Vol. 7, Issue 2, Part C (2025)

Background: Coronary artery disease (CAD) is the leading cause of global mortality, with coronary artery calcification (CAC) serving as a key marker of atherosclerotic burden. The relationship between calcium metabolism—dietary intake and serum levels—and CAC remains controversial, particularly regarding the differential effects of dietary versus supplemental calcium and the role of systemic calcium homeostasis in vascular calcification.
Objectives: This study aimed to assess the association between serum calcium levels and CAC score, evaluate the relationship between dietary calcium intake and CAC score, and identify independent predictors of CAC score in adults undergoing coronary CT angiography.
Methods: A cross-sectional study was conducted at Gazi Hariri Hospital, Baghdad, from March 1 to July 31, 2025, involving 120 participants aged 40-70 years. Dietary calcium intake was assessed using a culturally adapted Food Frequency Questionnaire. Fasting serum calcium was measured via colorimetric assay. CAC was quantified using non-contrast CT and Agatston scoring. Multivariable linear regression analysis identified independent predictors of CAC score, adjusting for age, sex, BMI, comorbidities, and lifestyle factors.
Results: Mean age was 54.86±8.92 years; 63.3% were male. CAC was absent in 49.2%, mild in 5.0%, moderate in 14.2%, and severe in 31.7%. Serum calcium was suboptimal (<9.8 mg/dL) in 73.3%. A moderate positive correlation was found between serum calcium and CAC score (Spearman’s r = 0.46, p<0.001). Multivariable analysis revealed serum calcium as a significant independent predictor of CAC (β = 0.210, p = 0.008), second to age (β = 0.351) and male sex (β = 0.305). No significant association was found between dietary calcium intake and CAC score. Traditional risk factors including diabetes, hypertension, smoking, and higher BMI were also independent predictors.
Conclusions: Serum calcium levels, not dietary calcium intake, are independently associated with coronary artery calcification. Systemic calcium homeostasis appears more critical than dietary intake in vascular calcification risk. These findings suggest that monitoring serum calcium may enhance cardiovascular risk stratification and caution against indiscriminate calcium supplementation, particularly in populations with metabolic dysregulation.