OBJECTIVE

To evaluate the association of coronary artery calcium (CAC) and coronary heart disease (CHD) events among young and elderly individuals.

PARTICIPANTS AND METHODS

This is a secondary analysis of data from a prospective, multiethnic, population-based cohort study designed to study subclinical atherosclerosis. A total of 6809 persons 45 through 84 years old without known cardiovascular disease at baseline were enrolled from July 2000 through September 2002. All participants had CAC scoring performed and were followed up for a median of 8.5 years. The main outcome measures studied were CHD events, defined as myocardial infarction, definite angina or probable angina followed by revascularization, resuscitated cardiac arrest, or death attributable to CHD.

RESULTS

Comparing individuals with a CAC score of 0 with those with a CAC score greater than 100, there was an increased incidence of CHD events from 1 to 21 per 1000 person-years and 2 to 23 per 1000 person-years in the 45- through 54-year-old and 75- through 84-year-old groups, respectively. Compared with a CAC score of 0, CAC scores of 1 through 100 and greater than 100 impart an increased multivariable-adjusted CHD event risk in the 45- through 54-year-old and 75- through 84-year-old groups (hazard ratio [HR], 2.3; 95% CI, 0.9-5.8; for those 45-54 years old with CAC scores of 1-100; HR, 12.4; 95% CI, 5.1-30.0; for those 45-54 years old with CAC scores >100: HR, 5.4; 95% CI, 1.2-23.8; for those 75-84 years old with CAC scores of 1-100; and HR, 12.1; 95% CI, 2.9-50.2; for those 75-84 years old with CAC scores >100).

CONCLUSION

Increased CAC imparts an increased CHD risk in younger and elderly individuals. CAC is highly predictive of CHD event risk across all age groups, suggesting that once CAC is known chronologic age has less importance. The utility of CAC scoring as a risk-stratification tool extends to both younger and elderly patients.