Effects of breast feeding on neuropsychological development in a community with methylmercury exposure from seafood

Abstract

Breastfeeding has been associated with an advantage to infant neurobehavioral development, possibly in part due to essential nutrients in breast milk. However, breast milk may be contaminated by environmental neurotoxicants, such as methylmercury. In the Faroe Islands, where maternal consumption of pilot whale may cause transfer of marine toxicants into breast milk, a cohort of 1022 consecutive singleton births was generated during 1986-87. Methylmercury exposure was assessed from mercury concentrations in cord blood and in the hair of the child at age 12 months, and the duration of breastfeeding was recorded. At approximately 7 years of age, 917 (90%) of the children underwent detailed neurobehavioral examination. After adjustment for confounders, breastfeeding was associated with only marginally better neuropsychological performance on most tests. These associations were robust even after adjustment for cord-blood and hair mercury concentration at age 1 year. Thus, in this cohort of children with a relatively high prenatal toxicant exposure and potential exposure to neurotoxicants through breast milk, breastfeeding was associated with less benefits on neurobehavioral development than previously published studies though not associated with a deficit in neuropsychological performance at age 7. Although the advantage may be less, Faroese women can still safely breastfeed their children.

Fishing activity, health characteristics and mercury exposure of Amerindian women living alongside the Beni River (Amazonian Bolivia)

“…In the past, studies advised against breast feeding for a long period in fishing communities (Grandjean et al, 1994). At present, the benefits of breast feeding in terms of the neurodevelopment of children living in stressful environments are generally considered to outweigh the risks of mercury poisoning (Jensen et al, 2005, Marques et al, 2009. However, in this study, women breast-fed their children for a long time (mean age of weaning: 16.8 ± 6.5 months (Beneficeet al, 2006)), and could be an issue.…”

A Metalloproteomics Study on the Association of Mercury With Breast Milk in Samples From Lactating Women in the Amazon Region of Brazil

“…The concentrations of Hg recorded in the hair of contaminated children are significantly greater after the age of 12 months. The relationship between the decreased early development of these children and the high levels of Hg in the infants' hair appears to be associated with breastfeeding because no other source of contamination has been detected (Yang et al 1997;Gundacker et al 2002;Jensen et al 2005).…”

Cord Blood Mercury and Early Child Development: Effects of the World Trade Center

“…However, the additional EtHg exposure from postnatal TCV may contribute to a relative increase in infant hair-Hg (Marques et al 2007). Coupled with that, the Faroese cohort studies (Grandjean et al 1995; Jensen et al 2005) cited by (Lederman et al 2008) to demonstrate prenatal MeHg effects on neurobehavior have also noted the positive and confounding effects of breast-feeding.…”