title: Tagum study II: follow-up study at two years of age after prenatal exposure to mercury.
abstract: OBJECTIVE
  To correlate the presence and levels of total mercury (THg) in cord blood and meconium indicating prenatal exposure with developmental milestones at 2 years and to compare these subjects with controls of comparable age using cognitive adaptive test and clinical linguistic auditory milestone scale (CAT/CLAMS).
  
  
  METHODS
  In 48 of the original Tagum (T) subjects, cord blood and meconium Hg levels, head circumference (HC) at birth, and duration of breastfeeding were correlated with CAT/CLAMS at 2 years. At 2 years, THg levels using cold atomic vapor absorption spectrometry were determined in the hair of 46 T subjects and 88 Saranggani (S) controls; THg levels in blood were tested in 48 T subjects and 45 S controls. These levels were correlated with CAT/CLAMS. Both groups had standard physical and neurologic examinations, hearing screen using transitory evoked otoacoustic emissions, serum glutamate pyruvate transaminase, and routine urinalysis. A prevalidated Socioeconomic Means Test was given to both groups.
  
  
  RESULTS
  The Hg level in cord blood was negatively correlated with CAT/CLAMS at 2 years. The HC at birth was negatively correlated with levels of Hg in hair of T subjects 2 years later. HC at birth and 2 years hence were positively correlated with CAT/CLAMS. The following were significantly higher in S controls than in T subjects: expressive language quotient 82.569 +/- 2.21 versus 71.57 +/- 2.61; CLAMS 87.96 +/- 2.43 versus 77.67 +/- 2.51; CAT 90.57 +/- 2.22 versus 83.15 +/- 1.43; and full-scale developmental quotient 89.31 +/- 2.14 versus 80.56 +/- 1.86. Fifteen percent of T subjects had global delay (full-scale developmental quotient <or=70) versus 5.48% in S controls. Hg levels in hair and blood in both T subjects and S controls at 2 years showed no correlation with CAT/CLAMS. The duration of breastfeeding in both groups likewise showed no correlations with CAT/CLAMS.
  
  
  CONCLUSIONS
  The study suggests that prenatal Hg exposure is correlated with lower scores in neurodevelopmental screening, but more so in the linguistic pathway. Other confounding factors cannot be eliminated.
authors.affiliation: Research Development Office, Philippine Children's Medical Center, Quezon City, Philippines. rdo@hiss.pcmc.org.ph
authors.forename: Gloria B
authors.initials: GB
authors.lastname: Ramirez
authors.forename: Olive
authors.initials: O
authors.lastname: Pagulayan
authors.forename: Hirokatsu
authors.initials: H
authors.lastname: Akagi
authors.forename: Ana
authors.initials: A
authors.lastname: Francisco Rivera
authors.forename: Lillian V
authors.initials: LV
authors.lastname: Lee
authors.forename: Anna
authors.initials: A
authors.lastname: Berroya
authors.forename: Ma Cristina
authors.initials: MC
authors.lastname: Vince Cruz
authors.forename: Dainah
authors.initials: D
authors.lastname: Casintahan
mesh_terms: D002675:Child, Preschool; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018811:Maternal Exposure; D008431:Maternal-Fetal Exchange; D008470:Meconium / Q000737:chemistry*; D008628:Mercury / Q000032:analysis* / Q000097:blood*; D011247:Pregnancy / Q000097:blood*; D011297:Prenatal Exposure Delayed Effects
chemical_list: D008628:Mercury