Coronary artery calcium distributions in older persons in the AGES-Reykjavik study
- 393 Downloads
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, R2 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, R2, 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.
KeywordsCoronary artery calcium Epidemiology Older persons Skewed distribution ZINB Statistical modelling
Coronary artery calcium
Coronary artery disease
Carotid intima medial thickness
High density lipoprotein
Transient ischemic attack
Zero inflated negative binomial
This work was supported by the National Institutes of Health (NIH) contract N01-AG-12100; the National Institute on Aging, in part by the Intramural Research Program; Hjartavernd (the Icelandic Heart Association); and the Althingi (the Icelandic Parliament).
Conflict of interest
The authors declare that they have no conflict of interest.
- 4.Kronmal RA, McClelland RL, Detrano R, Shea S, Lima JA, Cushman M, et al. Risk factors for the progression of coronary artery calcification in asymptomatic subjects: results from the multi-ethnic study of atherosclerosis (MESA). Circulation. 2007;115(21):2722–30. doi: 10.1161/circulationaha.106.674143.PubMedCrossRefGoogle Scholar
- 5.Hoff JA, Daviglus ML, Chomka EV, Krainik AJ, Sevrukov A, Kondos GT. Conventional coronary artery disease risk factors and coronary artery calcium detected by electron beam tomography in 30,908 healthy individuals. Ann Epidemiol. 2003;13(3):163–9. doi: 10.1016/s1047-2797(02)00277-6.PubMedCrossRefGoogle Scholar
- 9.Pletcher M, Tice J, Pignone M, McCulloch C, Callister T, Browner W. What does my patient’s coronary artery calcium score mean? Combining information from the coronary artery calcium score with information from conventional risk factors to estimate coronary heart disease risk. BMC Med. 2004;2(1):31.PubMedCrossRefGoogle Scholar
- 10.Budoff MJ, Nasir K, McClelland RL, Detrano R, Wong N, Blumenthal RS, et al. Coronary calcium predicts events better with absolute calcium scores than age-sex-race/ethnicity percentiles: MESA (Multi-Ethnic Study of Atherosclerosis). J Am Coll Cardiol. 2009;53(4):345–52. doi: 10.1016/j.jacc.2008.07.072.PubMedCrossRefGoogle Scholar
- 11.Greenland P, Bonow RO, Brundage BH, Budoff MJ, Eisenberg MJ, Grundy SM, et al. ACCF/AHA 2007 clinical expert consensus document on coronary artery calcium scoring by computed tomography in global cardiovascular risk assessment and in evaluation of patients with chest pain: a report of the American College of Cardiology Foundation Clinical Expert consensus task force (ACCF/AHA writing committee to update the 2000 expert consensus document on electron beam computed tomography) developed in collaboration with the society of atherosclerosis imaging and prevention and the society of cardiovascular computed tomography. J Am Coll Cardiol. 2007;49(3):378–402. doi: 10.1016/j.jacc.2006.10.001.PubMedCrossRefGoogle Scholar
- 13.Hardin JW, Hilbe JM. Generalized liner models and extensions, 2 edn. College Station: Stata Press; 2007.Google Scholar
- 15.O’Donnell CJ, Kavousi M, Smith AV, Kardia SLR, Feitosa MF, Hwang S-J, et al. Genome-wide association study for coronary artery calcification with follow-up in myocardial infarction/clinical perspective. Circulation. 2011;124(25):2855–64. doi: 10.1161/circulationaha.110.974899.PubMedCrossRefGoogle Scholar
- 17.Peinemann F, Moebus S, Dragano N, MÃ¶hlenkamp S, Lehmann N, Zeeb H et al. Secondhand Smoke Exposure and Coronary Artery Calcification among Nonsmoking Participants of a Population-Based Cohort. Environ Health Perspect. 2011;119(11).Google Scholar
- 21.Stata 11 help for zinb. 2011. http://www.stata.com/help.cgi?zinb. Accessed 3 June 2011.
- 22.SAS/ETS(R) 9.2 User’s Guide. 2011. http://support.sas.com/documentation/cdl/en/etsug/60372/HTML/default/viewer.htm#etsug_countreg_sect029.htm. Accessed 3 June 2011.
- 23.Regression Models for Count Data in R. 2011. http://cran.r-project.org/web/packages/pscl/vignettes/countreg.pdf. Accessed 3 June 2011.
- 28.Carr JJ, Nelson JC, Wong ND, McNitt-Gray M, Arad Y, Jacobs DR, et al. Calcified coronary artery plaque measurement with cardiac CT in population-based studies: standardized protocol of multi-ethnic study of atherosclerosis (MESA) and coronary artery risk development in young adults (CARDIA) study 1. Radiology. 2005;234(1):35–43. doi: 10.1148/radiol.2341040439.PubMedCrossRefGoogle Scholar
- 29.Jonsson H, Helgadottir GP, Aspelund T, Eiriksdottir G, Sigurdsson S, Ingvarsson T, et al. Hand osteoarthritis in older women is associated with carotid and coronary atherosclerosis: the AGES Reykjavik study. Ann Rheum Dis. 2009;68(11):1696–700. doi: 10.1136/ard.2008.096289.PubMedCrossRefGoogle Scholar
- 33.Robert R, Sokal FJR. Biometry. 3rd ed. New York: W.H. Freemann and Company; 1995.Google Scholar
- 35.Myers RH. Classical and modern regression with applications. 2nd ed. Belmont: Duxbury Press; 1990.Google Scholar
- 40.Statistics Iceland. Reykjavik. 2011. http://www.statice.is/. Accessed 28 June 2011.