Serum zinc level is associated with aortic arch calcification in incident dialysis patients

BACKGROUND: Aortic calcification is a predictor of cardiovascular events. Several studies have shown an association between zinc deficiency and aortic calcification in patients with chronic kidney disease (CKD). We therefore investigated the associations between serum zinc levels and aortic arch calcifications in incident patients on dialysis. METHODS: We analyzed data from 773 patients who started dialysis at our hospital between January 2013 and December 2023. Aortic arch calcification was graded 0-3 on chest X-ray, as follows: grade 0, no visible calcification; grade 1, < 50% calcification in the arch; grade 2, 50% calcification; or grade 3, circumferential calcification. We defined grades 2-3 as severe calcification. We stratified patients into tertiles of serum zinc levels. RESULTS: Median serum zinc levels were 51, 47 and 44 μg/dL in patients with grade 0, 1 and 2-3 aortic arch calcification, respectively (p < 0.001). In multivariate analysis, low serum zinc level was independently associated with aortic arch calcification (OR 3.12, 95% CI 1.84-5.27; p < 0.001), particularly with severe aortic arch calcification (OR 6.91, 95% CI 3.11-15.40; p < 0.001). Adding serum zinc level to a model with established risk factors for aortic arch calcification ameliorated net reclassification (0.308; p < 0.001) and integrated discrimination improvement (0.018; p = 0.0074). More robust findings for net reclassification improvement (0.427; p < 0.001) and integrated discrimination improvement (0.035; p < 0.001) were observed with severe aortic arch calcifications. CONCLUSION: Low serum zinc level was independently associated with aortic arch calcification, and in particular, with severe aortic arch calcifications, among patients who started dialysis.