TPS 621: Exposure to metals, Johan Friso Foyer, Floor 1, August 26, 2019, 3:00 PM - 4:30 PM Background: Little is known about the extent of exposure to multiple metals among midlife women. Objectives: We assessed exposure to multiple metals in the Study of Women’s Health Across the Nation (SWAN), a multi-site, multi-ethnic cohort of women at midlife. Methods: We measured urinary concentrations of 21 metals (arsenic, barium, beryllium, cadmium, cobalt, chromium, cesium, copper, mercury, manganese, molybdenum, nickel, lead, platinum, antimony, tin, thallium, uranium, vanadium, tungsten and zinc) using high-resolution inductively coupled plasma-mass spectrometry among 1,335 white, black, Chinese and Japanese women aged 45-56 years at the third SWAN annual visit (1999-2000). Least squared geometric mean concentrations were compared across race/ethnicity, education, financial hardship, smoking, secondhand smoking, sea food intake and rice intake groups. Overall exposure patterns of multiple metals were derived using k-means clustering method. Results: The percentage of women with detectable concentrations of metals ranged from 100% for arsenic, cesium, molybdenum and zinc, to less than 5% for platinum; 15 metals had detection rates of 70% or more. Asian populations, including both Chinese and Japanese women, had higher urinary concentrations of arsenic, cadmium, copper, mercury, molybdenum, lead, thallium, compared with other racial/ethnic groups, independent of sociodemographic, lifestyle, dietary, and geographic characteristics. Seafood and rice intakes were important contributors to arsenic, cesium, mercury, molybdenum and lead uptake. Two distinct overall exposure patterns- “high” vs. “low” -- were identified. Women in the “high” overall exposure pattern were more likely to be Asians, current smokers, and those with high consumption of seafood and rice, while they were less likely to be black. Conclusions: Exposures of midlife women to metals differs by racial/ethnic, sociodemographic, lifestyle, dietary, and geographic characteristics. Asian women may be experiencing the highest exposures to multiple metals compared with other racial/ethnic groups in the United States.