Effect of hemoglobin adjustment on the precision of mercury concentrations in maternal and cord blood

Abstract

The cord-blood mercury concentration is usually considered the best biomarker in regard to developmental methylmercury neurotoxicity. However, the mercury concentration may be affected by the binding of methylmercury to hemoglobin and perhaps also selenium. As cord-blood mercury analyses appear to be less precise than suggested by laboratory quality data, we studied the interrelationships of mercury concentrations with hemoglobin in paired maternal and cord blood samples from a Faroese birth cohort (N = 514) and the Mothers and Children’s Environmental Health study in Korea (n=797). Linear regression and structural equation model (SEM) analyses were used to ascertain interrelationships between the exposure biomarkers and the possible impact of hemoglobin as well as selenium. Both methods showed a significant dependence of the cord-blood concentration on hemoglobin, also after adjustment for other exposure biomarkers. In the SEM, the cord blood measurement was a less imprecise indicator of the latent methylmercury exposure variable than other exposure biomarkers available, and the maternal hair concentration had the largest imprecision. Adjustment of mercury concentrations both in maternal and cord blood for hemoglobin improved their precision, while no significant effect of the selenium concentration in maternal blood was found. Adjustment of blood-mercury concentrations for hemoglobin is therefore recommended.

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years

“…The Faroese Cohort 5 of 490 children was recruited from births at the National Hospital in Tórshavn, Faroe Islands, during 2007–2009 (Kim et al 2014; Timmermann et al 2017). A maternal serum sample was collected about two weeks after the expected term date.…”

Early-life exposures to persistent organic pollutants in relation to overweight in preschool children

“…A cohort of 490 mother-child pairs was recruited at childbirth, at the National Hospital of the Faroe Islands, during an 18-month period between 2007 and 2009, and followed at child ages 18 months and 5 years (39, 40). The Faroese are a marine population of mainly Scandinavian and Irish origin, with high seafood intakes that contribute to elevated POP exposures (41, 42).…”

Shorter duration of breastfeeding at elevated exposures to perfluoroalkyl substances

“…Two birth cohorts were formed in 1997–2000 [18-20] and in 2007-2009 [21] in the Faroe Islands. Located in the North Atlantic, the Faroe Islands is a self-governing marine community within the Danish kingdom.…”