Summary of studies and their associations
| No | Author (year) | Study design | Types of allergy | Purpose | Sample size and group comparison | Subjects characteristics | Association with ABO blood groups |
| 1 | Falsarella et al
25
Country: Brazil Year: 2011 | Case control | Allergic rhinitis | To determine if ABO phenotypes are associated with allergic rhinitis. | 168 patients and 168 controls | Age: 18–85 years, patients matched by age and gender with controls | The O phenotype was associated with susceptibility to allergic rhinitis for men but not for women (p=0.016; OR= 1.735; 95% CI 1.127 to 2.673). |
| 2 | Hamad26
Country: Iraq Year: 2016 | Cross sectional | Allergic rhinitis | To determine the prevalence of ABO blood groups and to investigate their association with allergic rhinitis and relate this association with genetics. | 109 | Age: 18–60 years (female and male) | Group O is the most common and has a high level of risk for developing allergic rhinitis (p=0.049). |
| 3 | Topno et al
27
Country: India Year: 2017 | Case control | Allergic rhinitis | To study the correlation of ABO phenotypes in patients with allergic rhinitis. | 100 patients and 100 controls | Outpatient department Ear,Nose and Throat (ENT) Age: 11–70 years, patients matched by age and gender with controls | The O blood group phenotype is associated with allergic rhinitis (OR 3.63, p=0.006). |
| 4 | Kauffmann et al
19
Country: France Year: 1996 | Cross sectional | Asthma | To assess the role of all three systems—Lewis, secretor and ABO—in lung function, wheezing and asthma. | 228 males | Age: 34–50 years, coal miners | Non-secretor subjects of blood group O have significantly lower lung function and higher prevalence of wheezing and asthma (p<0.01). |
| 5 | Ronchetti et al
20
Country: Italy Year: 2001 | Case control | Asthma | To analyse the joint phenotype ABO/secretor in a cohort of asthmatic children in an attempt to confirm the association observed in adult subjects. | 165 children (109 males and 56 females) 362 newborn infants as controls | Outpatients of a paediatric pulmonary clinic or patients who were admitted to a ward of the same clinic for acute respiratory episodes. Age: 1 month–15 years | O/non-secretor in asthmatic male children was higher than the controls (p<0.025). |
| 6 | Chen et al
28
Country: Taiwan Year: 2005 | Case control | Asthma | To analyse the histo-blood groups of ABO, Lewis and secretor in a cohort of asthmatic children in Taiwan. | 136 asthmatic children and 161 aged-matched controls | Age: 6–13 years | Blood group O/secretors were associated with childhood asthma (OR=2.7, 95% CI 1.126 to 6.033, p<0.02) |
| 7 | Saini and Yadav29
Country: India Year: 2014 | Case control | Asthma | To investigate the association of ABO and Rh (D) allele frequency in patients with asthma. | 180 subjects (120 asthmatics and 60 controls) | Patients matched by age, sex and socioeconomic status with controls | A possible association between blood group O and asthma prevalence was noted (p<0.05). |
| 8 | Yaro et al
30
Country: Nigeria Year: 2015 | Case control | Asthma | To explore the relationship of blood group type and susceptibility to asthma in Sokoto Metropolis, Nigeria. | 200 asthmatic patients and 100 adults (control group) | Individuals attending the Pulmonary Unit of Usmanu Danfodiyo University Teaching Hospital, Specialist Hospital and Maryam Abacha Women and Children Hospital, all in Sokoto metropolis, Nigeria | A possible association between blood group A and asthma susceptibility was noted (p<0.05). |
| 9 | Gangopadhyay et al
18
Country: India Year: 2006 | Cross sectional | Atopic dermatitis | To evaluate the relationship between atopic dermatitis and the ABO blood group. | 30 patients with atopic dermatitis | Patients attending the Dermatology Outpatient Department (OPD) of NRS Medical College, Kolkata, over a period of 1 year Age: 6 month–65 years | Blood group O with atopic dermatitis among patients is less prevalent than among controls (p<0.05). Blood group B is the most prevalent in patients with atopic dermatitis, followed by blood group A. |
| 10 | Abid33
Country: Pakistan Year: 2015 | Cross sectional | Atopic dermatitis | To determine the prevalence of ABO blood groups and to investigate their association with dust, pollen and skin allergy. | 123 young adults (males and females) | Age: 18–21 years | Blood group B is most common and has a high risk level for developing allergies (p=0.0007774). |
| 11 | Brachtel et al
34
Country: Germany Year: 1979 | Case control | Atopy | To assess the association of atopic disease with blood group with reference to a new population sample and to include polymorphic systems. | 239 patients 151 controls | Outpatients of the Dermatological Clinic of the University of Mainz | Higher susceptibility of individuals with blood groups A and B to atopic diseases such as rhinitis, bronchial asthma, dermatitis and many more. |