Elsevier

The American Journal of Cardiology

Volume 102, Issue 9, 1 November 2008, Pages 1136-1141.e1
The American Journal of Cardiology

Coronary artery disease
Defining Normal Distributions of Coronary Artery Calcium in Women and Men (from the Framingham Heart Study)

https://doi.org/10.1016/j.amjcard.2008.06.038Get rights and content

Coronary artery calcium (CAC) may improve risk stratification for patients with coronary heart disease (CHD) beyond traditional risk factors. Subjects from the Framingham Heart Study Offspring and Third Generation cohorts (48% women; mean age 53 years) underwent noncontrast electrocardiographically triggered cardiac multidetector computed tomography. The prevalence of absolute CAC (Agatston score [AS] >0, >100, and >400) and relative age- and gender-specific strata (25th, 50th, 75th, 90th, and 95th percentiles) were determined in a healthy subset free of clinically apparent cardiovascular disease or CHD risk factors (n = 1,586), the overall sample at risk (n = 3,238), and subjects at intermediate Framingham risk score (FRS; 6% to 20% 10-year CHD event risk; n = 1,177). Absolute AS and relative cutoffs for CAC increased with age and FRS, were higher in men compared with women in each of the 3 cohorts, and increased from the healthy subset to the overall cohort to subjects at intermediate risk. However, in subjects with CAC, there was substantial disagreement between absolute and relative cut-off values for labeling subjects as having increased CAC. In general, more subjects were considered to have increased CAC using relative cut-off values, especially in women and younger subjects. Fewer subjects at intermediate FRS had increased CAC using comparable absolute versus relative cutoffs (men 32% at AS >100 vs 36% at >75th percentile; women 24% at AS >100 vs 34% at >75th percentile). In conclusion, we provided distributions of CAC in a healthy subset, the overall cohort, and subjects at intermediate risk from the Framingham Heart Study for both absolute and relative cut-off values for CAC. Absolute cutoffs underestimated the proportion of subjects with increased CAC, specifically in women, younger persons, and persons at intermediate CHD risk.

Section snippets

Methods

Subjects for this study were drawn from the Offspring and Third Generation cohorts of the community-based Framingham Heart Study. Selection criteria and study design have been described.1 Subjects in the analysis attended the Offspring seventh examination cycle (1998 to 2001) or Third Generation first examination cycle (2002 to 2005) and had complete risk-factor information (to allow determination of hypertension, lipids, smoking status, body mass index, and diabetes). Inclusion in the MDCT

Results

In the healthy reference sample, mean AS and the AS defining each percentile increased with age in both men and women and was consistently higher in men versus women within each age stratum (Table 1). Similar percentiles were noted in women who were about 10 years older than men. CAC prevalences were 30.3% (n = 500 of 1,652) in the overall healthy reference sample, 40.5% (n = 325 of 803) in men, and 20.6% (n = 175 of 849) in women. Although 20.6% of men aged <45 years had CAC, women <55 years

Discussion

In this study, we established normal values and distributions of CAC in a community-based sample of healthy white men and women free of clinically apparent cardiovascular disease and any CHD risk factors. We further established the absolute and relative distributions of CAC in a larger cohort of subjects free of clinically apparent cardiovascular disease and in subjects at intermediate risk of cardiovascular events.

We found similar age and gender associations of CAC in all 3 cohorts. There was

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This work was supported by the National Heart, Lung, and Blood Institute (NHLBI) Framingham Heart Study (National Institutes of Health/NHLBI Contract N01-HC-25195, Bethesda, maryland), Framingham, Massachusetts.

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