Risk Factors for Calcified Atherosclerotic Plaque
Risk Factors for Calcified Atherosclerotic Plaque
The extent of shared risk factors for calcified atherosclerotic plaque (CAP) of the coronary, carotid, and abdominal aortic arteries is unknown. CAP was measured by computed tomography in 1,125 individuals in families affected with diabetes. Statistical methods adjusted for the lack of independence between observations. CAP scores were standardized, and tests of interaction were conducted to compare risk factor relations across vascular beds. The average age of the cohort was 61 years, and 84% had diabetes. The correlation in CAP scores across vascular beds ranged from 0.59 to 0.72. Age, albumin/creatinine ratio, hemoglobin A1c, diabetes, hypertension, and lipid-lowering therapy were correlated with quantity of CAP in all vascular beds (all p < 0.05); no differences in the strength of these relations were noted. In contrast, other significant correlates differed in the strength of their relations with CAP. The risk factor pack-years of smoking was most strongly correlated with CAP in the abdominal aorta (p < 0.005). Male gender, previous myocardial infarction, and coronary revascularization were most strongly correlated with CAP in the coronary arteries (p < 0.0001). In summary, CAPs of the coronary, carotid, and abdominal aortic arteries generally share common risk factors, even though several of these factors have a greater impact on CAP in one vascular bed than another.
Calcified atherosclerotic plaque (CAP) of the coronary arteries as measured by computed tomography is associated with prevalence and incidence of cardiovascular disease, even among subgroups at high risk such as persons with type 2 diabetes mellitus. Its correlates have been described, generally establishing the role of traditional cardiovascular disease risk factors in the etiology of CAP of the coronary arteries.
Very little is known regarding the distribution and determinants of CAP of the carotid arteries apart from a single study. In contrast, CAP of the abdominal aorta has been more extensively evaluated. Four epidemiologic studies have reported associations with cardiovascular disease risk factors. Furthermore, CAP of the abdominal aorta as quantified by lateral lumbar radiographs is an independent predictor of incident coronary heart disease and congestive heart failure.
Atherosclerosis is a systemic disorder, occurring throughout the arterial tree. Despite this, the quantity of calcification in atherosclerotic plaques is only moderately correlated across vascular beds, ranging from 0.28 to 0.59. This leaves a large portion of the variance of CAP unexplained. Differences in hemodynamic forces across the vasculature are thought to be responsible for differences in responses to systemic risk factors across the vascular beds. However, information is limited on the selective atherosclerotic response of different vascular beds to risk factors. Noninvasive methods such as computed tomography provide the opportunity for an assessment of global atherosclerotic risk.
The literature regarding the epidemiology of CAP is lacking in two specific areas. First, there are few reports of risk factor relations with CAP across multiple vascular beds in a single cohort. Second, few data are available that describe the correlates of CAP of the carotid arteries. The present study attempts to overcome these gaps. CAP was quantified in three vascular beds (coronary, carotid, and abdomen) by use of computed tomography, along with an extensive risk factor assessment in a sibling study of 1,125 individuals with and without type 2 diabetes mellitus. The statistical approach used provides a valid comparison of risk factor associations across the three vascular beds.
Abstract and Introduction
Abstract
The extent of shared risk factors for calcified atherosclerotic plaque (CAP) of the coronary, carotid, and abdominal aortic arteries is unknown. CAP was measured by computed tomography in 1,125 individuals in families affected with diabetes. Statistical methods adjusted for the lack of independence between observations. CAP scores were standardized, and tests of interaction were conducted to compare risk factor relations across vascular beds. The average age of the cohort was 61 years, and 84% had diabetes. The correlation in CAP scores across vascular beds ranged from 0.59 to 0.72. Age, albumin/creatinine ratio, hemoglobin A1c, diabetes, hypertension, and lipid-lowering therapy were correlated with quantity of CAP in all vascular beds (all p < 0.05); no differences in the strength of these relations were noted. In contrast, other significant correlates differed in the strength of their relations with CAP. The risk factor pack-years of smoking was most strongly correlated with CAP in the abdominal aorta (p < 0.005). Male gender, previous myocardial infarction, and coronary revascularization were most strongly correlated with CAP in the coronary arteries (p < 0.0001). In summary, CAPs of the coronary, carotid, and abdominal aortic arteries generally share common risk factors, even though several of these factors have a greater impact on CAP in one vascular bed than another.
Introduction
Calcified atherosclerotic plaque (CAP) of the coronary arteries as measured by computed tomography is associated with prevalence and incidence of cardiovascular disease, even among subgroups at high risk such as persons with type 2 diabetes mellitus. Its correlates have been described, generally establishing the role of traditional cardiovascular disease risk factors in the etiology of CAP of the coronary arteries.
Very little is known regarding the distribution and determinants of CAP of the carotid arteries apart from a single study. In contrast, CAP of the abdominal aorta has been more extensively evaluated. Four epidemiologic studies have reported associations with cardiovascular disease risk factors. Furthermore, CAP of the abdominal aorta as quantified by lateral lumbar radiographs is an independent predictor of incident coronary heart disease and congestive heart failure.
Atherosclerosis is a systemic disorder, occurring throughout the arterial tree. Despite this, the quantity of calcification in atherosclerotic plaques is only moderately correlated across vascular beds, ranging from 0.28 to 0.59. This leaves a large portion of the variance of CAP unexplained. Differences in hemodynamic forces across the vasculature are thought to be responsible for differences in responses to systemic risk factors across the vascular beds. However, information is limited on the selective atherosclerotic response of different vascular beds to risk factors. Noninvasive methods such as computed tomography provide the opportunity for an assessment of global atherosclerotic risk.
The literature regarding the epidemiology of CAP is lacking in two specific areas. First, there are few reports of risk factor relations with CAP across multiple vascular beds in a single cohort. Second, few data are available that describe the correlates of CAP of the carotid arteries. The present study attempts to overcome these gaps. CAP was quantified in three vascular beds (coronary, carotid, and abdomen) by use of computed tomography, along with an extensive risk factor assessment in a sibling study of 1,125 individuals with and without type 2 diabetes mellitus. The statistical approach used provides a valid comparison of risk factor associations across the three vascular beds.