engleski

The association of mercury, fish consumption and child development in a Mediterranean cohort

The effects of prenatal mercury exposure through fish consumption on neurodevelopment have been studied in several populations. Yet, findings have been inconsistent, particularly when assessing the effects of exposure to low mercury levels. To assess the effect of low-level prenatal mercury exposure through fish consumption on neurodevelopment among residents in Mediterranean regions of Italy, Slovenia, Croatia and Greece, we conducted a prospective cohort study within PHIME, a research project of EU Sixth Framework. Main exposures were total mercury (THg) and methylmercury (MeHg) concentration in mother’s hair in pregnancy and in cord blood, and mother’s fish intake in pregnancy. Child’s neurodevelopmental outcomes were Bayley III composite cognitive, language, and motor scores at 18 months. Covariates included pregnancy history, socioeconomic status, child characteristics, breastfeeding, childcare, etc. Data were analyzed with multivariate linear regression. 2189 mothers were enrolled in the study during pregnancy. 1729 mother-child pairs provided information at child’s birth. Follow-up at 18 months was 85%. The distribution of mother’s hair THg (ng/g) was: mean 1023, median 729, 25pct 396, 75pct 1270, mean ratio MeHg/THg 0.90. Cord blood THg (ng/g) was: mean 5.39, median 3.75, 25pct 1.87, 75pct 6.87, mean ratio MeHg/ THg 0.91. Spearman’s correlation between THg in hair and cord blood was: r=0.81, p<0.0001. Mother’s consumption of fish (weekly servings of 150g) was: mean 1.76, median 1.38, 25pct 0.92, 75pct 2.11. While unadjusted models showed a negative association of Bayley cognitive score with THg (in both hair and cord blood) and no association with fish consumption, after adjustment for country and relevant covariates, Bayley cognitive score was no longer associated with THg but positively associated with fi sh (b=0.8345, p=0.0162). Bayley language score was positively associated with fish consumption in both unadjusted and adjusted models but not associated with THg. Bayley motor score was negatively associated with THg only in unadjusted models. In conclusion, in models adjusted for country and other potential confounders, Hg in hair and cord blood did not decrease Bayley scores and a moderate but significant beneficial effect of fi sh consumption in pregnancy was observed for cognitive and language development. Polyunsaturated fatty acids (PUFAs) analyses in mother’s serum will evaluate whether the effect of fish is mediated by PUFAs contained.

mercury; fish consumption; child development; Mediterranean

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