Increased incidence of neonatal hyperbilirubinemia at 3,100 m in Colorado
L. G. Moore, M. A. Newberry, G. M. Freeby and L. S. Crnic
The incidence of neonatal hyperbilirubinemia (defined as total serum
bilirubin levels greater than 12 mg/dL) in all infants born in a 14-month
period at 3,100 m of altitude (32.7%) was more than twice that in infants
born at 1,600 m of altitude (13.0%) and four times the incidence reported
in the literature for sea level. A systematic comparison of factors known
to influence serum bilirubin levels between 150 infants at 3,100 m and 378
infants at 1,600 m failed to disclose any factor(s) other than altitude
that could account for the increased incidence of hyperbilirubinemia at
high altitude. The mechanism responsible for this phenomenon is unknown,
but we speculate that it may involve an adverse influence of high altitude
on bilirubin load, conjugation, and/or uptake in neonatal life.
