Endocrine Abstracts

Objectives: Considerable evidence shows that increased serum calcium levels are associated with metabolic disorders, cardiovascular disease and increased mortality. This study investigated whether serum calcium, within a normal range, is significantly associated with serum fibrinogen and homocysteine, markers of increased cardiovascular disease risk in non-diabetic Korean subjects.

Methods: A cross-sectional analysis was performed on 1096 subjects (mean age, 55.1±11.1 years; 36.1% women) undergoing a general health checkup. Serum biochemistry was analyzed including serum albumin-corrected calcium (Ca_c), insulin resistance (IR, using homeostasis model assessment [HOMA]), fibrinogen, and homocysteine.

Results: Compared with patients within the lowest Ca_c quartile, those with higher Ca_c levels had increased fibrinogen and homocysteine levels as well as an increased proportion of smoking and dyslipidemia, and HOMA-IR. Correlation analyses revealed linear relationships for Ca_c with fibrinogen and homocysteine in both genders. After adjustment for confounding factors, serum Ca_c was significantly associated with high fibrinogen (odds ratio [OR] for the highest vs the lowest quartile=1.76, 95% confidence interval [CI]=1.10–2.83, P=0.020) and homocysteine (OR=1.82, 95% CI=1.22–3.71, P=0.008). Multivariate regression models showed that Ca_c was linearly associated with fibrinogen (standardized β=0.14, P<0.001) and homocysteine (standardized β=0.07, P=0.009).

Conclusions: High normal calcium concentrations were independently associated with increased levels of fibrinogen and homocysteine. Further investigation is needed to validate whether slightly increased calcium levels within the normal range indicate a higher risk of cardiovascular disease.