Comparison of coronary calcification among South Asians and Caucasians in the UK

Abstract

Most of the published studies have shown racial differences in the prevalence and severity of coronary artery calcification (CAC) [1–3]. Although individuals of South Asian origin (India, Pakistan, Sri Lanka, Nepal & Bangladesh) represent 20% of the world population and considered as one of the largest ethnic groups at risk of coronary heart disease (CHD), they are under-represented in studies investigating the presence of CAC [4,5]. Therefore, we compared the prevalence of CAC in Caucasians and South Asians who underwent electron beam computed tomography (EBCT) at the European Scanning Centre, London, UK. CAC score (CACS) was performed on an Imatron C300 Ultrafast EBCT scanner (GE Healthcare), using a standard method with calcium deposition scored according to Agatston method [6]. Demographic information and the presence of risk factors were abstracted from referral letters and questionnaires completed by the patients prior to their test. Individuals with previously documented CHD or chronic kidney disease were not included in the study. CACSwas assessed in 935 South Asians (739males and 196 females) and 13,501 Caucasians (10,232 males and 3269 females). Gender distribution between Caucasians and South Asians was similar (p= 0.1); conversely, the Caucasians group was older to its South Asians counterpart (52.8 ± 9.6 vs. 50.6 ± 10.3, respectively; p b 0.001); while on the other hand, South Asians appeared to have a higher prevalence of diabetes mellitus (17.5% vs. 4.3%; p b 0.0001). Interestingly, therewas no difference in the prevalence of smoking between the 2 groups (15% vs. 12.1%; p = 0.06), of hypertension (31.3% vs. 25.3%; p b 0.4), family history of CHD (22.8% vs. 16.1%; p = 0.3), and hyperlipidemia (24.5% vs. 17.3%; p = 0.3). The prevalence of CAC (CACS N 0) was similar between Caucasians and South Asians (50.9% vs. 50.8%; p= 0.9), although a statistically significant difference in the prevalence of CAC in South Asians N50 years should be noted (p= 0.01). South Asian males showed a higher mean CACS as compared to Caucasians (179.6 ± 545.1 vs. 144.1 ± 420.1; p= 0.03). Although, in malesb50 years, therewasno statistically significantlydifference inmean CACS between South Asians and Caucasians (36.1 ± 277.8 vs. 23.8 ± 104.2; p= 0.06), inmales N50 years old thedifference inmeanCACSwas significant (South Asians, 339.1 ± 702.9 vs. Caucasians 232.3 ± 528.7; p b 0.0001). On the other hand, no difference was observed in the mean CACS between South Asian and Caucasian females (South Asians 59.2 ± 224.9 vs. Caucasians 56.6 ± 219.2; p = 0.86). South Asian females b50 years and South Asian females N50 years had similar mean CACS compared to Caucasians. CACS subgroups for age, gender and racial subgroups are tabulated in Table 1. We observe that in South Asian males N50 years old, the mean CACS was significantly higher than the Caucasians (p b 0.0003) and there was significant difference in the proportion of the population in any CACS range (p= 0.01). South Asians seem more prone to extensive calcification, as South Asians had higher mean CACS than Caucasians in both sex and all age groups (Fig. 1). Furthermore, age seems to play an important