| Abstract Title: | Postnatal MeHg Exposure and Neurodevelopment in the Seychelles Child Development Study Main Cohort |
| Presenter Name: | Edwin van Wijngaarden |
| Company/Institution: | University of Rochester |
| Session: | Progress in understanding Hg and human health impacts |
| Day and Session: | Tuesday 26th July - Session Two |
| Start Time: | 10:00 UTC |
| Co-Authors: | Edwin van Wijngaarden,Sally Thurston |
Abstract Information :
PURPOSE: We investigated postnatal MeHg exposure in relation to neurodevelopment across 24 years of follow-up.
METHODS: We examined 85 neurodevelopmental outcomes measured from ages 9 to 24 years in the Seychelles Child Development Study Main Cohort (n=312-550). Postnatal MeHg exposure measured in the first cm of participants? hair samples collected at seven evaluations were used to create two time-weighted (TW) average MeHg exposure metrics, one for childhood (TW-C) and the other for early adulthood (TW-A). TW-C was based on Hg measures at three ages between 6 months and 5.5 years, and TW-A was based on Hg measured at up to four ages between 17 and 24 years. We examined the association between each metric and neurodevelopmental outcomes using multiple linear regression.
RESULTS: Both TW-C (slope=-0.28; p=0.021) and TW-A (slope=-0.22; p=0.007) metrics were associated with decreased performance on the 22 year Boston Naming Test. TW-C was also associated with greater Continuous Performance Task risk scores (slope=0.75; p=0.014) at 9 years, decreased Bender errors at 10.5 years (slope=-0.235, p=0.029), and increased scores on the 24-year Test of Variables of Attention (TOVA) auditory response time variability (slope=0.014; p=0.049), TOVA visual response time mean (slope=0.006; p=0.049) and TOVA response time variability (slope-0.015; p=0.011), each on the logarithmic scale. At 17 years, TW-A was associated with decreased performance on the Wisconsin Card Sorting Test percent total errors (slope=0.53; p=0.048), the Woodcock-Johnson Passage Comprehension (slope=-0.42; p=0.032), and the CANTAB Rapid Visual Information Processing false alarms (slope=0.017; p=0.026). TW-A was also adversely associated with two measures of executive function at 22 years [CANTAB Intra-Extra Dimensional Shift total errors (slope=0.02; p=0.007) and trials (slope=0.011; p=0.005)]. All associations except with the 10.5-year Bender errors were in the adverse direction.
CONCLUSION: These findings suggest that postnatal MeHg exposure may be adversely associated with neurodevelopmental outcomes in early adulthood.
