The relation between coronary artery calcification in asymptomatic subjects and both traditional risk factors and living in the city centre: a DanRisk substudy

Abstract

To evaluate the association between the risk factor for living in the city centre as a surrogate for air pollution and the presence of coronary artery calcification (CAC) in a population of asymptomatic Danish subjects. A random sample of 1825 men and women of either 50 or 60 years of age were invited to take part in a screening project designed to assess risk factors for cardiovascular disease (CVD). Noncontrast cardiac computed tomography was performed on all subjects, and their Agatston scores were calculated to evaluate the presence of subclinical coronary atherosclerosis. The relationship between CAC and several demographic and clinical parameters was evaluated using multivariate logistic regression. A total of 1225 individuals participated in the study, of whom 250 (20%) were living in the centres of major Danish cities. Gender and age showed the greatest association with the presence of CAC: the odds ratio (OR) for men compared with women was 3.2 [95% confidence interval (CI) 2.5-4.2; P < 0.0001], and the OR for subjects aged 60 versus those aged 50 years was 2.2 (95% CI 1.7-2.8; P < 0.0001). Other variables independently associated with the presence of CAC were diabetes and smoking with ORs of 2.0 (95% CI 1.1-3.5; P = 0.03) and 1.9 (95% CI 1.4-2.5, P < 0.0001), respectively. The adjusted OR for subjects living in city centres compared to those living outside was 1.8 (95% CI 1.3-2.4; P = 0.0003). Both conventional risk factors for CVD and living in a city centre are independently associated with the presence of CAC in asymptomatic middle-aged subjects.