SERUM-CALCIUM - A NEW, INDEPENDENT, PROSPECTIVE RISK FACTOR FOR MYOCARDIAL-INFARCTION IN MIDDLE-AGED MEN FOLLOWED FOR 18 YEARS

Background: Primary hyperparathyroidism (HPT) is a disease characteriz ed by hypercalcemia, and associated with an increased mortality in car diovascular diseases. However, serum calcium levels within the normal range have not been evaluated as a prospective cardiovascular risk fac tor. Methods: A cohort of males aged 50 (n = 2183) were investigated i n 1970-1973 for serum calcium and known cardiovascular risk factors. T hey were then followed up over the next 18 years. Results: During the follow-up period, 180 subjects experienced a myocardial infarction (MI ). The serum calcium levels were significantly elevated at the baselin e (2.37 +/- 0.09 SD versus 2.35 +/- 0.09 mmol/l, p < 0.03) in the subj ects who developed a MI when compared with the rest of the cohere. Als o blood pressure, body mass index (BMI), fasting insulin, serum choles terol, serum triglycerides, and the atherogenic index were significant ly elevated in the MI group (p < 0.01), while HDL-cholesterol was lowe r at the baseline investigation (p < 0.01). Cox's proportional hazard analysis showed that only serum calcium (p < 0.01), BMI (p < 0.0003), diastolic blood pressure (p < 0.0009), and the atherogenic index (p < 0.002) were significantly independent risk factors for MI. The range o f serum calcium levels from the mean value, -2 SDs to the mean Value 2 SDs corresponds to a variation in estimated risk for MI ranging fro m 0.06 to 0.15. Conclusions: Serum calcium was found to be an independ ent, prospective risk factor for MI in middle-aged males suggesting a role for extracellular calcium levels in the atherosclerotic process. (C) 1997 Elsevier Science Inc.