Adult hemoglobin levels at birth and risk of sudden infant death syndrome.
BACKGROUND
During the final weeks of gestation, infants normally begin a transition from the production of fetal to adult hemoglobin. Delayed or faulty transition to the production of adult hemoglobin might play a role in the etiology of sudden infant death syndrome (SIDS).


OBJECTIVE
To examine the association between adult hemoglobin levels measured at birth and the subsequent risk of SIDS.


METHODS
Cohort study of all infants born in California between March 1, 1990, and December 31, 1997, who were enrolled in the state's Newborn Screening Program and followed up during the first year of life to identify deaths attributed to SIDS.


METHODS
Population-based sample of 3.2 million infants.


METHODS
Risk of death attributed to SIDS.


RESULTS
The study included 2425 infants whose deaths were attributed to SIDS. There was an inverse relationship between adult hemoglobin level, expressed as a percentage of total hemoglobin, and the subsequent incidence of SIDS. After adjustment for infant sex, race/ethnicity, length of gestation, maternal age, maternal education, maternal smoking, intrauterine growth restriction, and preeclampsia/eclampsia, the relative risks of SIDS for infants in the lower 4 quintiles of adult hemoglobin level were, in descending order, 1.12 (95% confidence interval [CI], 0.96-1.32), 1.38 (95% CI, 1.19-1.59), 1.55 (95% CI, 1.34-1.80), and 2.15 (95% CI, 1.87-2.47) compared with infants in the highest quintile.


CONCLUSIONS
These findings suggest that infants with low levels of adult hemoglobin in the first hours after birth are at elevated risk of SIDS. Delayed maturation in production of adult hemoglobin may play a role in the etiology of some SIDS cases.
Richardson
David B
DB
Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-8050, USA. david_richardson@unc.edu
Wing
Steve
S
Lorey
Fred
F
Hertz-Picciotto
Irva
I
D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D012307:Risk Factors; D013398:Sudden Infant Death / Q000097:blood* / Q000453:epidemiology
D005319:Fetal Hemoglobin