Lead Exposures and Psychological Symptoms

Abstract

OPS 40: Metals: neurological effects, Room 412, Floor 4, August 28, 2019, 10:30 AM - 12:00 PM Background: Lead exposures have been associated with worse psychological symptoms in adults. Uric acid (UA) has potent antioxidant properties that could modify effects of exposures like lead. We evaluated whether UA modified the association between lead exposures and psychological symptoms. Methods: Biomarker measures of lead in bone (cumulative exposure) and blood (recent exposure) and psychological assessments were available for 793 men in the Normative Aging Study in 1991-2002. Self-reported psychological symptoms were evaluated with the Brief Symptom Inventory (BSI). We assessed global indices of distress and dimensions previously associated with lead exposures: global severity index (GSI), positive symptom total (PST), positive symptom distress index, anxiety, phobic anxiety, depression, somatization, and hostility, with responses greater than one standard deviation above the mean considered as high symptoms. Up to three BSI assessments were considered in repeated measures generalized estimating equations with lead biomarkers, UA, and their interaction, adjusted for age, education, smoking status, cumulative smoking, white collar job, marital status, alcohol intake, and serum creatinine, all assessed at baseline. Results: Participants were 68.0 (SD: 7.0) years old, and proportion of high symptoms ranged from 7.3% (phobic anxiety) to 14.9% (PST), at the baseline BSI assessment. Interactions between patella lead and UA were significant for all global indices and dimensions except hostility. Odds ratio for high GSI for an interquartile (20 µg/g) increase in patella bone lead was 1.36 (1.01-1.84) at the 25th percentile of UA and 1.00 (0.73-1.36) at the 75th percentile of UA. Interactions between tibia bone lead or blood lead and UA were not significant. Conclusions: UA modified the adverse association between patella bone lead and psychological symptoms such that the association was less pronounced at higher levels of UA. These results suggest that strategies involving antioxidants could potentially mitigate the detrimental effects of past lead exposures on psychological symptoms.