Association of blood cadmium with all-cause and cause-specific mortality in patients with hypertension

Abstract

BackgroundCadmium is a commonly found heavy metal with a prolonged biological half-life, which results in long-term health burden for the population. Prior studies have demonstrated an association between blood cadmium and hypertension. However, few studies examined the relationship between blood cadmium and long-term health outcomes in patients with hypertension. This study aimed to investigate the association of blood cadmium with mortality in patients with hypertension.MethodsThis study analyzed data from the National Health and Nutrition Examination Survey 1999–2012. Complex sampling-weighted multivariate Cox proportional hazards models were used to evaluate the hazard ratios (HRs) of all-cause, cardiovascular, and Alzheimer’s disease mortality in patients with hypertension classified by blood cadmium concentrations’ quantiles.ResultsThe study included 12,208 patients with hypertension with a median follow-up duration of 10.8 years. During this period, there were 4,485 all-cause deaths, including 1,520 cardiovascular deaths and 180 Alzheimer’s disease deaths. Compared with the lowest quintile of blood cadmium (≤0.25 μg/L) group, the highest quintile of blood cadmium (≥0.80 μg/L) group’s adjusted HRs were 1.85 (95% CI, 1.59–2.14) for all-cause mortality, 1.76 (95% CI, 1.33–2.34) for cardiovascular mortality, and 3.41 (95% CI, 1.54–7.51) for Alzheimer’s disease mortality. Additionally, the adjusted HR for cardiovascular mortality was 2.12 (95% CI, 1.36–3.30) in never-smoking patients with hypertension.ConclusionHigher blood cadmium is associated with increased risks of all-cause, cardiovascular, and Alzheimer’s disease mortality in patients with hypertension. The effect of blood cadmium on cardiovascular mortality may be more pronounced in never-smoking hypertensive patients.