Urinary calcium excretion in essential hypertension.
Patients with essential hypertension have been reported to have higher levels of urinary calcium excretion (UCaV) than normotensive persons. We tested the hypothesis that the calciuria of hypertension is due to dietary factors and evaluated several alternate mechanisms. UCaV was studied in 15 patients with essential hypertension compared with 16 age- and gender-matched normotensive control subjects. For subjects taking self-selected, free-living diets, the difference in UCaV between normotensive (130 +/- 14 mg/day) and hypertensive subjects (201 +/- 37 mg/day) was not significant (p = 0.1). However, in a controlled diet with moderately restricted sodium intake (88 mEq), urinary calcium excretion was significantly higher (p = 0.02) in the hypertensive than in the normotensive group receiving 400 mg calcium (204 +/- 25 vs 132 +/- 13 mg/day) and 1400 mg calcium (272 +/- 31 vs 187 +/- 25 mg/day). Twenty-four-hour UCaV was directly and significantly correlated with blood pressure (r = 0.63 for standing systolic blood pressure; p < 0.001). A 1000 mg oral calcium load caused similar changes in UCaV (0.12 +/- 0.11 vs 0.12 +/- 0.07 mg per 100 ml glomerular filtration) and serum ionized calcium level (0.06 +/- 0.08 vs 0.06 +/- 0.02 mmol/L) in normotensive and hypertensive subjects, respectively, suggesting that there was no difference in intestinal calcium absorption between the groups. Fasting UCaV did not differ between the hypertensive (8.9 +/- 4.5 mg per 2 hours) and normotensive groups (10.9 +/- 11.5 mg per 2 hours).(ABSTRACT TRUNCATED AT 250 WORDS)
Young
E W
EW
Division of Nephrology, Oregon Health Sciences University, Portland 97201.
Morris
C D
CD
McCarron
D A
DA
D000328:Adult; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000378:metabolism / Q000652:urine*; D004032:Diet; D005260:Female; D006801:Humans; D006973:Hypertension / Q000652:urine*; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000652:urine
D010281:Parathyroid Hormone; D010758:Phosphorus; D002117:Calcitriol; D002118:Calcium