Communities advancing the studies of Tribal nations across their lifespan: Design, methods, and baseline of the CoASTAL cohort.

The CoASTAL cohort represents the first community cohort assembled to study a HAB related illness. It is comprised of three Native American tribes in the Pacific NW for the purpose of studying the health impacts of chronic, low level domoic acid (DA) exposure through razor clam consumption. This cohort is at risk of domoic acid (DA) toxicity by virtue of their geographic location (access to beaches with a history of elevated DA levels in razor clams) and the cultural and traditional significance of razor clams in their diet. In this prospective, longitudinal study, Wave 1 of the cohort is comprised of 678 members across the lifespan with both sexes represented within child, adult and geriatric age groups. All participants are followed annually with standard measures of medical and social history; neuropsychological functions, psychological status, and dietary exposure. DA concentration levels are measured at both public and reservation beaches where razor clams are sourced and multiple metrics have been piloted to further determine exposure. Baseline data indicates that all cognitive and psychological functions are within normal limits. In addition there is considerable variability in razor clam exposure. Therefore, the CoASTAL cohort offers a unique opportunity to investigate the potential health effects of chronic, low level exposure to DA over time.