Recurrence risk of neonatal hyperbilirubinemia in siblings
M. J. Khoury, E. E. Calle and R. M. Joesoef
Division of Birth Defects and Developmental Disabilities, Centers for Disease Control, Atlanta, GA 30333.
The recurrence of neonatal hyperbilirubinemia (NHB) in full siblings was
studied in 3301 live infants born between 1966 and 1986 to 1669 male US
Army veterans who were part of a nationwide health study. The study
population included 580 sibships with one infant, 679 with two, and 410
with three or more. Hospital of birth medical records were abstracted on
these children. Neonatal hyperbilirubinemia was defined as present if the
recorded peak bilirubin level was greater than 205 mumol/L in the absence
of hemolytic disease of the newborn. The risk of NHB in newborns who have
one or more prior sibs with NHB was 3.1 times higher than that of newborns
who have prior sibs without NHB (10.3% vs 3.6%). Simultaneous adjustment
for risk factors for NHB, such as feeding patterns, year of birth, maternal
obstetric events, and infant health variables, did not explain the excess
risk of NHB in sibs. Moreover, the risk of severe NHB (peak bilirubin
level, greater than 257 mumol/L) in newborns who have one or more prior
sibs with severe NHB was 12.5 times higher than that of newborns who have
prior sibs without severe NHB (10.5% vs 0.9%). Separate analyses in
sibships where all sibs were breast-fed and in sibships where all sibs were
bottle-fed gave similar results. These data clearly suggest the familial
nature of NHB. The higher risk of recurrence of NHB in sibs does not seem
to be due to known environmental risk factors for NHB.
