Polychlorinated biphenyls (PCBs) and neurological development in children: a systematic review

Abstract

Background-Polychlorinated biphenyls (PCBs) are complex mixtures of persistent contaminants that are widespread in the environment. Newborns are exposed across the placenta and through breast feeding. Experimental animal studies have indicated that PCBs are neurotoxic. The neurological eVects of these compounds on children are not clear. Methods-A systematic review of literature on the relation between neurological development in children and exposure to polychlorinated biphenyls. Results-Seven follow up studies evaluated the eVect of prenatal exposure to PCBs. Two of these studies evaluated highly exposed children. In newborns, an increase of the abnormal reflexes was observed in all four studies evaluating it. During the first months of life, a decrease in motor skills was observed in four of the five studies that investigated psychomotor development; deficits in the acquisition of cognitive skills were observed only in one study assessing non-highly exposed populations. At 4 years of age, an eVect on the cognitive areas was observed in four of the five studies that evaluated it. Postnatal exposure to PCBs through breast feeding was not clearly related to any eVect on neurological development. Conclusions-These studies suggest a subtle adverse eVect of prenatal PCBs exposure on child neurodevelopment. Differences in study design, inconsistency in some of the results, and the lack of adequate quantitative exposure data, do not allow the derivation of the degree of risk associated with neurodevelopmental eVects at current levels of exposure. (J Epidemiol Community Health 2001;55:537-546)

Exposição a agrotóxicos e eventos adversos na gravidez no Sul do Brasil, 1996-2000

“…Assim, um aspecto importante do possível efeito dos agrotóxicos consiste no fato de que um aumento dos nascimentos precoces acarrete um incremento na mortalidade infantil 35 . Alguns estudos de coorte em população geral já associaram o nascimento prematuro com a exposição pré-natal ou neonatal a determinados agrotóxicos organoclorados, como o hexaclorobenzeno 11,12 , o dicloro difenil tricloroetano (DDT) e seu metabólito dicloro difenil dicloroetileno (DDE) 10,36,37 , e alguns metabólitos de pesticidas organofosforados 16 . Ao avaliarem 2.380 crianças recém-nascidas, Longnecker et al 10 encontraram um efeito dose-resposta entre a ocorrência de prematuridade e a exposição pré-natal ao DDE.…”

Levels of selected persistent organic pollutants in blood from delivering women in seven selected areas of São Paulo State, Brazil

“…These man-made chemicals are highly resistant to biodegradation and have high affinities for bioaccumulation and biomagnifications, both in environment biota and in living organisms including humans. A number of human studies have shown POP exposure effects on neurological development; thyroid, oestrogen, and immune function; and cancer promotion (Brouwer et al, 1998;Patandin et al, 1999;Porta et al, 2008;Ribas-Fito et al, 2001;Snedeker, 2001;Tryphonas, 1998;Wolff and Toniolo, 1995).…”

Effects of polychlorinated biphenyls on maternal odor conditioning in rat pups

“…Adverse effects include lower birth weights in children, shorter gestational periods, impaired autonomic function, weak reflexes and attentional deficits [1][2][3]15]. Developing fetuses and newborns are the most vulnerable, obtaining more concentrated PCBs from the placenta or from breast milk during suckling [16,17].…”