title: Prenatal exposure to mercury and fish consumption during pregnancy and attention-deficit/hyperactivity disorder-related behavior in children.
abstract: OBJECTIVE
  To investigate the association of prenatal mercury exposure and fish intake with attention-deficit/hyperactivity disorder (ADHD)-related behavior.
  
  
  METHODS
  For a population-based prospective birth cohort recruited in New Bedford, Massachusetts (1993-1998), we analyzed data for children examined at age 8 years with peripartum maternal hair mercury measures (n = 421) or maternal report of fish consumption during pregnancy (n = 515). Inattentive and impulsive/hyperactive behaviors were assessed using a teacher rating scale and neuropsychological testing.
  
  
  RESULTS
  The median maternal hair mercury level was 0.45 μg/g (range, 0.03-5.14 μg/g), and 52% of mothers consumed more than 2 fish servings weekly. In multivariable regression models, mercury exposure was associated with inattention and impulsivity/hyperactivity; some outcomes had an apparent threshold with associations at 1 μg/g or greater of mercury. For example, at 1 μg/g or greater, the adjusted risk ratios for mild/markedly atypical inattentive and impulsive/hyperactive behaviors were 1.4 (95% CI, 1.0-1.8) and 1.7 (95% CI, 1.2-2.4), respectively, for an interquartile range (0.5 μg/g) mercury increase; there was no confounding by fish consumption. For neuropsychological assessments, mercury and behavior associations were detected primarily for boys. There was a protective association for fish consumption (>2 servings per week) with ADHD-related behaviors, particularly impulsive/hyperactive behaviors (relative risk = 0.4; 95% CI, 0.2-0.6).
  
  
  CONCLUSIONS
  Low-level prenatal mercury exposure is associated with a greater risk of ADHD-related behaviors, and fish consumption during pregnancy is protective of these behaviors. These findings underscore the difficulties of balancing the benefits of fish intake with the detriments of low-level mercury exposure in developing dietary recommendations in pregnancy.
authors.affiliation: Department of Environmental Health, Boston University School of Public Health, Boston, Massachusetts 02118, USA. sagiv@bu.edu
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Sagiv
authors.forename: Sally W
authors.initials: SW
authors.lastname: Thurston
authors.forename: David C
authors.initials: DC
authors.lastname: Bellinger
authors.forename: Chitra
authors.initials: C
authors.lastname: Amarasiriwardena
authors.forename: Susan A
authors.initials: SA
authors.lastname: Korrick
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D002648:Child; D004032:Diet / Q000009:adverse effects; D004034:Diet Surveys; D005260:Female; D005506:Food Contamination; D006197:Hair / Q000737:chemistry; D006801:Humans; D016014:Linear Models; D008297:Male; D008404:Massachusetts; D018811:Maternal Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D008628:Mercury / Q000032:analysis / Q000633:toxicity*; D015999:Multivariate Analysis; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced* / Q000175:diagnosis / Q000517:prevention & control; D039401:Prenatal Nutritional Physiological Phenomena; D011446:Prospective Studies; D011581:Psychological Tests; D017747:Seafood / Q000009:adverse effects; D011795:Surveys and Questionnaires; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D055815:Young Adult
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury