Impact of clusters of risk factors on subclinical coronary artery disease among asymptomatic rural population

Background: Although global risk assessment scores based on traditional cardiovascular risk factors are used to stratify the risk for coronary artery disease (CAD), a significant number of asymptomatic middle-aged adults experience coronary events without prior symptoms. Thus, it is important to early identify asymptomatic adults using subclinical markers of CAD such as  coronary artery calcium (CAC) to overcome such limitation.  However, there is near absence of research on CAC in Central Appalachia, a predominantly rural region, despite the potential to foster early detection and treatment of CAD and to motivate asymptomatic individuals towards beneficial behavioral and lifestyle changes. Therefore, we aimed to assess the impact of clusters of risk factors on CAC score, a measure of severity of CAD, to guide local and regional  clinical practice and formulate policies and programs to address the high prevalence of cardiovascular diseases  in the region.

Methods: The study included 1607 asymptomatic individuals from Central Appalachia who participated in screening for CAC scores between January 2011 and December 2012.   Self-reported data on demographics and 7 risk factors (obesity, diabetes, hypercholesterolemia, hypertension, smoking, sedentary lifestyle, and family history of CAD) were categorized into three clusters of risk factors (<3, 3-5, and >5) for the analysis. We examined the mean CAC scores by cluster and delineated the impact of clusters of risk factors on CAC score using multiple logistic regression.

 

Results: Of the participants in the CAC screening, the majority (98.3%) had at least one risk factor. Regardless of gender, the number of risk factors was significantly positively correlated with the mean CAC score (p<0.0001).  Overall, the mean CAC score was 93.1, 183.4, and 405.7 for those with <3, 3-5, and >5 risk factors, respectively (p<0.0001). After adjusting for gender and age, clusters of 3-5 and >5 risk factors were significantly associated with increased odds of having CAC by approximately two times [OR=1.92; 95% CI (1.52-2.42)] and six times [OR=6.12, 95% CI (3.05-12.29)], respectively.

Conclusion: Among this rural population, the number of clusters of risk factors was positively associated with higher CAC scores. This may indicate that the number of risk factors may help in determining the severity of CAD in this population before it progresses further to the extent when individuals develop symptoms or have cardiovascular events. This suggests the importance of primary prevention by aggressive risk factors modification for preventing future CAD and subsequent coronary events in these asymptomatic individuals.