Blood pressure and chemistry: some correlations and apparent correlations

Association of serum albumin concentration, serum ionized calcium concentration, and blood pressure in the Third National Health and Nutrition Examination Survey

A few small studies of white persons have found a positive association between serum albumin and blood pressure. However, this association might be due to ionized calcium. No data on albumin or ionized calcium have appeared for African Americans or Hispanics, and few for women. To explore the association of serum albumin (g/L) and ionized calcium (mmol/L) with both systolic and diastolic blood pressure, data from the Third National Health and Nutrition Examination Survey, 1988-94, were analyzed. Results from multiple regressions, controlling for age, overweight, alcohol intake, hematocrit, pulse, antihypertensive medication, and smoking indicate that serum albumin is positively correlated (P < 0.01) to systolic and diastolic blood pressure among non-Hispanic white men 25-59 and 60-89 years old. Ionized calcium was associated negatively with diastolic blood pressure among younger Mexican-American men. In this national sample, serum albumin was consistently associated with systolic and diastolic blood pressure only among non-Hispanic white men.

Lack of evidence of low ionized calcium levels in systemic hypertension

An epidemiologic screening survey was conducted in 325 male industrial workers to investigate the relation between serum total and ionized calcium concentrations and blood pressure. No relation was found. Previous reports of lower serum ionized calcium levels in hypertensive patients may be related to methodologic deficiencies both in the selection of subjects and in ionized calcium measurement. These data do not support the concept that increased blood pressure levels are related to calcium deficiency or to abnormal plasma calcium homeostasis.