1.
Serum calcium and incident diabetes: an observational study and meta-analysis.
Sing, CW, Cheng, VK, Ho, DK, Kung, AW, Cheung, BM, Wong, IC, Tan, KC, Salas-Salvadó, J, Becerra-Tomas, N, Cheung, CL
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2016;(5):1747-54
Abstract
UNLABELLED The study aimed to prospectively evaluate if serum calcium is related to diabetes incidence in Hong Kong Chinese. The results showed that serum calcium has a significant association with increased risk of diabetes. The result of meta-analysis reinforced our findings. INTRODUCTION This study aimed to evaluate the association of serum calcium, including serum total calcium and albumin-corrected calcium, with incident diabetes in Hong Kong Chinese. METHODS We conducted a retrospective cohort study in 6096 participants aged 20 or above and free of diabetes at baseline. Serum calcium was measured at baseline. Incident diabetes was determined from several electronic databases. We also searched relevant databases for studies on serum calcium and incident diabetes and conducted a meta-analysis using fixed-effect modeling. RESULTS During 59,130.9 person-years of follow-up, 631 participants developed diabetes. Serum total calcium and albumin-corrected calcium were associated with incident diabetes in the unadjusted model. After adjusting for demographic and clinical variables, the association remained significant only for serum total calcium (hazard ratio (HR), 1.32 (95 % confidence interval (CI), 1.02-1.70), highest vs. lowest quartile). In a meta-analysis of four studies including the current study, both serum total calcium (pooled risk ratio (RR), 1.38 (95 % CI, 1.15-1.65); I (2) = 5 %, comparing extreme quantiles) and albumin-corrected calcium (pooled RR, 1.29 (95 % CI, 1.03-1.61); I (2) = 0 %, comparing extreme quantiles) were associated with incident diabetes. Penalized regression splines showed that the association of incident diabetes with serum total calcium and albumin-correlated calcium was non-linear and linear, respectively. CONCLUSIONS Elevated serum calcium concentration is associated with incident diabetes. The mechanism underlying this association warrants further investigation.
2.
Increased serum calcium levels and risk of type 2 diabetes in individuals at high cardiovascular risk.
Becerra-Tomás, N, Estruch, R, Bulló, M, Casas, R, Díaz-López, A, Basora, J, Fitó, M, Serra-Majem, L, Salas-Salvadó, J
Diabetes care. 2014;(11):3084-91
Abstract
OBJECTIVE Insulin resistance and secretion depend on calcium homeostasis. Cross-sectional studies have associated elevated serum calcium levels with markers of impaired glucose metabolism. However, only one prospective cohort study has demonstrated an increased risk of diabetes in individuals with increased serum calcium concentrations. The aim of the current study was to prospectively investigate the association between albumin-adjusted serum calcium concentrations and type 2 diabetes in subjects at high cardiovascular risk. RESEARCH DESIGN AND METHODS Prospective assessment of participants from two Spanish PREDIMED study centers where serum calcium levels were measured at baseline and yearly during follow-up. Multivariate-adjusted Cox regression models were fitted to assess associations between baseline and changes during follow-up in serum calcium levels and relative risk of diabetes incidence. RESULTS After a median follow-up of 4.78 years, 77 new cases of type 2 diabetes occurred. An increase in serum calcium levels during follow-up was related to an increased risk of diabetes. In comparison with individuals in the lowest tertile (-0.78 ± 0.29 mg/dL), the hazard ratio (HR) and 95% CI for diabetes incidence in individuals in the higher tertile of change (0.52 ± 0.13 mg/dL) during follow-up was 3.48 (95% CI 1.48-8.17; P for trend = 0.01). When albumin-adjusted serum calcium was analyzed as a continuous variable, per 1 mg/dL increase, the HR of diabetes incidence was 2.87 (95% CI 1.18-6.96; P value = 0.02). These associations remained significant after individuals taking calcium supplements or having calcium levels out of normal range had been excluded. CONCLUSIONS An increase in serum calcium concentrations is associated with an increased risk of type 2 diabetes in individuals at high cardiovascular risk.