLUSIONS
The marked increase in survival of VLBW infants increased the pool of babies at potential risk for SIDS. VLBW infants' SIDS rates have not changed while they have declined in NBW and LBW infants.
Department of Pediatrics, Rush Children's Hospital, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
H R
HR
Bigger
J M
JM
Silvestri
S
S
Shott
D E
DE
Weese-Mayer
D001724:Birth Weight; D006801:Humans; D015994:Incidence; D007226:Infant Mortality / Q000639:trends; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D016015:Logistic Models; D013398:Sudden Infant Death / Q000453:epidemiology*; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology