Environmental Cadmium Exposure, Dietary Calcium Intake and Risk of Hypertension

摘要

Background: Cadmium is known to cause hypertension in animals, yet their association in epidemiologic studies has been inconsistent and mechanism of association is still unclear. Cadmium may interfere with biological functions of calcium which are critical to blood pressure regulation, but little is known about interactive effects of dietary calcium intake and cadmium on blood pressure or hypertension in general population. Aims:This study examined associations between blood cadmium exposure and hypertension and investigated whether intake of dietary calcium attenuates the effect of cadmium on hypertension in the elderly. Methods: We examined 417 participants between 60 to 87 years from a community-based panel of elderly. Blood cadmium levels were measured by graphite furnace-atomic absorption spectrometry, and daily dietary calcium intake was calculated from food frequency questionnaires. Logistic regression models were fit to evaluate the association of blood cadmium levels and calcium intake with a risk of hypertension, controlling for potential confounders. Results: Participants with higher cadmium exposure combined with lower calcium intake (vs. lower cadmium exposure and higher calcium intake based on cut-offs at median value) had significant odds ratios (ORs) for hypertension (2.6; 95% confidence interval (CI): 1.3 to 4.9) that was larger than ORs for those of higher cadmium exposure with higher calcium intake (1.7; 95% CI: 0.9 to 3.2) and lower cadmium exposure with lower calcium intake (1.9; 95% CI: 0.8 to 4.2). Conclusions: Our findings show that environmental cadmium exposure is an important risk factor for hypertension among elderly adults and suggest that diet containing an appropriate intake of calcium may attenuate the risk of hypertension attributable to cadmium.