Coincident diabetes mellitus and primary hyperparathyroidism

Abstract

The prevalence of diabetes mellitus in primary hyperparathyroidism is approximately 8% and that of primary hyperparathyroidism in diabetic patients is approximately 1%. Both values are about three-fold higher than the respective expected prevalences in general populations. Patients with both disorders are over 40 years of age and 80% are female; 22% have type 1 and 78% type 2 diabetes. Primary hyperparathyroidism presents first in approximately 20% of patients, and diabetes mellitus in 40%; both disorders present together, or within 1 year, in 40%. Approximately 40% of patients with primary hyperparathyroidism have impaired glucose tolerance. Insulin resistance is present in hyperparathyroidism and probably arises from a raised intracellular free calcium concentration which, by decreasing normal insulin-stimulated glucose transport, increases the requirement for insulin: if this insulin resistance progresses, impaired glucose tolerance and diabetes mellitus would result. Parathyroidectomy has been followed by regression of diabetes and of impaired glucose tolerance in some but not all patients. Early diagnosis of the second disorder is clinically desirable when one disorder is present. Hyperparathyroid patients should therefore be screened for impaired glucose tolerance and diabetes annually, and pre-operatively. Diabetic patients should be checked for hypercalcaemia at appropriate intervals; although only 1% of them may have hyperparathyroidism, this disorder if untreated is associated with hypertension, to which diabetic patients are already prone.

Serum calcium is independently associated with insulin sensitivity measured with euglycaemic–hyperinsulinaemic clamp in a community-based cohort

“…This is supported by previous experimental data [8,9]. Increasing intracellular calcium levels have been shown to decrease the effect of insulin in adipocytes due to the reduced number of glucose transporters (GLUT4) and decreased insulin receptor activity [4,[28][29][30][31]. In an autopsy study performed in consecutive patients, it was shown that parathyroid adenomas and hyperplasia were far more common than the expected prevalence of overt hypercalcaemia [32].…”

“…Previous reports have also shown that patients with diabetes have elevated serum levels of calcium compared with nondiabetic individuals [3][4][5], and that the serum levels of calcium increase even further with decreasing metabolic control [3,4]. Moreover, in diseases with supranormal levels of serum calcium, such as primary hyperparathyroidism, there is a two-to fourfold higher prevalence of NIDDM and prediabetic states than in the general population [4,6,7]. Less is known about the relationship between serum calcium concentration and the two underlying causes of diabetes: insulin sensitivity and defective insulin secretion.…”

Serum calcium level is associated with metabolic syndrome in the general population: FIN-D2D study

“…In diseases with markedly elevated serum calcium, such as primary hyperparathyroidism, there is a two-to four-fold higher prevalence of type 2 diabetes and glucose intolerance compared with the general population (5). Increased parathyroid hormone (PTH) could stimulate calcium channels to increase calcium influx and the levels of intracellular calcium, which would influence insulin sensitivity and hypertension (6).…”

Association of serum phosphate levels with glucose tolerance, insulin sensitivity and insulin secretion in non-diabetic subjects

“…In patients with primary hyperparathyroidism (pHPT) the prevalence of type 2 diabetes (T2DM) is three times higher compared to healthy subjects (Taylor and Khaleeli, 2001). pHPT is also associated with impaired glucose tolerance (IGT) and reduced insulin sensitivity (IS) (Ljunghall et al, 1983).…”