Low-level cadmium exposure and cardiovascular outcomes in elderly Australian women: A cohort study

Background: Cadmium has been associated with increased risk of cardiovascular disease (CVD) in observational studies, however there has been a limited focus on this relationship in women. Objectives: This study investigated the association of urinary cadmium (UCd) concentrations with CVD outcomes and all-cause mortality in elderly Western Australian (WA) women. Methods: UCd excretion was measured at baseline in 1359 women, mean age 75.2 +/- 2.7 years and 14.5 years of atherosclerotic vascular disease (ASVD) hospitalisations and deaths, including both the principle cause of death and all associated causes of death. Health outcome data were retrieved from the Western Australian Data Linkage System. Cox regression analysis was used to estimate hazard ratios of ASVD and all-cause mortality. UCd was In-transformed and models were adjusted for demographic and CVD risk factors. Results: Median (IQR) concentration of UCd was 0.18 (0.09-0.32) mu g/L. In multivariable-adjusted analyses per In unit (equivalent to similar to 2.7 fold) increase in UCd, there was a 36% increase in the risk of death from heart failure and 17% increase in the risk of a heart failure event, respectively (HR = 1.36, 95% CI 1.11-1.67; HR = 1.17, 95% CI 1.01-1.35). When analyses were restricted to never smokers the relationship between UCd and death from heart failure remained (HR 1.29, 95% CI 1.01-1.63). Conclusions: This study suggests that even at low levels of exposure cadmium may be associated with heart failure hospitalisations and deaths in older women, however given the dilute nature of these urine samples, the results must be interpreted with caution.