Prenatal Exposure to Mercury and Fish Consumption During Pregnancy and Attention-Deficit/Hyperactivity Disorder–Related Behavior in Children Prenatal Exposure to Mercury

Sagiv SK, Thurston SW, Bellinger DC, et al. — Sat, 01 Dec 2012 00:00:00 GMT

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.

Attention-Deficit/Hyperactivity Disorder A Preventable Epidemic? ADHD

Lanphear BP. — Sat, 01 Dec 2012 00:00:00 GMT

Attention-deficit/hyperactivity disorder (ADHD), one of the most common brain disorders of childhood, affects about 1 in 10 children in the United States. Attention-deficit/hyperactivity disorder is not a specific disorder but a medley of maladaptive behaviors, the most prominent of which are hyperactivity, impulsivity, and inattention. Children who have ADHD often have other coexisting problems, such as aggressive behavior or anxiety; about 1 in 2 children have a learning disorder.

JAMA Pediatrics: Neurotoxicology Topic Collection

Prenatal Exposure to Mercury and Fish Consumption During Pregnancy and Attention-Deficit/Hyperactivity Disorder–Related Behavior in Children Prenatal Exposure to Mercury

Attention-Deficit/Hyperactivity Disorder A Preventable Epidemic? ADHD