Indices of Mineral Metabolism in Relation to Blood Pressure in a Sample of a Healthy Population

Indices of mineral metabolism in blood and urine were analysed in relation to blood pressure in 97 healthy subjects aged 16–82 years. In a multivariate analysis, after allowing for the effects of sex, body mass index (BMI) and age, there was an inverse relationship between plasma level of ionized calcium and mean blood pressure (MBP) (β=-50.0 mmHg/mmol/l P-ionized calcium, p= 0.0005). In univariate analyses MBP also showed statistically significant inverse relationships with plasma ionized calcium, serum phosphate and renal threshold concentration of phosphate; positive relationships to MBP were found for fasting urinary excretion of calcium and cyclic adenosine monophosphate. However, when examined multivariately, only the relation between MBP and plasma ionized calcium persisted. This study supports previous findings of an inverse relationship between blood pressure and serum ionized calcium and extends the observations to the physiological range. It is further evident from this study that BMI and age should be taken into account in analyses of the relationship between blood pressure and mineral metabolism.     

Primary Hyperparathyroidism in Patients with Organic Brain Syndrome

ABSTRACT. In a retrospective study of 552 patients operated on for primary hyperparathyroidism (HPT) the effects of parathyroid surgery were selectively investigated in 13 elderly patients with organic brain syndrome. With a few exceptions, these 13 patients had mild or moderate hypercalcaemia but severe mental impairment. Ten patients had a clinical diagnosis of senile dementia and 12 had been admitted from a mental hospital. Postoperatively, eight patients improved mentally and seven of them were able to return to their homes or could be transferred to somatic units. The eight patients who showed improvement, either temporary or more permanent, had a relatively short duration of mental symptoms preoperatively, all less than 2 years, while those who did not improve mentally after surgery had a longer history of mental illness. Screening for HPT was subsequently performed in a psychogeriatric clinic to investigate the prevalence of HPT in this population. Hypercalcaemia and probable HPT was found in five (5%) of 101 patients. The results indicate that parathyroidectomy may improve the mental state in patients with HPT and organic brain syndrome. As a substantial number of patients in a psychogeriatric population seem to have HPT, the disease should be searched for in patients with newly diagnosed organic brain syndrome.     

Effects of physical exercise on serum calcium and parathyroid hormone

The effects of physical exercise on plasma ionized calcium, total serum calcium and parathyroid hormone (PTH) concentrations were evaluated in healthy subjects submitted to work on an ergometer bicycle. When the workload was increased stepwise there was a significant increase (P less than 0.001) in the calcium concentrations (ionized calcium from 1.13 +/- 0.03 (SD) to 1.24 +/- 0.03 mmol 1(-1) and total calcium from 2.35 +/- 0.07 to 2.48 +/- 0.07 mmol 1(-1] when the workload exceeded approximately 65% of the estimated maximum--i.e. a load that caused accumulation in blood of lactic acid. The rise in plasma ionized calcium was, therefore, presumably largely attributed to the acidosis but reduction of plasma volume and influx from extracellular sources might also have contributed. Beta blockade (with oral intake of propranolol) reduced physical capacity, shortened the duration of work and caused less acidosis. These factors were probably responsible for a smaller rise in ionized calcium during beta blockade (7 +/- 4%) than in control studies (21 +/- 5%) without medication in subjects examined during short-term maximal exercise. Long-term (1 h) steady-state work which caused fatigue without producing lactic acidosis did not affect the calcium concentrations. Despite the effects of work on calcium levels there was no discernible suppression of the PTH concentrations. This might have been due to a concomitant stimulation of PTH secretion by work.