Associations among Autoantibodies, Total Blood Mercury, Fish Consumption and Proximity to High-concentration Sediment Arsenic Deposits in Cheyenne River Sioux Tribe Members

摘要

Mercury (Hg) is a ubiquitous toxicant throughout Cheyenne River Sioux Tribe (CRST) lands, and CRST members may be exposed to Hg through fish consumption (FC), which remains an important component of native culture and may supplement household subsistence. Arsenic (As) is also a concern due to the recent identification of high-concentration sediment deposits on CRST lands. Limited data exist in humans, but Hg is an immunotoxicant shown to induce autoimmune disease in rodents. As has been found to both suppress and stimulate the immune system in humans. The goals of this pilot study were to 1) ascertain whether total blood Hg levels (THg) reflect Hg exposure through FC and smoking, and 2) determine whether THg, FC and distance from As deposits associate with the presence of antinuclear antibodies (ANA) and specific auto-antibodies (sAuAb). During peak fishing season, we recruited 75 participants who regularly consume fish from CRST waters. Hg exposure through FC and smoking were assessed via two questionnaires. Whole blood samples were collected from all participants, and THg was measured using ICP-MS. Participant residence proximity to high-concentration As sites was used as a surrogate for As exposure. We measured ANA and sAuAb in serum and modeled them using demographic and exposure information as predictors. While female gender, age and FC were significant predictors of THg, self-reported smoking was not. 30.7% of participants tested positive for ANA at 2 2+; ANA significantly associated with gender and proximity to As. Female gender, age and FC were significantly associated with the number of elevated sAuAb. Although FC resulted in detectable body burden of Hg, THg alone did not correlate with the presence of ANA or sAuAb in this population. We are currently designing future studies to address CRST health concerns and further investigate the relationships among FC, environmental metal exposures and autoantibodies.