Altered calcium homeostasis is correlated with the presence of metabolic syndrome and diabetes in middle-aged and elderly Korean subjects: the Chungju Metabolic Disease Cohort study (CMC study)

Objective: To clarify the association of serum calcium level with metabolic syndrome (MetS) and diabetes in middle-aged and elderly Korean subjects.

Design and patients: We conducted a population-based, cross-sectional survey of 1329 participants aged over 40 years (median age 65.8) in a rural area of Chungju, Korea, in 2007.

Measurements: Serum level of albumin, calcium, 25-hydroxy-vitamin D and intact parathyroid hormone were measured in a central laboratory.

Results: The prevalence of MetS increased progressively with elevated serum albumin-corrected calcium levels (P<0.001 for trend). After adjusting for various covariates, subjects in the highest quintile group (2.45-2.99 mmol/L) compared with the lowest quintile group (2.05-2.24 mmol/L) of serum calcium levels had an odds ratio (OR) for having MetS of 3.11 (95% confidence intervals, CI, 1.95-4.97; P for trend<0.001). Excluding the subjects with hypocalcemia and hypercalcemia (n=1064) did not alter this significant association. After multiple adjustment, subjects with serum calcium levels in the fourth to fifth quintiles had a 2.0- to 3.0-fold increased OR of having diabetes (first quintile reference, fourth quintiles OR 2.38; 95% CI 1.32-4.28, fifth quintiles OR 3.32; 95% CI 1.87-5.88; P for trend<0.001).The associations of serum calcium levels with the incidences of MetS or diabetes were unchanged after adjustment for 25(OH)D and PTH levels.

Conclusions: Altered calcium homeostasis was associated with an increased risk of having MetS and diabetes in this demographic group.