Do people with high blood pressure lose more calcium in their urine and have higher parathyroid hormone levels?

Details

Disorders of calcium metabolism have not generally been considered important clinically or in the disease processes of essential hypertension. However, the abstract notes recent reports suggesting that increased parathyroid gland function may be one of the more common endocrine disturbances associated with hypertension.

In this comparative observational pilot study, researchers measured serum parathyroid hormone (PTH) concentrations and routine blood and urine chemistries in 34 people with hypertension. Their mean PTH was 79.1 ± 3.1 muliter Eq/muliter, significantly higher than 66.9 ± 3.3 in an age- and sex-matched normotensive control population (p < 0.025; PTH units as reported in the abstract). Mean serum calcium was identical in the two populations, at 9.5 ± 0.1 mg%.

Compared with a second age- and sex-matched normotensive population, the participants with hypertension had significantly greater relative urinary calcium excretion, described as relative hypercalciuria (p < 0.005). At any given level of urinary sodium, they excreted more calcium.

The researchers interpreted these preliminary data as suggesting that parathyroid gland function may be enhanced in essential hypertension. They proposed that this increased gland activity appears, in part, to be an appropriate physiological response to previously unrecognized relative hypercalciuria, or a renal calcium leak, associated with essential hypertension.

They further proposed that the increased prevalence of hypertension among people with hyperparathyroidism probably represents the final event in a continuum that begins with obligatory urinary calcium losses in people with hypertension and has hyperparathyroidism as its pathological presentation. The authors concluded that follow-up experiments are needed to establish the importance of these preliminary pilot findings in the development of human and experimental hypertension.