Childhood Fish Consumption and Learning and Behavioral Disorders

Abstract

Fish is a major source of nutrients critical for brain development during early life. The importance of childhood fish consumption is supported by several studies reporting associations of n-3 polyunsaturated fatty acid (n-3 PUFA) supplementation with better behavior and school performance. However, fish may have a different effect than n-3 PUFA alone due to the neurotoxic effects of methylmercury, a frequent contaminant. We investigated associations of childhood fish consumption with learning and behavioral disorders in birth cohort study of the neurotoxic effects of early life exposure to solvent-contaminated drinking water. Childhood (age 7-12 years) fish consumption and learning and behavioral problems were reported in self-administered questionnaires (age 23-41 at questionnaire completion). Fish consumption was not meaningfully associated with repeating a grade, tutoring, attending summer school, special class placement, or low educational attainment. However, participants who ate fish several times a week had an elevated odds of Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder (odds ratio: 5.2; 95% confidence interval: 1.5-18) compared to participants who did not eat fish. While these findings generally support the safety of the observed level of fish consumption, the absence of a beneficial effect may be attributed to insufficient fish intake or the choice of relatively low n-3 PUFA fish.

Keywords: ADD; ADHD; fish; learning disorders; methylmercury.

Figure 1

Multivariable ^a GEE odds ratios for associations of childhood (ages 7–12 years) fish consumption with learning and behavioral problems according to frequency of high-mercury fish ^b consumption. Participants who reported no childhood fish consumption (N = 122) were considered the reference. ^a Models adjusted for maternal age at birth (≤21, 22–25, 26–29, ≥30 years), maternal education at time of birth (high school diploma or less, some college, 4-year college grad or higher), and participant race (white, other), sex, year of birth (1969–1974, 1975–1980, 1981–1983), and combined gestational age/birthweight (preterm or <2500 g, term and ≥2500 g); ^b Including fresh tuna, swordfish, bluefish, and freshwater bass. Abbreviations: ADD: attention deficit disorder; ADHD, attention deficit hyperactivity disorder; CI, confidence interval; GEE, generalized estimating equation; OR, odds ratio.