Zinc compound air releases from Toxics Release Inventory facilities and cardiovascular disease mortality rates

Background: Inhaled zinc has been found in association with cardiopulmonary toxicity. However, limited human epidemiologic studies are available. This study analyzed the association between covariate-adjusted cardiovascular (CVD) mortality rates and zinc compound air releases in the United States. Methods: We conducted an ecological analysis on the association between zinc compound air releases for 1991-2000 using the Toxics Release Inventory database and average age-adjusted CVD mortality for 2006-2010, adjusting for race/ethnicity composition and several health and socioeconomic factors. Models were estimated for males and females and for metropolitan and nonmetropolitan counties. Results: Zinc compound air releases were positively associated with increased adjusted CVD mortality rates in all four models (beta=0.0085, p < 0.0001 for males in nonmetropolitan counties; beta=0.0093, p < 0.0001 for males in metropolitan counties; beta=0.0145, p < 0.0001 for females in nonmetropolitan counties; and beta=0.0098, p < 0.0001 for females in metropolitan counties). Results were largely robust to various sensitivity analyses. Conclusion: This study provides epidemiological evidence for possible CVD health impacts of inhaled zinc in the United States. Although the strongest effect was found for females in nonmetropolitan counties, the associations were consistent in nonmetropolitan or metropolitan counties for both genders. (C) 2015 Elsevier Inc. All rights reserved.