Statistical analysis. For descriptive purposes, subjects were
classified into four coronary calcification groups: none (calcium
score 0), mild to moderate (calcium score 1 to
400), severe (calcium score 401 to 1,000) and very severe
(calcium score 1,000). This classification is a modification
of the categorization proposed by Rumberger et al. (14),
who recommended dividing coronary artery calcification
scores into four categories.