Exposure to Mercury and Association with Diet at 7 years in the Italian Northern Adriatic Birth Cohort

Background: In 2007 in Trieste (Italy) a prospective mother-child cohort (Italian Northern Adriatic Birth cohort) was established to investigate the association between prenatal Hg exposure from maternal fish consumption and child neurodevelopment. 900 pregnant women were enrolled and children born within the cohort were followed–up until they reached the age of 7 years. The cohort was involved in the “Public health impact of long-term, low-level, mixed element exposure in susceptible population strata” and “Cross-Mediterranean Environment and Health Network” projects. The aim of this research is to study the associations between Hg measured in 7-year-old children’s hair and urine and nutrient intakes. Materials and methods: Participating subjects were 7-year-old children who completed the 3-day-dietary-record and for whom Hg was measured in urine (n=375) and hair (n=232). Nutrients and energy intakes, and percentage contribution to total energy and to protein from fish were computed from 3-day-dietary-record. Median and interquartile-range (IQR) were computed for each nutritional variable and Hg. Associations with log2(Hg) and nutritional variables were explored applying multivariate linear regressions adjusted by children’s gender. Separate models were applied for each log2(Hg) and nutritional variable. Results: Median Hgurine was 0.39 ng/mL (IQR=0.23–0.65) and Hghair was 535.33 ng/g (IQR=291.90–910.27). Log2(Hgurine) and log2(Hghair) were positively associated with %EnFish (βurine=0.07, 95%CI=0.02-0.12; βhair=0.09, 95%CI=0.03–0.15), %ProtFish (βurine=0.02, 95%CI=0.003–0.03; βhair=0.03, 95%CI=0.01–0.05). Log2(Hgurine) and log2(Hghair) were negatively associated with PUFAsω6:ω3 (βurine=-0.05, 95%CI=-0.09– -0.003; βhair=-0.06, 95%CI=-0.12– -0.01). Several nutrients (g/day) and Selenium (μg/day) were positively associated with log2(Hghair): EPA (β=2.22, 95%CI=0.42–4.01), DHA (β=0.91, 95%CI=0.23–1.59), EPA+DHA (β=0.71, 95%CI=0.20–1.23), PUFAs (β=0.10, 95%CI=0.01–0.19), PUFAsω3 (β=0.75, 95%CI=0.33–1.17), linolenic acid (β=1.19, 95%CI=0.29–2.09) and Se (β=0.02, 95%CI=0.01–0.03). Conclusions: At 7 years, in the Italian Northern Adriatic Birth Cohort, mercury was positively associated with nutritional variables linked to fish consumption and negatively associated with PUFAsω6:ω3.