Cardiovascular diseases (CVDs), which include heart and vasculature diseases such as coronary heart disease (CHD), angina, heart attack (HA), heart failure (HF) and stroke, is a leading cause of death worldwide.(Xu et al. 2020a) According to a report from the American Heart Association (AHA) in 2010, CVD mortality accounted for nearly 33% of all mortality; and one person died from CVD every 38 seconds. Moreover, more than 785,000 people were estimated to have new or recurrent CVD every year.(Lloyd-Jones et al. 2010) Therefore, determining and controlling the risk factors for CVD are critical.(Phillips &Guazzi 2015, Thiara 2015) Some new risk factors were recently identified in addition to traditional factors, such as smoking, high cholesterol, physical inactivity, obesity and diabetes.(Aw et al. 2020, Koller &Agyemang 2020, Lloyd-Jones et al. 2010, Zhang et al. 2020). In particular, environmental pollution was found to contribute to the development of CVD and its risk factors.(Bi et al. 2020, Li et al. 2020c, So et al. 2020, Xu et al. 2020a) Of these, heavy metal pollutants (methylmercury, lead, chromium, etc.), which constitute one type of environmental pollutant, are associated with CVD and its risk factors.(Ali et al. 2020, Cao et al. 2020, Orisakwe et al. 2020) However, few studies have addressed the correlation between cadmium and CVD.
Cadmium (Cd) is a toxic heavy metal that is found in soil, water, seafood and vegetables.(Dennis et al. 2020, Gemeda et al. 2020, Koker et al. 2020, Orisakwe et al. 2015, Zhao et al. 2016) Many regions have reported levels of Cd exceeding the maximum permissible limit of 0.3 mg.kg− 1 established by the World Health Organization (WHO).(Li et al. 2020a, Orisakwe et al. 2015, Orisakwe et al. 2020, Pan et al. 2016, Wang et al. 2018) In addition to natural sources, various human activities can increase levels of Cd, including smoking, traffic emissions, metallurgical processes, nuclear energy production, mining, coal combustion and chemical manufacturing.(Li et al. 2019, Li et al. 2018, Sall et al. 2020, Wu et al. 2019) Furthermore, similar to other heavy metals, the stability and permeation of Cd lead to its persistence and accumulation in vivo.(Wang et al. 2015, Wu et al. 2019) Therefore, the relationships between Cd and many diseases have attracted considerable attention. Cd was found to increase not only the risk of carcinogenesis but also noncancer-related mortality;(Al Amin et al. 2020, Amadou et al. 2020, Suwazono et al. 2020) exposure to Cd was shown to be associated with kidney function decline, the development of neurodevelopmental disorders and inflammation of the airways.(Ijomone et al. 2020, Klein et al. 2020, Sotomayor et al. 2020) In addition, Cd was associated with elevated lipid levels and atherogenic indices, which might induce CVD in susceptible people.(Igharo et al. 2020, Xu et al. 2020b)
However, few studies have identified the relationship between Cd and CVD. A study in a Korean population showed that Cd was associated with the risk of stroke in people under the age of 60 years. An investigation in a larger and more representative population was needed to determine the correlation between the levels of Cd and CVD.(Jeong et al. 2020) Therefore, 38,223 subjects were included in this large population-based study based on data from the National Health and Nutrition Examination Survey (NHANES). Interestingly, the results showed that serum levels of Cd were positively related to CVD and its risk factors in adults.