Iben Have Beck

Prenatal and early life PFAA exposure; impact on neurodevelopment in 1.5- to 7-year-old children in Odense Child Cohort

 

Background

Perfluoroalkyl acids (PFAAs) are persistent chemicals with water and oil repellent properties thus widely used in in the industrial and commercial production of fabrics, non-stick coatings and grease proof materials. Humans are exposed to these substances in everyday life through ingestion of contaminated drinking water and food and through inhalation of indoor air particles. PFAAs can cross the placenta and expose the developing foetus.

Especially the foetal brain is vulnerable to PFAA exposure, due to its rapid growth and complexity. Exposure to PFAA during this critical time window and in early childhood may have long term impact on neurodevelopment in children. Some studies suggest that prenatal PFAA exposure adversely affect neurodevelopment including language development, motor skills and IQ-scores, whereas other could not confirm these findings. Few studies have included information of childhood PFAA exposure.

Preliminary findings from Odense Child cohort suggest that prenatal exposure to perfluorooctane sulfonic acid (PFOS) is associated with reduced vocabulary score at age 18 months in boys. These sex specific findings are of concern as language development is a marker of later school performance. It is therefore important to investigate whether these adverse effects are persisting.

Aim

In Odense Child Cohort (OCC) I will investigate the impact of prenatal and early life (age 18 months) exposure to PFAAs on neurodevelopment including:

1. Language development in children aged 18 to 36 months.

2. Motor skills in 7-year-old children.

3. IQ-score in 7-year-old children.

Method

In the OCC women living in the municipality of Odense, who were pregnant between 2010 and 2012, were invited to participate in gestational weeks 8-16. At the time of inclusion, a blood sample was drawn, and the participants filled in a questionnaire on general health, lifestyle and social factors. At birth and at 3, 18, 36 and 60 months of age, questionnaires on child and parent’s health were filled in and the child underwent a clinical xamination including anthropometric measurements. Currently, there are around 2500 active mother-child pairs in the OCC. PFAAs has been measured in approximately 1600 mothers at gestational age 8-16 weeks and is currently being measured in 900 children at age 18 months.

Neurodevelopment will be assessed from age 18 months to 7 years by a panel of tests;

1) language development derived from an electronic version of the internationally validated MacArthur-Bates Communicative Development Inventories (MB-CDI) parent rapport filled in by parents every third month from child age 18 to 36 months.

2) motor skills are assessed by multiple motoric tests obtained at age 7 years e.g. handgrip- and trunk muscle strength and assessment of gross- and fine-motor skills.

3) internationally validated IQ test (WISC-V) standardized to Danish children, assessed in all children when entering school.

I will use relevant statistical analyses to investigate the associations between exposure and outcomes presented above, and adjust for relevant covariates e.g. maternal; age, educational level, BMI, parity, medicine intake, diet, alcohol consumption, smoking, stress, infections, thyroid stimulating hormone and free thyroxine and child; birthweight, head circumference, prematurity, duration of breastfeeding, diet, stimulation and attachment.

Perspectives

The topic is important, and the timing is right, as the European Union (EU) has highlighted the lack of data on PFAA. Findings of association between prenatal exposure to PFAA and days with fever in toddlers from the OCC have been used by the European Food Safety Authority (EFSA) in lowering the established levels of tolerable daily intake considerably.

If associations between exposure to PFAA and neuropsychological development are found, it may be considered for possible targets for intervention, as lost IQ points caused by exposure to chemicals has in the EU been estimated to cost billions of Euros. The findings will be published in high impact journals and used to inform the public as well as to interact and collaborate with advisory authorities to reduce exposure to these chemicals.