No abstract

Patients with essential hypertension, in particular those with low plasma renin activity (PRA), are reported to have lowered plasma-ionized calcium and elevated parathyroid hormone levels. In this study 1 microgram alphacalcidol (1 alpha-hydroxy-vitamin D3) was given in a double-blind, placebo-controlled fashion over four months to 39 subjects with mild to moderate hypertension. There was a significant rise in PRA in the treatment group when compared to placebo (P less than .05), but the mean blood pressure response was similar in the two groups. When the treatment group was divided according to pretreatment PRA it was, however, seen that subjects with low PRA displayed a reduction in diastolic blood pressure, whereas those with high PRA raised their blood pressure compared to placebo. Also subjects with low pretreatment values for plasma-ionized calcium and high levels of parathyroid hormone showed a reduction in diastolic blood pressure. This study supports the idea of a relationship between calcium metabolism and the renin-aldosterone system in essential hypertension and describes a beneficial effect of vitamin D supplementation on blood pressure in low-renin hypertension.

The need for treatment of mild and apparently asymptomatic primary hyperparathyroidism (HPT) is questioned, but a raised incidence of cardiovascular disease has been regarded as evidence in favour of surgery. While it is well known that several risk factors for cardiovascular disease (hypertension, hyperlipidaemia and diabetes mellitus/impaired glucose tolerance) are overrepresented in HPT, it is not known whether surgery provides long-term normalization in these respects and reduces the risk of premature death. In a 15-year follow-up of a cohort of 172 subjects in whom mild hypercalcaemia was initially detected during a health screening, it was found that 56 subjects had died. 17 individuals had been operated on for HPT, 47 individuals were persistently hypercalcaemic, while 45 subjects had serum calcium within the normal range (seven individuals were lost to follow-up). There had been no significant differences in blood pressure between these groups of mildly hypercalcaemic patients and age- and sex-matched controls at the initial screening, but at follow-up blood pressure was significantly higher not only in subjects with persistent hypercalcaemia, but also in those who had been successfully operated on for HPT. Neither of the hypercalcaemic groups showed any significant deviations from the controls with regard to indices of lipid or glucose metabolism. These findings suggest that there is no simple cause-and-effect relationship to account for the propensity toward high blood pressure in primary HPT. Consequently it cannot be assumed that surgery for HPT will eliminate the increased risk of cardiovascular disease in patients with mild HPT.

A free health check, offered to 21417 20-63-year-old employees of the Stockholm City and County Council in 1971-73, was accepted by 15903 persons. The examination included a multichannel chemical analysis of a single blood sample. Serum calcium levels 211.0 mg/100 ml (2.75 mmol/l) and 211.1 mg/100 ml(2.78 mmol/l) were encountered in 3.9% and 1.1% of the population, respectively. Among subjects below 50 years of age, the calcium concentration was significantly higher in males than in females. This difference disappeared in older subjects, essentially because the calcium level decreased with advancing age in the men. To a further investigation were invited 178 subjects with a single serum calcium registration 311.1 mg/100 ml(2.78 mmol/l). Of this group, 95 persons (53.4%) exhibited hypercalcaemia (HC) on repeated testing. Twelve had been operated on prior to the actual follow-up and found to have parathyroid adenomata. Twenty subjects were on continuous treatment with diuretics of the thiazide type and seven had diseases that might induce HC (two had hyperthyroidism, two hypothyroidism, one sarcoidosis, one hypernephroma and one mammary carcinoma). In 56 patients the laboratory and physical examinations did not reveal any obvious cause for the HC except possible hyperparathyroidism (HPT). Eighty (84.2%) of the 95 HC subjects were women, mostly over 50 years. The 95 persons constituted 6.%0 of the total number of health-screened persons. The highest prevalence, 13%, was recorded for women aged 60-63. The prevalence of HPT in the total material was 3.6%0, which is higher than that found in several other studies. This is based on surgical findings to date.

S U M M A R Y1. The volatile phenols in sera of uraemic patients were analysed by gas-liquid chromatography. The concentrations ofp-cresol, 1.17 f0.58 (mean+ SD), and phenol, 0.44kO-39 mg/100 ml, were higher than the corresponding values (0.23 + 0.1 7 and 0.02 + 0.03 mg/ 100 m1,respectively) in control subjects. Both compounds were recovered mainly as acid labile conjugates, probably sulphate esters. No unconjugated phenol, 0-, m-, or p-cresol or conjugated derivatives of 0-or m-cresol were detected.2. When the standard hospital diet was replaced by an isocaloric low-protein diet, the concentration of p-cresol and urea in serum decreased in the two uraemic patients studied. The serum concentration of phenol was uninfluenced by this change of diet.3. One female patient was studied during treatment with peritoneal dialysis, which on two out of three occasions appeared to result in decreased concentrations of phenol and p-cresol in serum.