Influence of serum ferritin combined with blood cadmium concentrations on blood pressure and hypertension: From the Korean National Health and Nutrition Examination Survey

Background: Previous studies have suggested that cadmium (Cd) exposure and serum ferritin levels may influence the development of hypertension. Objective: We evaluated whether the association between blood Cd levels and the development of hypertension could be modified by serum ferritin levels in a representative sample of the adult population of South Korea. Methods: We used data from the Korean National Health and Nutrition Examination Survey (2008-2012), a nationally representative, cross-sectional, population-based study. We included 5752 adults aged 19 years and older who had records of blood Cd and ferritin levels and blood pressure measurements. Multiple logistic regression was used to examine the association between Cd exposure and the development of hypertension, as well as the modifying effects of serum ferritin. Results: Men had higher levels of serum ferritin, and women had higher levels of Cd. Smoking in men was significantly associated with high blood pressure and risk of hypertension. Significantly fewer women were smokers, and the combination of abnormal serum ferritin levels and high Cd levels was significantly associated with high systolic blood pressure [odds ratio (OR) = 2.11; 95% confidence interval (CI) = 1.04-4.28], high diastolic blood pressure (OR = 2.07; 95% CI = 1.04-4.12), and increased hypertension risk (OR = 1.83; 95% CI = 1.03-3.25) in women who never smoked. Conclusions: Our results provide further evidence that individuals with abnormal serum ferritin levels should limit their exposure to Cd to prevent hypertension.