Health effects among a cohort exposed to low-level arsenic in a geothermal area of Tuscany, Italy

Background: Studies on low-level As exposure have not found an association with cancer, while increased risks were reported for skin lesions, respiratory and cardiovascular diseases and reproductive outcomes. Prospective observational studies with individual exposure measures are needed to study low-level As exposure effects. In a geothermal area in Southern Tuscany (Italy), characterized by a natural presence of As in drinking water (< 50 µg/l), As urinary concentrations were measured in a survey in 1998 and cohort members were followed to evaluate the effects on health. Methods: Around 900 subjects (20-55 years old) randomly sampled in 4 municipalities of the area (Monte Amiata), have been followed from 1999 to 2015, by hospitalisation and mortality registries. Standardized Hospitalisation Ratios (SHRs) were performed, compared to a reference area. Competing-risks regression models were performed to test the association between As urinary concentration and risk of first hospitalisation. Results: SHRs show various increased risks, more frequently among males. Internal analyses show a positive association between As and skin diseases in the general population, the Hazard Ratio (HR) for 1 µg/l increase of As urinary concentration is 1.06 (90%CI 1.01-1.11) and in males, HR 1.08 (90%CI 1.02-1.14), between As and circulatory system diseases in males, HR 1.03 (90%CI 1.01-1.05). Conclusions: The results suggest an effect on skin diseases and circulatory system diseases and, considering the relative young age of cohort members, they could be considered also as predictive of future severer diseases.