Serum calcium and blood pressure.

The association between serum calcium and blood pressure was examined in a sample of 7,735 healthy middle-aged British men (The British Regional Heart Study). There was a small but significant correlation between serum calcium and both systolic and diastolic blood pressure (r = 0.15 and 0.11, respectively; P less than 0.0001) after adjusting for age. This association was diminished after adjustment for serum albumin, but remained significant (r = 0.10 and 0.07; P less than 0.0001). This finding is consistent with results from previous studies. To assess whether the association between serum calcium and blood pressure is independent of the levels of other blood constituents, 20 biochemical and haematological factors were examined to identify possible confounding factors. The association between calcium and blood pressure disappeared after adjustment for serum globulins and haematocrit in addition to age and serum albumin. Thus, these factors appear to mediate the weak association between serum calcium and both systolic and diastolic blood pressure. There does not appear to be an independent relationship between serum calcium and blood pressure.