Cardiovascular disease and ABO blood-groups in Africans. Are blood-group A individuals at higher risk of ischemic disease?: A pilot study

Abstract

BackgroundSince the discovery of the ABO blood group system by Karl Landsteiner in 1901, several reports have suggested an important involvement of the ABO blood group system in the susceptibility to thrombosis. Assessing that non-O blood groups in particular A blood group confer a higher risk of venous and arterial thrombosis than group O.Epidemiologic data are typically not available for all racial and ethnics groups.The purpose of this pilot study was to identify a link between ABO blood group and ischemic disease (ID) in Africans, and to analyze whether A blood group individuals were at higher risk of ischemic disease or not.MethodsA total of 299 medical records of patients over a three-year period admitted to the cardiology and internal medicine department of military hospital of Ouakam in Senegal were reviewed. We studied data on age, gender, past history of hypertension, diabetes, smoking, sedentarism, obesity, hyperlipidemia, use of estrogen-progestin contraceptives and blood group distribution.In each blood group type, we evaluated the prevalence of ischemic and non-ischemic cardiovascular disease. The medical records were then stratified into two categories to evaluate incidence of ischemic disease: Group 1: Patients carrying blood-group A and Group 2: Patients carrying blood group non-A (O, AB and B).ResultsOf the 299 patients whose medical records were reviewed, 92 (30.8%) were carrying blood group A, 175 (58.5%) had blood group O, 13 (4.3%) had blood group B, and 19 (6.4%) had blood group AB.The diagnosis of ischemic disease (ID) was higher in patients with blood group A (61.2%) than in other blood groups, and the diagnosis of non-ischemic disease (NID) was higher in patients with blood group O (73.6%) compared to other groups. In patients with blood group B or AB compared to non-B or non-AB, respectively there was no statistically significant difference in ID incidence.Main risk factor for ID was smoking (56.5%), hypertension (18.4%) and diabetes (14.3%).In our study, there was no statistical difference between blood group A and non-A in myocardial infarction (MI) incidence (p = 0.09, 95% CI = 0.99–2.83) but a statistically significant difference between blood group A and non-A in stroke and coronary artery disease (CAD) incidence (p < 0.0001, 95% CI = 1.80–3.37 and p < 0.0001 95% CI = 1.82–3.41 respectively) was found.The incidence of ID in men was significantly higher in blood group A (95% CI = 2.26–4.57, p < 0.0001) compared with non-A group, while there was no statistically significant difference in women (p = 0.35). However, an overall effect was detected to be statistically significant regardless of gender (p < 0.0001).ConclusionOur study suggests an association between blood group A and ID in sub-Sahara Africans.In African countries, where most of health facilities are understaffed, more rigorous studies with a larger population are needed to give a high level of evidence to confirm this association in order to establish the need to be more aggressive in risk factor control in these individuals.

The relationship between platelet indices and ABO blood groups in healthy adults

“…In addition, other studies have suggested that the A blood group is an independent risk factor for coronary atherosclerosis and ischemic CVD. 2,32,33 In contrast to previous studies, MPV, a useful prognostic marker in patients with CAD and venous thrombosis, was found to be significantly lower in A blood group subjects than in B and AB blood group subjects (P = 0.024 and P = 0.007, respectively).…”

Metabolic health status and cardiovascular risk of different ABO blood group phenotypes

“…Anstee [29] reported that an association between blood group and CVD risk may only exist with non-O blood subtypes. Contrary to our findings, it was reported in a study performed in Senegal that the incidence of ischemic CVD in men was significantly higher in blood group A [23]. In the context of CVD in general, the level of risk of CVD associated with different ABO subtypes observed in our study, especially in blood group O, may not, in fact, differ from the study done in Senegal.…”

“…The level of CVD risk among females did not differ significantly between groups; however, among male subjects, the level of CVD risk in members of blood group O was significantly increased compared to non-O blood groups. This finding is consistent with prior studies reporting evidence of an association between ABO blood subtypes and risk of CVD [10,13,17,18,21,[23][24][25][26][27]. However, there is inconsistency in these prior findings as to which ABO blood subtype is at greater risk of CVD.…”

“…This implies that no blood group in the studied sample was more or less metabolically unhealthy than another. Many studies have revealed possible associations between various diseases, especially cardio-metabolic diseases, and the ABO blood groups, but the reasons for such an association remain controversial [8,10,22,23]. The present study revealed that the level of CVD risk for blood groups A and B was significantly lower compared with that of the O group.…”

“…However, there is inconsistency in these prior findings as to which ABO blood subtype is at greater risk of CVD. Some studies [10,13,21] have reported that individuals with blood group O were at highest risk for CVD, but this was not replicated in other studies [17,18,[23][24][25][26][27].…”