Coronary Artery Calcium (CAC) is a sign of advanced atherosclerosis and an independent risk factor for cardiac events. Here, we describe CAC-distributions in an unselected aged population and compare modelling methods to characterize CAC-distribution. CAC is difficult to model because it has a skewed and zero inflated distribution with over-dispersion. Data are from the AGES-Reykjavik sample, a large population based study [2002-2006] in Iceland of 5,764 persons aged 66-96 years. Linear regressions using logarithmic- and Box-Cox transformations on CAC+1, quantile regression and a Zero-Inflated Negative Binomial model (ZINB) were applied. Methods were compared visually and with the PRESS-statistic, R(2) and number of detected associations with concurrently measured variables. There were pronounced differences in CAC according to sex, age, history of coronary events and presence of plaque in the carotid artery. Associations with conventional coronary artery disease (CAD) risk factors varied between the sexes. The ZINB model provided the best results with respect to the PRESS-statistic, R(2), and predicted proportion of zero scores. The ZINB model detected similar numbers of associations as the linear regression on ln(CAC+1) and usually with the same risk factors.

中文翻译：

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AGES-Reykjavik 研究中老年人的冠状动脉钙分布。

冠状动脉钙化 (CAC) 是晚期动脉粥样硬化的标志，也是心脏事件的独立危险因素。在这里，我们描述了未选择的老年人群中的 CAC 分布，并比较了表征 CAC 分布的建模方法。CAC 很难建模，因为它具有过度分散的偏斜和零膨胀分布。数据来自 AGES-Reykjavik 样本，这是一项在冰岛进行的大型人口研究 [2002-2006]，涉及 5,764 名 66-96 岁的人。应用了在 CAC+1 上使用对数和 Box-Cox 变换的线性回归、分位数回归和零膨胀负二项式模型 (ZINB)。方法进行了视觉比较，并与新闻统计、 R(2) 和检测到的关联与同时测量的变量的数量。CAC 在不同性别、年龄、冠状动脉事件史和颈动脉斑块的存在。与传统冠状动脉疾病 (CAD) 危险因素的关联因性别而异。ZINB 模型在 PRESS 统计量、R(2) 和预测的零分比例方面提供了最佳结果。ZINB 模型检测到与 ln(CAC+1) 的线性回归相似数量的关联，并且通常具有相同的风险因素。