RELATIONSHIP BETWEEN SERUM PARATHYROID-HORMONE LEVELS IN THE ELDERLY AND 24 H AMBULATORY BLOOD PRESSURES

Background An association between serum parathyroid hormone (PTH) leve ls in normotensive elderly subjects and blood pressure values had been reported, Objective To examine the relationship between PTH levels an d other biochemical markers of calcium metabolism in elderly subjects and 24 h ambulatory blood pressures. Methods We performed 24 h ambulat ory blood pressure recordings for 123 independent elderly subjects age d 63-88 years using a SpaceLabs 90207 recorder. Mean night-time blood pressures were calculated from the average of readings during sleep; m ean daytime blood pressures were calculated from the remaining recordi ngs, Demographic data and details concerning the alcohol consumption a nd medication usage of the subjects were recorded, Serum PTH, 25-hydro xy-vitamin D, albumin, renin, aldosterone, noradrenaline, creatinine a nd calcium levels were measured. Results Fifty-five patients were bein g administered antihypertensive therapy, Serum PTH levels correlated t o the nocturnal systolic blood pressure (SEP; beta = 0.29, P = 0.002), nocturnal diastolic blood pressure (DBP), daytime SEP and mean 24 h S EP on univariate and multivariate analysis. Aldosterone levels were re lated to nocturnal SEP in univariate analysis (beta = 0.21, P = 0.02) but the relationship was weakened when PTH levels were included in the analysis (beta = 0.16, P = 0.09). Nocturnal, daytime and mean 24 h bl ood pressures were not significantly related to serum calcium, 25-hydr oxy-vitamin D, age, body mass index and alcohol consumption. Sex was a significant predictor of the DBP, men having higher levels than did w omen (daytime DBP beta = 0.29, P = 0.001). Conclusions Serum PTH level s are related strongly to the blood pressure, particularly the nocturn al blood pressure in the elderly, It is not known whether PTH levels a re a consequence or a cause of the elevation in blood pressure.