10 Chronic cadmium exposure is associated with Alzheimer’s Disease-related mortality in adults over age 60 in a representative US sample

Abstract

OBJECTIVES/GOALS: Cadmium is a widespread neurotoxic metal pollutant; however prior study results of Cd and later-life cognition are mixed. We investigated association of urinary cadmium on Alzheimer’s Disease (AD) mortality risk, accounting for key co-pollutants smoking and lead, in the presence of competing risks. METHODS/STUDY POPULATION: We included 5692 persons, 60 years old from the 1998-2018 National Health and Nutrition Examination Survey. Underlying cause of death was determined via linked 1999-2019 National Death Index data. Urinary cadmium (UCD) reflects prolonged exposure and was adjusted for creatinine. We used multiple imputation (5 iterations) to recapture substantial model observation drop-out (N=782). We used three Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence interval (CI) per unit increase in UCD and time to AD mortality: a competing risks model, a survey-weighted model, and a baseline model including neither, all adjusted for demographic characteristics, lead, and smoking. RESULTS/ANTICIPATED RESULTS: Follow-up ranged from 0 to 20.8 years (mean 8.2 years), with a total of 1,987 individuals deceased (14,232 person-years at-risk), including 88 individuals dying from AD. Mean UCD was 0.50 μg/g creatinine (standard error=0.01). In baseline and survey-weighted models fully adjusted for NHANES cycle, poverty income ratio, age, race/ethnicity, sex, marital status, education, smoking status, and blood lead levels, a per unit increase in UCD was associated with approximately twice the rate of AD mortality (baseline model HR: 1.92, 95% CI: 1.28, 2.89; survey-weighted model HR: 2.08, 95% CI: 1.42, 3.06). In the competing risks model, this association was attenuated (HR: 1.58, 95% CI 1.06 2.36). DISCUSSION/SIGNIFICANCE: Our study finds chronic cadmium exposure associated with AD mortality even after accounting for competing risks of AD mortality and confounding effects of cigarette smoking and lead exposure, strengthening the evidence that long-term cadmium exposure adversely affects later-life cognitive health.