Serum calcium is independently associated with insulin sensitivity measured with euglycaemic-hyperinsulinaemic clamp in a community-based cohort.
ABSTRACT Diabetes mellitus type 2 is associated with altered calcium metabolism. Moreover, in diseases with supranormal serum calcium levels, such as primary hyperparathyroidism, the prevalence of diabetes is increased. Relatively little is known about the relationship between serum calcium concentration and the underlying causes of diabetes-insulin resistance and defective insulin secretion-in the normocalcaemic general population.
We investigated associations between serum calcium concentration and insulin sensitivity and secretion in a population-based cohort of elderly men (Uppsala Longitudinal Study of Adult Men, n = 961). Insulin sensitivity index (M/I; glucose disposal rate [M] divided by mean insulin concentration [I]) was assessed using euglycaemic-hyperinsulinaemic clamp, and insulin secretion was estimated from the early insulin response (EIR) during an OGTT.
In a multivariable linear regression model adjusting for BMI, physical activity, smoking, consumption of tea, alcohol, coffee and dietary calcium, serum phosphate and serum creatinine, 1 SD increase in serum calcium was associated with 0.17 mg kg(-1) min(-1) (mU/l)(-1) x 100 (0.024 mg kg(-1) min(-1) [pmol/l](-1) x 100) decrease in M/I (p = 0.01). The results remained robust in individuals with normal fasting glucose, normal glucose tolerance and serum calcium within the normal range (n = 413, regression coefficient for 1 SD increase -0.45, p = 0.001). Serum calcium was not associated with EIR. Dietary intake of calcium was not independently associated with insulin sensitivity or EIR.
Our data support the notion that endogenous calcium may be involved early in the development of diabetes and that this effect is mediated mainly through effects on insulin sensitivity rather than defective insulin secretion. Dietary intake of calcium does not seem to influence insulin sensitivity.
Article: Serum calcium levels are associated with novel cardiometabolic risk factors in the population-based CoLaus study.[show abstract] [hide abstract]
ABSTRACT: Associations of serum calcium levels with the metabolic syndrome and other novel cardio-metabolic risk factors not classically included in the metabolic syndrome, such as those involved in oxidative stress, are largely unexplored. We analyzed the association of albumin-corrected serum calcium levels with conventional and non-conventional cardio-metabolic risk factors in a general adult population. The CoLaus study is a population-based study including Caucasians from Lausanne, Switzerland. The metabolic syndrome was defined using the Adult Treatment Panel III criteria. Non-conventional cardio-metabolic risk factors considered included: fat mass, leptin, LDL particle size, apolipoprotein B, fasting insulin, adiponectin, ultrasensitive CRP, serum uric acid, homocysteine, and gamma-glutamyltransferase. We used adjusted standardized multivariable regression to compare the association of each cardio-metabolic risk factor with albumin-corrected serum calcium. We assessed associations of albumin-corrected serum calcium with the cumulative number of non-conventional cardio-metabolic risk factors. We analyzed 4,231 subjects aged 35 to 75 years. Corrected serum calcium increased with both the number of the metabolic syndrome components and the number of non-conventional cardio-metabolic risk factors, independently of the metabolic syndrome and BMI. Among conventional and non-conventional cardio-metabolic risk factors, the strongest positive associations were found for factors related to oxidative stress (uric acid, homocysteine and gamma-glutamyltransferase). Adiponectin had the strongest negative association with corrected serum calcium. Serum calcium was associated with the metabolic syndrome and with non-conventional cardio-metabolic risk factors independently of the metabolic syndrome. Associations with uric acid, homocysteine and gamma-glutamyltransferase were the strongest. These novel findings suggest that serum calcium levels may be associated with cardiovascular risk via oxidative stress.PLoS ONE 01/2011; 6(4):e18865. · 4.09 Impact Factor