Hair Silicon as a Long-Term Mineral Exposure Marker in Coronary Artery Disease: A Pilot Study

Background: Coronary artery disease (CAD) is a multifactorial atherosclerotic disorder. Silicon (Si) is a trace mineral with potential antioxidant, anti-inflammatory, and lipid-modulating effects, but its clinical relevance in cardiovascular disease remains unclear. This study evaluated whether hair Si concentration-reflecting long-term exposure-is associated with CAD severity, clinical phenotype, risk factors, and systemic inflammation. Methods: A total of 130 patients with angiographically confirmed CAD (N = 36, 28% women) who met the inclusion criteria were enrolled. Disease severity was quantified using the Coronary Artery Surgery Study Score (CASSS) and SYNTAX score. Hair Si concentration was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Associations with demographic, clinical, biochemical, and inflammatory parameters were analyzed using non-parametric tests and multivariable ordinal logistic regression. Results: Median hair Si concentration was 21.3 ppm (range: 0.7-211.0). Hair Si levels showed no significant differences across CAD severity assessed by CASSS (H = 2.51; p = 0.47) or SYNTAX score (r = 0.079; p = 0.37). Similarly, no differences were observed between patients with stable angina and those presenting with acute coronary syndrome (p = 0.57) or between individuals with and without prior myocardial infarction. Hair Si concentration was unrelated to age, BMI, cardiovascular risk factors, lipid profile, or systemic inflammatory indices (all p > 0.2). Conclusions: Hair silicon concentration was not associated with CAD severity, phenotype, or systemic inflammation, suggesting that long-term Si exposure is metabolically neutral in advanced atherosclerosis. Unlike other minerals, silicon appears unlikely to serve as a diagnostic or prognostic biomarker in CAD, although its relevance may be confined to early vascular remodeling and primary prevention.