title: Ethnicity Modifies Associations between Cardiovascular Risk Factors and Disease Severity in Parallel Dutch and Singapore Coronary Cohorts.
abstract: BACKGROUND
  In 2020 the largest number of patients with coronary artery disease (CAD) will be found in Asia. Published epidemiological and clinical reports are overwhelmingly derived from western (White) cohorts and data from Asia are scant. We compared CAD severity and all-cause mortality among 4 of the world's most populous ethnicities: Whites, Chinese, Indians and Malays.
  
  
  METHODS
  The UNIted CORoNary cohort (UNICORN) simultaneously enrolled parallel populations of consecutive patients undergoing coronary angiography or intervention for suspected CAD in the Netherlands and Singapore. Using multivariable ordinal regression, we investigated the independent association of ethnicity with CAD severity and interactions between risk factors and ethnicity on CAD severity. Also, we compared all-cause mortality among the ethnic groups using multivariable Cox regression analysis.
  
  
  RESULTS
  We included 1,759 White, 685 Chinese, 201 Indian and 224 Malay patients undergoing coronary angiography. We found distinct inter-ethnic differences in cardiovascular risk factors. Furthermore, the associations of gender and diabetes with severity of CAD were significantly stronger in Chinese than Whites. Chinese (OR 1.3 [1.1-1.7], p = 0.008) and Malay (OR 1.9 [1.4-2.6], p<0.001) ethnicity were independently associated with more severe CAD as compared to White ethnicity. Strikingly, when stratified for diabetes status, we found a significant association of all three Asian ethnic groups as compared to White ethnicity with more severe CAD among diabetics, but not in non-diabetics. Crude all-cause mortality did not differ, but when adjusted for covariates mortality was higher in Malays than the other ethnic groups.
  
  
  CONCLUSIONS
  In this population of individuals undergoing coronary angiography, ethnicity is independently associated with the severity of CAD and modifies the strength of association between certain risk factors and CAD severity. Furthermore, mortality differs among ethnic groups. Our data provide insight in inter-ethnic differences in CAD risk factors, CAD severity and mortality.
authors.affiliation: Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands; The Netherlands Heart Institute (ICIN), Utrecht, The Netherlands.
authors.forename: Crystel M
authors.initials: CM
authors.lastname: Gijsberts
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore.
authors.forename: Aruni
authors.initials: A
authors.lastname: Seneviratna
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore.
authors.forename: Leonardo P
authors.initials: LP
authors.lastname: de Carvalho
authors.affiliation: Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Hester M
authors.initials: HM
authors.lastname: den Ruijter
authors.affiliation: Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Puwalani
authors.initials: P
authors.lastname: Vidanapthirana
authors.affiliation: Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Sorokin
authors.affiliation: Cardiology Department, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Pieter
authors.initials: P
authors.lastname: Stella
authors.affiliation: Cardiology Department, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Pierfrancesco
authors.initials: P
authors.lastname: Agostoni
authors.affiliation: Cardiology Department, University Medical Center Utrecht, Utrecht, The Netherlands; Durrer Center for Cardiogenetic Research, ICIN-Netherlands Heart Institute, Utrecht, The Netherlands; Institute of Cardiovascular Science, faculty of Population Health Sciences, University College London, London, United Kingdom.
authors.forename: Folkert W
authors.initials: FW
authors.lastname: Asselbergs
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore; Cardiovascular Research Institute (CVRI), National University Heart Centre (NUHCS), National University Health System, Singapore, Singapore.
authors.forename: A Mark
authors.initials: AM
authors.lastname: Richards
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore.
authors.forename: Adrian F
authors.initials: AF
authors.lastname: Low
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore.
authors.forename: Chi-Hang
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore.
authors.forename: Huay Cheem
authors.initials: HC
authors.lastname: Tan
authors.affiliation: Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Imo E
authors.initials: IE
authors.lastname: Hoefer
authors.affiliation: Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: Pasterkamp
authors.affiliation: Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands; The Netherlands Heart Institute (ICIN), Utrecht, The Netherlands; Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Cardiovascular Research Institute (CVRI), National University Heart Centre (NUHCS), National University Health System, Singapore, Singapore.
authors.forename: Dominique P V
authors.initials: DP
authors.lastname: de Kleijn
authors.affiliation: Cardiac Department, National University Heart Centre, National University Hospital, Singapore, Singapore; Cardiovascular Research Institute (CVRI), National University Heart Centre (NUHCS), National University Health System, Singapore, Singapore.
authors.forename: Mark Y
authors.initials: MY
authors.lastname: Chan
mesh_terms: D000368:Aged; D044466:Asian People; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000208:ethnology / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology / Q000208:ethnology; D011446:Prospective Studies; D012720:Severity of Illness Index; D012846:Singapore / Q000453:epidemiology / Q000208:ethnology; D044465:White People