For over 30 years the Seychelles Child Development Study (SCDS) has focused on examining the potential
developmental risks associated with low-level methylmercury (MeHg) exposure stemming from daily ocean fish
consumption during pregnancy, an issue of high public health significance. Our studies of over 3,000
participants have shown that nutrients, genetics, and maternal immune function play an important role. These
findings provide important clues towards better understanding mechanisms of low-level MeHg toxicity and
factors that may influence susceptibility. Our international research consortium includes four key partners with
expertise in toxicology, epidemiology, biostatistics, nutritional biochemistry, and human genetics. The SCDS is
a unique source of longitudinal data with extensive information on biomarkers and population characteristics. It
is imperative that this resource is preserved, thoroughly documented, and enriched to realize its long-term
scientific potential. The proposed study will lay the foundation for continued, integrative and translational
science examining MeHg toxicity mechanisms and the long-term dynamics of low-level MeHg exposure. The
current proposal has three specific aims. First, we will enrich the biorepository and outcomes database of
the NC2 cohort for future studies of underlying mechanisms of MeHg toxicity and clinically-relevant
phenotypes. We will re-examine 1,457 Nutrition Cohort 2 (NC2) participants who were recruited in 2008-2011
and are currently undergoing a 7-year examination. We will obtain hair and blood samples for future studies
focusing on mechanisms of MeHg metabolism and toxicity. We will also collect data on medical history,
sociodemographic factors, anthropometrics measures, health behaviors, and fish consumption, and we will link
our study records with school examination records. Second, we will enrich the biorepository and outcome
database of Main cohort study participants and their mothers to establish baseline data for novel
prospective studies of MeHg toxicity across the life course. We will re-enroll the Main cohort (n=615;
recruited in 1989-1990 and followed for 24 years) and their mothers (n=622, recruited in 1989-1990 and re-
enrolled in 2013) and update data on health behaviors, sociodemographic factors, medical history,
anthropometric measures, and fish consumption. We will collect hair and blood samples, and measure hair
MeHg levels to estimate exposure across 30 years of follow up. In the Main cohort we will examine markers of
autoimmune responses and correlate them with life course MeHg exposure estimates. Mothers will complete a
brief assessment of physical and cognitive functioning. Finally, we will facilitate data access and sharing
through improved data harmonization and discovery. We will develop an online Data Access Request and
Visualization Application that will consist of a standardized data dictionary across all SCDS cohorts. It will allow
users to explore our data through the visualization of descriptive statistics, and to request data and samples.
