Sex-Specific Impact of Serum Calcium Levels on Acute Coronary Syndrome Risk: A 19-Year Cohort Study in Korea

<b>Background:</b> This study aims to investigate the association between serum calcium levels and acute coronary syndrome (ACS) risk, examining whether this relationship differs by sex, given the known differences in calcium metabolism and hormonal influences between males and females. <b>Methods:</b> Utilizing the Korean Genome Epidemiology Study (KoGES) prospective cohort data, our primary exposure variables were serum calcium level and sex. The incidence of ACS served as the main outcome of interest. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression analysis. An interaction analysis was conducted to assess the interaction effect of calcium level and sex on ACS incidence. <b>Results:</b> After adjusting for confounding variables, high calcium intake did not significantly increase ACS incidence, with a hazard ratio (HR) of 1.07 (95% CI: 0.90-1.26). There was also no significant difference in ACS risk between females and males (HR: 0.81, 95% CI: 0.61-1.04). However, interaction effect analysis revealed that higher calcium levels were associated with an increased risk of ACS only in females (HR: 1.24, 95% CI: 1.07-1.58), whereas the association in males was not statistically significant (HR: 0.90, 95% CI: 0.71-1.15). <b>Conclusion:</b> Our study results indicate that elevated serum calcium levels alone did not independently increase the risk of ACS; however, high serum calcium levels were associated with an increased risk of ACS in females but not in males, underscoring the importance of sex-specific factors in assessing and managing ACS risk and highlighting the necessity for personalized medical approaches to improve cardiovascular health outcomes for women.