ABO blood group and risk of coronary heart disease in two prospective cohort studies

ABO Blood Group as a Model for Platelet Glycan Modification in Arterial Thrombosis

ABO blood groups have long been associated with cardiovascular disease, thrombosis, and acute coronary syndromes. Many studies over the years have shown type O blood group to be associated with lower risk of cardiovascular disease than non-type O blood groups. However, the mechanisms underlying this association remain unclear. Although ABO blood group is associated with variations in concentrations of circulating von Willebrand Factor and other endothelial cell adhesion molecules, ABO antigens are also present on several platelet surface glycoproteins and glycosphingolipids. As we highlight in this platelet-centric review, these glycomic modifications may affect platelet function in arterial thrombosis. More broadly, improving our understanding of the role of platelet glycan modifications in acute coronary syndromes may inform future diagnostics and therapeutics for cardiovascular diseases.

Novel genes in LDL metabolism--a comprehensive overview

PURPOSE OF REVIEW

To summarize recent findings from genome-wide association studies (GWAS), whole-exome sequencing of patients with familial hypercholesterolemia and 'exome chip' studies pointing to novel genes in LDL metabolism.

RECENT FINDINGS

The genetic loci for ATP-binding cassette transporters G5 and G8, Niemann-Pick C1-Like protein 1, sortilin-1, ABO blood-group glycosyltransferases, myosin regulatory light chain-interacting protein and cholesterol 7α-hydroxylase have all consistently been associated with LDL cholesterol levels and/or coronary artery disease in GWAS. Whole-exome sequencing and 'exome chip' studies have additionally suggested several novel genes in LDL metabolism including insulin-induced gene 2, signal transducing adaptor family member 1, lysosomal acid lipase A, patatin-like phospholipase domain-containing protein 5 and transmembrane 6 superfamily member 2. Most of these findings still require independent replications and/or functional studies to confirm the exact role in LDL metabolism and the clinical implications for human health.

SUMMARY

GWAS, exome sequencing studies, and recently 'exome chip' studies have suggested several novel genes with effects on LDL cholesterol. Novel genes in LDL metabolism will improve our understanding of mechanisms in LDL metabolism, and may lead to the identification of new drug targets to reduce LDL cholesterol levels.

Relationship of ABO Blood Type on Rotator Cuff Tears

BACKGROUND

ABO blood groups are associated with various diseases. A relationship between Achilles tendon ruptures and blood type O has been reported, although its pathogenesis was not clear. To the best of our knowledge, there is no published study describing the relationship between blood type and rotator cuff tendon tears.

OBJECTIVE

To determine whether patients with rotator cuff tear had a greater prevalence of blood type O than those without rotator cuff tear.

DESIGN

A cross-sectional study.

SETTING

Research hospital outpatient evaluation.

PARTICIPANTS

A total of 316 subjects with shoulder pain were included and divided into "tear" and "no-tear" groups according to ultrasonographic examination.

MAIN OUTCOME MEASURES

ABO blood group, gender, dominant arm, smoking history, trauma history, and age were compared between the 2 groups and the odds ratios of these factors were evaluated by logistic regression.

RESULTS

The tear group (38.6%) had more instances of blood type O than the healthy population (27.2%; P = .002). The adjusted odds ratio for rotator cuff tear for blood type O to non-O was 2.38 (95% confidence interval 1.28-4.42). The odds ratios for rotator cuff tears for smoking, major trauma history, minor trauma history, and age were 2.08, 3.11, 2.29, and 1.06, respectively.

CONCLUSION

Patients with rotator cuff tears were more likely to have blood type O. The odds ratios of factors for rotator cuff tears were high in the following order: major trauma history, blood type O, minor trauma history, and age.

ABO blood group in relation to plasma lipids and proprotein convertase subtilisin/kexin type 9

BACKGROUND AND AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9), a newly-identified member that plays an essential role in cholesterol homeostasis and holds decent promise for hyperlipidemia and coronary artery disease (CAD) treatment. However, the determining factors of PCSK9 are not well-characterized. It is well established that ABO blood group is associated with cholesterol metabolism. Therefore, the relationship between ABO blood groups and plasma PCSK9 level was examined.

METHODS AND RESULTS

A group of 507 consecutive patients undergoing diagnostic or interventional coronary angiography were enrolled in this cross-sectional study. The baseline clinical characteristics were collected, and the plasma PCSK9 levels were determined using ELISA. As a result, subjects of non-O type had higher levels of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), non high density lipoprotein cholesterol (NHDL-C), apolipoprotein B (apo B), and PCSK9 compared with that of O type (p < 0.05, all). PCSK9 levels were significantly and positively related to TC, LDL, NHDL-C, and apo B (r = 0.253, p < 0.001; r = 0.262, p < 0.001; r = 0.215, p < 0.001; r = 0.187, p < 0.001; respectively). Multivariable regression analysis revealed that ABO group was significantly and independently associated with PCSK9 level (β = 7.91, p = 0.009). Additionally, mediation analysis indicated that ≈8%-19% of the effect of ABO blood group on PCSK9 levels was mediated by TC, LDL-C or NHDL-C levels.

CONCLUSIONS

These data firstly suggested that the ABO blood group might be a significant determinant factor for plasma PCSK9 level. It is also possible that the observed association between PCSK9 and ABO blood group might be in part involved in their CAD susceptibility.

ABO and Rhesus blood groups and risk of type 2 diabetes: evidence from the large E3N cohort study

AIMS/HYPOTHESIS

The objective of this study was to evaluate the relationship of ABO blood type (A, B, AB and O), Rhesus factor (positive or negative) and a combination of the two (ABO × Rhesus) with type 2 diabetes mellitus risk.

METHODS

In total, 82,104 women from the large prospective E3N cohort were followed between 1990 and 2008. Multivariate Cox regression models were used to estimate HRs and 95% CIs.

RESULTS

Those with either the A (HR 1.10 [95% CI 1.02, 1.18]) or B (HR 1.21 [95% CI 1.07, 1.36]) group were at increased risk of type 2 diabetes mellitus compared with those with the O group. The association with the AB group did not reach statistical significance (HR 1.17 [95% CI 0.99, 1.39]). There was no difference in type 2 diabetes mellitus risk between Rhesus positive and negative groups (HR 0.96 [95% CI 0.88, 1.05]). When the universal donors (O(-)) were taken as the reference category, we observed an increased risk for both A(+) (HR 1.17 [95% CI 1.02, 1.35]) and A(-) (HR 1.22 [95% CI 1.03, 1.45]) individuals. The greatest increase in risk was seen for those with the B(+) blood group (HR 1.35 [95% CI 1.13, 1.60]). We also observed a greater type 2 diabetes mellitus risk for those with the AB(+) group (HR 1.26 [95% CI 1.02, 1.57]). Adjustment for fasting plasma glucose and lipid concentrations in a case-control subsample did not alter the associations.

CONCLUSIONS/INTERPRETATION

This study suggests that people with the O blood type have a lower risk of developing type 2 diabetes mellitus. Therefore, blood group should be investigated in future clinical and epidemiological studies on diabetes, and further pathophysiological research is needed to determine why individuals with blood type O have a lower risk of type 2 diabetes mellitus.

Genetics of coronary artery disease: an update

In 2007, the first genetic risk variant, 9p21, was simultaneously discovered by two independent groups. 9p21 increases the risk of coronary artery disease in individuals with premature heart disease by twofold, and in the overall population the heterozygote is associated with a 25% increased risk and the homozygote with a 50% increased risk. It is of note that the risk mediated by 9p21 is independent of known risk factors. Since then, with the development of new technologies and the international consortium of CARDIoGRAM, there is now a total of 50 genetic risk variants confirmed and replicated for CAD. Of these 50, 35 mediate their risk by unknown mechanisms, indicating that the pathogenesis of atherosclerosis and myocardial infarction is due to additional factors as yet unknown. The role of genetic risk factors in the management of CAD is yet to be determined. Since many of them are independent of known risk factors, the genetic risk will in the future have to be incorporated into the guidelines, which recommend the target level of plasma LDL-C to be achieved based on the number of risk factors.

Hemostasis, cancer, and ABO blood group: the most recent evidence of association

Human ABO blood group antigens are expressed on the surface of red blood cells and a variety of human cells and tissues. However, an increasingly number of studies show that the ABO blood group, in addition to its fundamental role in transfusion medicine and in several other disciplines, has a causal role in predisposing to several human diseases, including hemostasis and neoplastic disorders, which will be the focus of this narrative review.

Association of ABO blood types with the risk of in-stent restenosis

OBJECTIVES

To investigate the prevalence of in-stent restenosis (ISR) in patients with various ABO blood types.

METHODS

Clinical information from 150 patients with a confirmed diagnosis of ISR and 150 patients with a diagnosis of patent coronary stents in the secondary angiography was collected. Comprehensive demographic and laboratory data, including ABO and Rhesus blood groups, as well as comorbid conditions and vessel and stent characteristics, were recorded for each patient. The association of ABO blood groups with the risk of ISR before and after controlling for coronary risk factors was determined. Categorical data were analyzed with the Chi-square test and numerical values were analyzed with t-tests. Binary logistic regression models were constructed to compare type A and non-A for the frequency of risk factors.

RESULTS

A total of 392 stents were implanted in 300 patients. Two hundred and fourteen stents (54.6%) were patent and 178 stents (45.4%) were stenosed. Blood group A was significantly more common in the ISR group (43.3% vs. 28.7%, p=0.03). However, the frequencies of other blood types, as well as Rh antigen, were similar between the two groups. Triglyceride and low-density lipoproteins were the only significantly different variables (221 ± 198 mg/dL vs. 138 ± 76 mg/dL, p<0.001 and 108 ± 36 mg/dL vs. 96 ± 73 mg/dL, p=0.04, in type-A vs. non-A, respectively). After matching for coronary risk factors, there was no difference between A blood type patients and their controls.

CONCLUSION

ISR is significantly more prevalent in individuals with the type A blood group. However, this higher association is most likely due to higher atherogenic conditions in patients within this population.

Evolutionary aspects of ABO blood group in humans

The antigens of the ABO blood group system (A, B and H determinants) are complex carbohydrate molecules expressed on red blood cells and on a variety of other cell lines and tissues. Growing evidence is accumulating that ABO antigens, beyond their key role in transfusion medicine, may interplay with the pathogenesis of many human disorders, including infectious, cardiovascular and neoplastic diseases. In this narrative review, after succinct description of the current knowledge on the association between ABO blood groups and the most severe diseases, we aim to elucidate the particularly intriguing issue of the possible role of ABO system in successful aging. In particular, focus will be placed on studies evaluating the ABO phenotype in centenarians, the best human model of longevity.

Mortality and cancer in relation to ABO blood group phenotypes in the Golestan Cohort Study

BACKGROUND

A few studies have shown an association between blood group alleles and vascular disease, including atherosclerosis, which is thought to be due to the higher level of von Willebrand factor in these individuals and the association of blood group locus variants with plasma lipid levels. No large population-based study has explored this association with overall and cause-specific mortality.

METHODS

We aimed to study the association between ABO blood groups and overall and cause-specific mortality in the Golestan Cohort Study. In this cohort, 50,045 people 40- to 70-years old were recruited between 2004 and 2008, and followed annually to capture all incident cancers and deaths due to any cause. We used Cox regression models adjusted for age, sex, smoking, socioeconomic status, ethnicity, place of residence, education and opium use.

RESULTS

During a total of 346,708 person-years of follow-up (mean duration 6.9 years), 3,623 cohort participants died. Non-O blood groups were associated with significantly increased total mortality (hazard ratio (HR) = 1.09; 95% confidence interval (CI): 1.01 to 1.17) and cardiovascular disease mortality (HR = 1.15; 95% CI: 1.03 to 1.27). Blood group was not significantly associated with overall cancer mortality, but people with group A, group B, and all non-O blood groups combined had increased risk of incident gastric cancer. In a subgroup of cohort participants, we also showed higher plasma total cholesterol and low-density lipoprotein (LDL) in those with blood group A.

CONCLUSIONS

Non-O blood groups have an increased mortality, particularly due to cardiovascular diseases, which may be due to the effect of blood group alleles on blood biochemistry or their effect on von Willebrand factor and factor VIII levels.

The role of genetic risk factors in coronary artery disease

Genome-wide association studies for coronary artery disease utilizing the case control association study approach has identified 50 genetic risk variants associated with coronary artery disease or myocardial infarction. All of these genetic variants are of genome wide significance and replicated in an independent population. It is of note that 35 of these 50 genetic risk variants act through mechanisms as yet unknown. These findings have great implications for the pathogenesis of atherosclerosis, as well as new targets for the development of novel therapies for the prevention and treatment of CAD. The genetic variant PCSK9 has already led to the development of a monoclonal anti-body which is undergoing assessment in phases I, II, and III clinical trials. This therapy shows very promising results and since it increases removal of LDL-C, it is complementary to current statin therapy. Assessing the beneficial or deleterious effects of a lifelong exposure to a genetic risk variant (Mendelian randomization) will be an important adjunct to clinical trials.

The ABO blood group is an independent prognostic factor in patients with resected non-small cell lung cancer

Background

The ABO blood group is reported to be associated with the incidence and patient survival for several types of malignancies. We conducted a retrospective study to evaluate the prognostic significance of the ABO blood group in patients with resected non-small cell lung cancer (NSCLC).

Methods

A total of 333 patients (218 men and 115 women) with resected NSCLC were included in this study. In addition to age, sex, smoking status, preoperative serum carcinoembryonic antigen (CEA) level, operative procedure, histology of tumors, pathological stage (p-stage), and adjuvant therapy, the association between the ABO blood group and survival was explored.

Results

The 5-year overall and disease-free survival rates were 83.0% and 71.6% for blood group O, 67.2% and 62.3% for blood group A, 68.8% and 68.8% for blood group B and 69.2% and 65.3% for blood group AB, respectively. A multivariate analysis for overall survival showed the ABO blood group (group A vs. group O: HR 2.47, group AB vs. group O: HR 3.62) to be an independent significant prognostic factor, in addition to age, sex, smoking status, p-stage, and serum CEA level. A multivariate analysis for disease-free survival also showed the ABO blood group to be an independent significant prognostic factor.

Conclusions

The ABO blood group is an independent prognostic factor in patients with resected NSCLC. Studies of other larger cohorts are therefore needed to confirm the relationship between the ABO blood group and the prognosis among patients with resected NSCLC.

Relation of ABO blood groups to the severity of coronary atherosclerosis: an Gensini score assessment

OBJECTIVE

Although the study on the relationship between ABO blood groups and coronary atherosclerosis has a long history, few data is available regarding ABO to severity of coronary atherosclerosis in a large cohort study. Therefore, the present study aimed to investigate the relation of the ABO blood groups to the severity of coronary atherosclerosis assessed by Gensini score (GS) in a large Chinese cohort undergoing coronary angiography.

METHODS

A total of 2919 consecutive patients undergoing coronary angiography were enrolled, and their baseline characteristics and ABO blood groups were collected. The GS was calculated as 1st tertile (0-10), 2nd tertile (11-36), 3rd tertile (>36) according to angiographic results. The relation of the ABO blood groups to GS was investigated.

RESULTS

The frequency of blood group A was significantly higher in the upper GS tertiles (24.4% vs. 28.2% vs. 29.5%, p = 0.032). Multivariable linear regression analysis revealed that blood group A was independently associated with GS (β = 0.043, p = 0.017). Likewise, multivariable logistic regression analysis showed that group A remained significantly associated with mid-high GS (OR = 1.44, 95% CI 1.16-1.80, p = 0.001), and the group O was showed as a protective factor (OR = 0.77, 95% CI = 0.65-0.92, p = 0.004).

CONCLUSION

In this large Chinese cohort study, the data indicated that there was an association between ABO blood groups and the severity of coronary atherosclerosis. Moreover, the blood group A was an independent risk factor for serious coronary atherosclerosis.

Is ABO blood group truly a risk factor for thrombosis and adverse outcomes?

ABO blood type is one of the most readily available laboratory tests, and serves as a vital determinant in blood transfusion and organ transplantation. The ABO antigens are expressed not only on red blood cell membranes, determining the compatibility of transfusion, but also on the surface of other human cells, including epithelium, platelet and vascular endothelium, therefore extending the research into other involvements of cardiovascular disease and postoperative outcomes. ABO blood group has been recognized as a risk factor of venous thrombosis embolism since the 1960’s, effects now understood to be related to ABO dependent variations are procoagulant factor VIII (FVIII) and von Willebrand factor (vWF) levels. Levels of vWF, mostly genetically determined, are strongly associated with venous thromboembolism (VTE). It mediates platelet adhesion aggregation and stabilizes FVIII in plasma. Moreover, many studies have tried to identify the relationship between ABO blood types and ischemic heart disease. Unlike the clear and convincing associations between VTE and ABO blood type, the link between ABO blood type and ischemic heart disease is less consistent and may be confusing. Other than genetic factors, ischemic heart disease is strongly related to diet, race, lipid metabolism and economic status. In this review, we’ll summarize the data relating race and genetics, including ABO blood type, to VTE, ischemic heart disease and postoperative bleeding after cardiac surgery.

ABO blood type, factor VIII, and incident cognitive impairment in the REGARDS cohort

OBJECTIVE

To assess the relationships among ABO group, factor VIII (FVIII), and incident cognitive impairment in a large, prospective cohort study of black and white adults in the United States using a nested case-control design.

METHODS

Incident cognitive impairment was defined using cognitive domain tests over a mean follow-up of 3.4 years. ABO blood group was measured by genotyping in a nested case-control sample of 495 cases with cognitive impairment and 587 controls.

RESULTS

Those with blood group AB and those with higher FVIII had an increased risk of cognitive impairment, adjusting for age, race, region, and sex (respective odds ratios 1.82, 95% confidence interval [CI] 1.15-2.90; and 1.24, 95% CI 1.10-1.38 for 40 IU/dL higher FVIII). Mean FVIII was higher in those with blood type AB (142 IU/dL; 95% CI 119-165) compared with O (104 IU/dL; 95% CI 101-107), and FVIII mediated 18% of the association between AB group and incident cognitive impairment (95% CI for mediation -30% to 68%).

CONCLUSIONS

Blood group AB and higher FVIII were associated with increased incidence of cognitive impairment in this prospective study. The association of blood group AB with incident cognitive impairment was not significantly mediated by FVIII levels.

ABO blood group and thrombotic vascular disease

ABO blood group antigens are complex carbohydrate molecules expressed on red blood cells and a variety of tissues. The ABO blood type is implicated in the development of a number of human diseases and there is increasing evidence regarding its involvement in the pathogenesis of cardiovascular disorders, mainly through its effect on von Willebrand factor levels. In this review, after a brief analysis of the potential molecular mechanisms by which the blood group influences haemostasis, we focus on the clinical implications of such interaction. Overall, the literature data document the close relationship between venous thromboembolism (VTE) and non-O blood type, which is associated with an approximately two-fold increased risk of venous thrombosis. A supra-additive effect on VTE risk is observed when an inherited thrombophilic condition is associated with non-O blood group. A weaker association exists between non-O blood type and arterial thrombosis, which needs to be further investigated.

Factors associated with atrial fibrillation in rheumatic mitral stenosis

Background

Atrial fibrillation is a complication of mitral valve stenosis that causes several adverse neurologic outcomes. Our objective was to establish a mathematical model to predict the risk of atrial fibrillation in patients with mitral stenosis.

Methods

Of 819 patients with mitral stenosis who were screened, 603 were enrolled in the study and grouped according to whether they were in sinus rhythm or atrial fibrillation. Demographic, echocardiographic, and hemodynamic data were recorded. Logistic regression models were constructed to identify the relative risks for each contributing factor and calculate the probability of developing atrial fibrillation. Receiver operating characteristic curves were plotted.

Results

Two hundred (33%) patients had atrial fibrillation; this group was older, in a higher functional class, more likely to have suffered previous thromboembolic events, and had significantly larger left atrial diameters, lower ejection fractions, and lower left atrial appendage emptying flow velocity. The factors independently associated with atrial fibrillation were left atrial strain (odds ratio = 7.53 [4.47–12.69], p < 0.001), right atrial pressure (odds ratio = 1.09 [1.02–1.17], p = 0.01), age (odds ratio = 1.14 [1.05–1.25], p = 0.002), and ejection fraction (odds ratio = 0.92 [0.87–0.97], p = 0.003). The area under the curve for the combined receiver operating characteristic for this model was 0.90 ± 0.12.

Conclusion

Age, right atrial pressure, ejection fraction, and left atrial strain can be used to construct a mathematical model to predict the development of atrial fibrillation in rheumatic mitral stenosis.

ABO blood type and stroke risk: the REasons for Geographic And Racial Differences in Stroke Study

BACKGROUND

ABO blood type is an inherited trait associated with coagulation factor levels and vascular outcomes.

OBJECTIVES

To assess the association of blood type with stroke and whether blood type contributes to racial disparities in stroke in the United States.

PATIENTS AND METHODS

The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study recruited 30 239 participants between 2003 and 2007. Using a case-cohort design, blood type was genotyped in 646 participants with stroke and a 1104-participant cohort random sample. Cox models that adjusted for Framingham stroke risk factors were used to assess the association of blood type with stroke.

RESULTS

During 5.8 years of follow-up, blood types A or B vs. type O were not associated with stroke. Blood type AB vs. O was associated with an increased risk of stroke (adjusted hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.01-3.30). The association of blood type AB vs. O was greater in those without diabetes (adjusted HR 3.33, 95% CI 1.61-6.88) than those with diabetes (adjusted HR 0.49, 95% CI 0.17-1.44) (P interaction = 0.02). Factor VIII levels accounted for 60% (95% CI 11%-98%) of the association of AB blood type and stroke risk.

CONCLUSION

Blood type AB is associated with an increased risk of stroke that is not attenuated by conventional stroke risk factors, and factor VIII levels were associated with 60% of the association. While blood type AB is rare in the US population, it is a significant stroke risk factor and may play an important role in stroke risk in these individuals.

ABO blood type A is associated with increased risk of ARDS in whites following both major trauma and severe sepsis

BACKGROUND

ABO glycosyltransferases catalyze antigen modifications on various glycans and glycoproteins and determine the ABO blood types. Blood type A has been associated with increased risk of vascular diseases and differential circulating levels of proteins related to inflammation and endothelial function. The objective of this study was to determine the association of ABO blood types with ARDS risk in patients with major trauma and severe sepsis.

METHODS

We conducted prospective cohort studies in two populations at an urban tertiary referral, level I trauma center. Critically ill patients (n 5 732) presenting after major trauma were followed for 5 days for ARDS development. Additionally, 976 medical patients with severe sepsis were followed for 5 days for ARDS. Multivariable logistic regression was used to adjust for confounders.

RESULTS

ARDS developed in 197 of the 732 trauma patients (27%). Blood type A was associated with increased ARDS risk among whites (37% vs 24%; adjusted OR, 1.88; 95% CI, 1.14-3.12; P 5 .014), but not blacks (adjusted OR, 0.61; 95% CI, 0.33-1.13; P=.114). ARDS developed in 222 of the 976 patients with severe sepsis (23%). Blood type A was also associated with an increased ARDS risk among whites (31% vs 21%; adjusted OR, 1.67; 95% CI, 1.08-2.59; P=.021) but, again, not among blacks (adjusted OR, 1.17; 95% CI, 0.59-2.33; P=.652).

CONCLUSIONS

Blood type A is associated with an increased risk of ARDS in white patients with major trauma and severe sepsis. These results suggest a role for ABO glycans and glycosyltransferases in ARDS susceptibility.

ABO blood group: old dogma, new perspectives

Human blood group antigens are glycoproteins and glycolipids expressed on the surface of red blood cells and a variety of human tissues, including the epithelium, sensory neurons, platelets and the vascular endothelium. Accumulating evidence indicate that ABO blood type is implicated in the development of a number of human diseases, including cardiovascular and neoplastic disorders. In this review, beside its physiologic role in immunohematology and transfusion medicine, we summarize the current knowledge on the association between the ABO blood group and the risk of developing thrombotic events and cancers.

Analysis of circulating cholesterol levels as a mediator of an association between ABO blood group and coronary heart disease

BACKGROUND

Non-O type of ABO blood group has been associated with a predisposition to coronary heart disease. It is thought that this association is partly mediated by increased cholesterol levels in non-O-type individuals. In this study, we sought to estimate the mediation effect size.

METHODS AND RESULTS

In a group of individuals (n=6476) undergoing coronary angiography, we detected associations of non-O type with significant coronary artery disease with >50% stenosis in ≥1 coronary arteries (odds ratio, 1.24; 95% confidence interval, 1.10-1.39; P=2.6×10(-4)) and with prevalent or incident myocardial infarction (odds ratio, 1.22; 95% confidence interval, 1.09-1.37; P=1.2×10(-3)). Subjects of non-O type had higher levels of total cholesterol, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol (mean [SEM] in mmol/L: 4.931[0.021], 3.041 [0.018], and 3.805 [0.020] in non-O type compared with 4.778 [0.026], 2.906 [0.021], and 3.669 [0.024] in O type; P=3.8×10(-7), P=1.5×10(-7), and P=3.1×10(-7), respectively). Mediation analyses indicated that 10% of the effect of non-O type on coronary artery disease susceptibility was mediated by increased low-density lipoprotein cholesterol level (P=7.8×10(-4)) and that 11% of the effect of non-O type on myocardial infarction risk was mediated by raised low-density lipoprotein cholesterol level (P=2.0×10(-3)).

CONCLUSIONS

In a model in which it is presumed that cholesterol is a mediator of the associations of ABO group with coronary artery disease and myocardial infarction, around 10% of the effect of non-O type on coronary artery disease and myocardial infarction susceptibility was mediated by its influence on low-density lipoprotein cholesterol level.

The association of ABO blood groups with extent of coronary atherosclerosis in Croatian patients suffering from chronic coronary artery disease

Aim:

The aim of study was to: 1) examine the relationship between ABO blood groups and extent of coronary atherosclerosis in patients with chronic coronary artery disease (CAD), 2) compare ABO blood groups distribution in CAD patients and general population, 3) examine possible differences in traditional risk factors frequency in CAD patients with different ABO blood groups.

Materials and methods:

In the 646 chronic CAD patients (72.4% males) coronary angiograms were scored by quantitative assessment using multiple angiographic scoring system, Traditional risk factors were self reported or measured by standard methods. ABO blood distribution of patients was compared with group of 651 healthy blood donors (74.6% males).

Results:

Among all ABO blood group patients there was no significant difference between the extent of coronary atherosclerosis with regard to all the three scoring systems: number of affected coronary arteries (P = 0.857), Gensini score (P = 0.818), and number of segments narrowed > 50% (P = 0.781). There was no significant difference in ABO blood group distribution between CAD patients and healthy blood donors. Among CAD patients, men with blood group AB were significantly younger than their pairs with non-AB blood groups (P = 0.008). Among CAD patients with AB blood group, males < 50 yrs were significantly overrepresented when compared with the non-AB groups (P = 0.003).

Conclusions:

No association between ABO blood groups and the extent of coronary atherosclerosis in Croatian CAD patients is observed. Observation that AB blood group might possibly identify Croatian males at risk to develop the premature CAD has to be tested in larger cohort of patients.

A model-based 'varimax' sampling strategy for a heterogeneous population

BACKGROUND AND AIMS

Sampling strategies are planned to enhance the homogeneity of a sample, hence to minimize confounding errors. A sampling strategy was developed to minimize the variation within population groups. Karachi, the largest urban agglomeration in Pakistan, was used as a model population.

SUBJECTS AND METHODS

Blood groups ABO and Rh factor were determined for 3000 unrelated individuals selected through simple random sampling. Among them five population groups, namely Balochi, Muhajir, Pathan, Punjabi and Sindhi, based on paternal ethnicity were identified. An index was designed to measure the proportion of admixture at parental and grandparental levels. Population models based on index score were proposed. For validation, 175 individuals selected through stratified random sampling were genotyped for the three STR loci CSF1PO, TPOX and TH01.

RESULTS

ANOVA showed significant differences across the population groups for blood groups and STR loci distribution. Gene diversity was higher across the sub-population model than in the agglomerated population. At parental level gene diversities are significantly higher across No admixture models than Admixture models. At grandparental level the difference was not significant.

CONCLUSION

A sub-population model with no admixture at parental level was justified for sampling the heterogeneous population of Karachi.

Erythrocyte-bound apolipoprotein B in relation to atherosclerosis, serum lipids and ABO blood group

Introduction

Erythrocytes carry apolipoprotein B on their membrane, but the determining factors of erythrocyte-bound apolipoprotein B (ery-apoB) are unknown. We aimed to explore the determinants of ery-apoB to gain more insight into potential mechanisms.

Methods

Subjects with and without CVD were included (N = 398). Ery-apoB was measured on fresh whole blood samples using flow cytometry. Subjects with ery-apoB levels ≤0.20 a.u. were considered deficient. Carotid intima media thickness (CIMT) was determined as a measure of (subclinical) atherosclerosis.

Results

Mean ery-apoB value was 23.2% lower in subjects with increased CIMT (0.80±0.09 mm, N = 140) compared to subjects with a normal CIMT (0.57±0.08 mm, N = 258) (P = 0.007, adjusted P<0.001). CIMT and ery-apoB were inversely correlated (Spearman’s r: –0.116, P = 0.021). A total of 55 subjects (13.6%) were considered ery-apoB deficient, which was associated with a medical history of CVD (OR: 1.86, 95% CI 1.04–3.33; adjusted OR: 1.55; 95% CI 0.85–2.82). Discontinuation of statins in 54 subjects did not influence ery-apoB values despite a 58.4% increase in serum apolipoprotein B. Subjects with blood group O had significantly higher ery-apoB values (1.56±0.94 a.u.) when compared to subjects with blood group A (0.89±1.15 a.u), blood group B (0.73±0.1.12 a.u.) or blood group AB (0.69±0.69 a.u.) (P-ANOVA = 0.002).

Conclusion

Absence or very low values of ery-apoB are associated with clinical and subclinical atherosclerosis. While serum apolipoprotein B is not associated with ery-apoB, the ABO blood group seems to be a significant determinant.

Prakriti (Ayurvedic concept of constitution) and variations in platelet aggregation

Background

Ayurveda, the Indian traditional system of medicine describes a unique concept “prakriti”, genetically determined, categorising the population into several subgroups based on phenotypic characters like appearance, temperament and habits. The concept is claimed to be useful in predicting an individual’s susceptibility to a particular disease, prognosis of that illness and selection of therapy. The present study was carried out to study if the platelet aggregatory response and its inhibition by aspirin varied in the different prakriti subtypes.

Methods

After obtaining Institutional Ethics Committee permission, normal healthy individuals of either sex between the age group 18 to 30 years were recruited in the study. Their prakriti evaluation was done using a standardized validated questionnaire (TNMC Prakriti 2004). Their Platelet Rich Plasma was incubated with either aspirin [2.5micro-mole (μM) and 5μM] or distilled water as control for three minutes after which the aggregatory response to 5μM Adenosine Diphosphate (ADP) was measured over a period of 7 minutes.

Results

We observed that in the study population of normal healthy participants (n= 137), ADP-induced maximal platelet aggregation (MPA) was highest among the Vata-pitta prakriti individuals [Median (range), 83.33% (52.33-96)] as compared to the other prakriti types and these individuals responded better to lower dose of aspirin compared to other prakriti types.

Conclusions

Our results suggest that identifying the prakriti may help in individualising therapy or predicting proneness to a disease.

ABO Blood Groups and Cardiovascular Diseases

ABO blood groups have been associated with various disease phenotypes, particularly cardiovascular diseases. Cardiovascular diseases are the most common causes of death in developed countries and their prevalence rate is rapidly growing in developing countries. There have been substantial historical associations between non-O blood group status and an increase in some cardiovascular disorders. Recent GWASs have identified ABO as a locus for thrombosis, myocardial infarction, and multiple cardiovascular risk biomarkers, refocusing attention on mechanisms and potential for clinical advances. As we highlight in this paper, more recent work is beginning to probe the molecular basis of the disease associations observed in these observational studies. Advances in our understanding of the physiologic importance of various endothelial and platelet-derived circulating glycoproteins are elucidating the mechanisms through which the ABO blood group may determine overall cardiovascular disease risk. The role of blood group antigens in the pathogenesis of various cardiovascular disorders remains a fascinating subject with potential to lead to novel therapeutics and prognostics and to reduce the global burden of cardiovascular diseases.