title: Associations of prenatal maternal blood mercury concentrations with early and mid-childhood blood pressure: a prospective study.
abstract: BACKGROUND
  Childhood blood pressure (BP) is an important determinant of adult cardiovascular disease. Prenatal exposure to methylmercury through maternal fish consumption has been reported to increase the BP of children years later.
  
  
  METHODS
  Mother-child pairs were enrolled from Project Viva, a prospective cohort study in Massachusetts. From second trimester maternal blood samples, we measured erythrocyte mercury concentration. Systolic BP in children, measured up to 5 times per visit in early and mid-childhood (median ages 3.2 and 7.7 years), was the primary outcome. We used mixed-effect regression models to account for variation in the number of BP measurements and to average effects over both time points.
  
  
  RESULTS
  Among 1103 mother-child pairs, mean (SD) second trimester total erythrocyte mercury concentration was 4.0 (3.9)ng/g among mothers whose children were assessed in early childhood and 4.0 (4.0)ng/g for children assessed in mid-childhood. Mean (SD) offspring systolic BP was 92.1 (10.4)mm Hg in early childhood and 94.3 (8.4)mm Hg in mid-childhood. After adjusting for mother and infant characteristics, mean second trimester blood mercury concentration was not associated with child systolic BP (regression coefficient, 0.1mm Hg; 95% CI, -1.3 to 1.5 for quartile 4 vs. quartile 1) at either time period. Further adjusting for second trimester maternal fish consumption, as well as docosahexaenoic acid and eicosapentaenoic acid consumption, did not substantially change the estimates.
  
  
  CONCLUSIONS
  The results of this study demonstrate an absence of association between childhood blood pressure and low-level mercury exposure typical of the general US population.
authors.affiliation: Harvard Medical School, Boston, MA, United States. Electronic address: Brian.kalish@childrens.harvard.edu.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Kalish
authors.affiliation: Obesity Prevention Program, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, United States.
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Rifas-Shiman
authors.affiliation: Channing Laboratory, Brigham and Women׳s Hospital and Harvard Medical School, Boston, MA, United States.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Wright
authors.affiliation: Channing Laboratory, Brigham and Women׳s Hospital and Harvard Medical School, Boston, MA, United States.
authors.forename: Chitra J
authors.initials: CJ
authors.lastname: Amarasiriwardena
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, United States.
authors.forename: Innocent
authors.initials: I
authors.lastname: Jayawardene
authors.affiliation: Obesity Prevention Program, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, United States.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Gillman
authors.affiliation: Department of Pediatrics, Wayne State University School of Medicine and Children׳s Hospital of Michigan, Detroit, MI, United States.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Lipshultz
authors.affiliation: Obesity Prevention Program, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, United States.
authors.forename: Emily
authors.initials: E
authors.lastname: Oken
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005312:Fetal Blood / Q000502:physiology; D006801:Humans; D008297:Male; D018811:Maternal Exposure; D008767:Methylmercury Compounds / Q000097:blood / Q000506:poisoning*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood* / Q000503:physiopathology*; D011446:Prospective Studies
chemical_list: D008767:Methylmercury Compounds
keywords: Blood pressure; Mercury; Prenatal exposure