Association between proximity to a lead releasing facility and cognition in diverse cohorts

Background While lead exposure is associated with poorer cognitive performance in children, the association with late life cognition in diverse cohorts is unknown.

In two adult cohorts (Kaiser Health Aging and Diverse Life Experiences (KHANDLE, n=1,638), Study of Healthy Aging in African Americans (STAR, n=741)), we assessed residential proximity to lead releasing facilities, measured through the Toxics Release Inventory, for associations with domain-specific cognition, measured using the Spanish and English Neuropsychological Assessment Scales, two years later. Linear regression models were adjusted for age, sex, race/ethnicity (KHANDLE only), income, education, marital status, smoking status, and alcohol consumption. We meta-analyzed across cohorts.

The average age at cognitive test was 76.1 years (KHANDLE) and 68.8 years (STAR) and the average distance between residence and lead releasing facility was 8.2 km (KHANDLE) and 3.6 km (STAR). In meta-analysis, for every 5 km closer a residential address was located to a lead releasing facility we observed −0.05 standard deviation lower verbal episodic memory (95% CI: −0.08, −0.02). Living within a 3 km buffer of a lead releasing facility was associated with −0.10 lower semantic memory (95% CI: −0.18, −0.02) and −0.08 lower global cognition (95% CI: –0.14, −0.02).

Residential proximity to a lead releasing facility was associated with poorer cognition two years later among adults in two cohorts. Comprehensive understanding of environmental factors is critical for dementia prevention. Competing Interest Statement The authors have declared no competing interest. Funding Statement The Kaiser Health Aging and Diverse Life Experiences and the Study of Healthy Aging in African Americans are supported by the National Institute on Aging (RF1AG052132, RF1AG050782). This analysis was supported by the National Institute on Aging (R01AG074347 and R01-1AG067525). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The institutional review board at Kaiser Permanente Northern California approved both cohort studies (1278966, 1279068) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data availability All lead exposure data used for this analysis are publicly available and can be downloaded from the EPA TRI Toxics Tracker webpage at https://edap.epa.gov/public/extensions/TRIToxicsTracker/TRIToxicsTracker.html. For access to participant data used in this analysis, please contact the senior author, Kathryn Conlon, kcconlon{at}health.ucdavis.edu.