Association of serum calcium concentrations with fibrinogen and homocysteine in non-diabetic Korean subjects

Abstract

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 nondiabetic Korean subjects.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.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, 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] = 1.09-2.83, P = 0.02) and homocysteine (OR = 1.83, 95% CI = 1.07-3.11, P = 0.027). Multivariate regression models showed that Ca c was linearly associated with fibrinogen (standardized b = 0.14, P < 0.001) and homocysteine (standardized b = 0.07, P = 0.009).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.Abbreviations: BMI = body mass index, BP = blood pressure, Cac = serum albumin-corrected calcium, CI = confidence interval, CRP = C-reactive protein, CV = cardiovascular, CVD = cardiovascular disease, FPI = fasting plasma insulin, GFR = glomerular filtration rate, HDL-C = high-density lipoprotein cholesterol, HOMA = homeostasis model assessment, IR = insulin resistance, LDL-C = low-density lipoprotein cholesterol, MDRD = modification of diet in renal disease, OR = odds ratio, PTH = parathyroid hormone, ROS = reactive oxygen species, SNP = single nucleotide polymorphism, TC = total cholesterol, TG = triglycerides, TXA2 = thromboxane A2, WC = waist circumference.