Total serum calcium levels were measured in 12 865 men and 14 293 women, be
tween the ages of 25 and 97 years, in the Tromso Study during 1994 and 1995
. With the use of a sex-specific multiple linear regression model with age,
calcium, body mass index, cholesterol, HDL cholesterol, triglycerides, sys
tolic and diastolic blood pressure, and pulse as possible covariates, serum
calcium was significantly (P<0.001) and positively associated with systoli
c and diastolic blood pressure, serum cholesterol, and HDL cholesterol in b
oth sexes. A similar but weaker association was observed between serum calc
ium and triglycerides in men (P<0.01). In all age groups, serum calcium lev
els were higher in men with a history of myocardial infarction than in thos
e without, and the difference was significant (P<0.0001) in a linear regres
sion analysis adjusted for age. When all the other variables were also incl
uded in a logistic regression model, serum calcium was a highly significant
(P<0.0001) predictor of myocardial infarction in men, with an odds ratio o
f 1.2 per 0.1 mmol/L increase in serum calcium. In women, a nonsignificant
trend was again seen. Because the free or ionized form of calcium is the ph
ysiologically important form and serum calcium was not corrected for serum
albumin in our study, the results must be interpreted with caution. However
, it appears likely that serum calcium is a predictor of cardiovascular dis
ease in men.