Do nutrients modify the risk of cadmium on acute myocardial infarction among never smokers in the Danish Diet, Cancer and Health cohort?

BACKGROUND/AIM: Urine cadmium (U-Cd) is an established biomarker of long-term Cd exposure. U-Cd may be associated with risk of acute myocardial infarction (AMI), but results are equivocal at low biomarker levels. Nutrients including calcium (Ca), magnesium (Mg), and potassium (K) may play an important role in slowing atherosclerosis progression, though research findings with AMI have been inconsistent, and studies are limited in examining whether Cd-AMI associations are modified by these nutrients. METHODS: We analyzed data from a never smoking subgroup of the Danish Diet, Cancer, and Health (DCH) cohort, a prospective study of 50–64-year-old participants recruited between 1993-1997. Using a case-cohort design, with complete case analysis, we identified 1135 members of the randomly selected subcohort and 776 AMI cases through 2015. We quantified Cd (μg/g) and Ca (mg/g) concentrations in baseline urine samples. We calculated combined nutrient dietary intake scores (3-12 points) from Ca, K, and Mg food frequency questionnaires. We estimated adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) using Cox proportional hazard models, adjusted for sex, education, passive smoking, alcohol, waist circumference, exercise and healthy diet. We stratified by median cutpoints and defined as high and low urine Ca (U-Ca) concentrations (median: 117.5 μg/g) or dietary intake scores (median: 8 points). RESULTS: Results were not materially different when stratified. Among high and low U-Ca groups, HRs for AMI were 1.27 (95% CI: 0.81, 1.98) and 0.93 (95% CI: 0.62, 1.41), respectively, when comparing highest vs. lowest U-Cd quartiles. HRs among high and low dietary intake scores were 0.96 (95% CI: 0.62, 1.49) and 1.25 (95% CI: 0.80, 1.95), respectively, when comparing highest vs. lowest U-Cd quartiles. CONCLUSIONS: We did not find evidence that nutrient levels modified the association between low-level Cd and AMI among never smokers. KEYWORDS: metals, nutrients, cadmium, myocardial infarction, cardiovascular health