Increased Incidence of Neonatal Hyperbilirubinemia at 3,100 m in Colorado

Abstract

• The incidence of neonatal hyperbilirubinemia (defined as total serum bilirubin levels >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. (AJDC 1984;138:157-161)