0283 Urinary Thallium Concentration and Objective Sleep: An Examination in Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract Introduction Thallium (Tl), a toxic metal abundant in the Earth’s crust, is a neurotoxicant that crosses the blood brain barrier and disrupts potassium-dependent neural communication. Tl’s neurotoxic effects have been linked to sleep disturbance. Prior research on the relationship between Tl and sleep relied on self-reported sleep measures or were isolated to specific populations (e.g., occupational, regional). We examined the relationship between Tl and sleep by analyzing the long-term impacts of Tl exposure on actigraphy- and polysomnography (PSG)-derived sleep outcomes in a large multiethnic cohort across the United States. Methods We used data from Multi-Ethnic Study of Atherosclerosis (MESA). Spot urinary measurements of Tl concentration were measured at Exam 1 (2000-2002) and overnight in-home PSG with seven days of wrist-worn actigraphy were collected between 2010-2013. We employed nonparametric partial correlations to examine the relationship between log-transformed Tl and sleep outcomes, adjusting for demographics, site and urinary creatinine. Results 1822 adults were included (mean age 59.3 (45-84) years, 53.5% female, and 37.5% White, 27.9% Black/African American, 23.3% Hispanic, and 11.2% Chinese). Higher Tl levels were associated with actigraphy-based shorter sleep duration (rs = -.05, p < .05), higher wake after sleep onset (rs = .07, p <.01), shorter sleep maintenance efficiency (rs = -.08, p < .01), and higher activity during sleep (L5, rs = .05, p < .05). In contrast, higher Tl was related to favorable PSG-derived metrics: less %N1 (rs = -.05, p < .05), greater N3 (rs = .06, p < .05), and greater REM duration (rs = .06, p < .05). Higher Tl also was associated with higher sleep regularity (lower sleep duration SD; rs = -.06, p < .01; and Inter-day Stability: rs = .05, p < .05). Conclusion Tl was associated with more fragmented sleep measured at home with actigraphy, but with higher sleep regularity, and deeper sleep by PSG. The discordance of associations across sleep domains may indicate a complex effect of metal exposure and requires further investigation. Such findings may contribute to understanding the potential role of heavy metals on neurological process and sleep. Support (if any) The MESA Sleep studies were supported by NHLBI HL56984 and NIA R01AG070867.