Dietary calcium intake and serum calcium levels in relation to coronary artery calcium score assessed by CT angiography: A clinical correlation study

Abstract

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 (