Environmental Metals and Cardiovascular Disease in Adults: A Systematic Review Beyond Lead and Cadmium

Abstract

Published systematic reviews concluded that there is moderate to strong evidence to infer a potential role of lead and cadmium, widespread environmental metals, as cardiovascular risk factors. For other non-essential metals, the evidence has not been appraised systematically. Our objective was to systematically review epidemiologic studies on the association between cardiovascular disease in adults and the environmental metals antimony, barium, chromium, nickel, tungsten, uranium, and vanadium. We identified a total of 4 articles on antimony, 1 on barium, 5 on chromium, 1 on nickel, 4 on tungsten, 1 on uranium, and 0 on vanadium. We concluded that the current evidence is not sufficient to inform on the cardiovascular role of these metals because of the small number of studies. Few experimental studies have also evaluated the role of these metals in cardiovascular outcomes. Additional epidemiologic and experimental studies, including prospective cohort studies, are needed to understand the role of metals, including exposure to metal mixtures, in cardiovascular disease development.

Keywords: Atherosclerosis; Cardiovascular; Epidemiologic studies; Metals; Systematic review.

Figure 1. Flow diagram of the study selection process

Summary of inclusion and exclusion criteria used in this systematic review of studies investigating the association between environmental metals and atherosclerotic cardiovascular disease, 1 April 2016. * 10 references include the following studies with multiple environmental metals evaluated in unique study populations: Agarwal et al. (2011)[57] examined in NHANES 1999–2006 population urine antimony and tungsten. Navas-Acien et al. (2005)[58] examined in NHANES 1999–2000 urine antimony, barium and tungsten. Mendy et al. (2012)[20] examined in the NHANES 2007–2008 populations urine antimony, tungsten and uranium. Lind et al. (2012)[59] examined in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) population whole blood chromium and nickel.

Figure 2. Relative risks (RRs) for cardiovascular disease endpoints for a given change in chromium level

Squares and diamonds represent effect estimates and are proportional to the inverse of the variance of the log odds ratios, and lines represent 95% CIs. ^a Niskanen et al. only reported mean levels of urinary Cr among cases and controls; we derived RR and 95% CI via the linear discrimination method [157]. Abbreviations: NR, not reported; CHD, coronary heart disease; MI, myocardial infarction. Total N was reported where number of cases/non cases was not available. Pooled estimates within and across studies were pooled via inverse-variance weighted random effects.