Introduction:
Coronary artery calcium (CAC) is a marker of coronary atherosclerosis burden and is a strong predictor of cardiovascular events and overall mortality, especially in White populations. The distribution of CAC has been determined for a number of predominantly White populations; however, the distribution in ethnically admixed groups has not been well established. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a cohort with 15, 105 participants with an ethnic diversity (White, 52.2%; Brown, 28.2%; Black,16.1%; Asian, 2.5% and Native, 1.0%) is an unique opportunity to explore CAC scores differences among admixed populations.
Hypothesis:
to compare CAC scores obtained from an admixed population in Brazil with the results from the Multi Ethnic Study of Atherosclerosis (MESA).
Methods:
From the 15105 participants of ELSA-Brasil, a prospective study that enrolled civil servants aged 35 to 74 years, CAC scoring was performed on 3,400 individuals at the Sao Paulo site. Similar to previous studies, individuals with self-reported cardiovascular diseases or treated diabetes were excluded from the analysis. The final population included 2,753 individuals (men = 54%; median age = 48 years). Percentiles of CAC distribution were estimated using a two-part local regression fitting model, adapted to zero-inflated data and then compared to MESA CAC percentiles. Testing of the predictive role of age (years), sex, and ethnicity was done modeling a zero-inflated distribution for continuous data.
Results:
For the discrete part of CAC modelling, age, sex and ethnicity were predictors of CAC prevalence (CAC>0). For the ELSA-Brasil sample, increasing age (OR=1.14, p<0.001), male sex (OR: 3.61, p<0.001), and White ethnicity (OR=1.46 (against Blacks), p=0.02) were significantly associated with increased odds of having CAC>0. Different from expected, for the continuous part of CAC modelling, only age (p=0.02) was significantly associated with increased CAC values. Compared to MESA percentiles, the participants or ELSA-Brasil presented, overall, lower CAC values.
Conclusions:
Among this sample of apparently healthy Brazilian adults, we did observe significant differences in CAC prevalence by ethnicity, sex, and age. In contrast with MESA, the difference regarding the amount of CAC between men and women were smaller, suggesting an increased risk of Brazilian women compared to US women.