Impact of different blood groups on body mass index and blood pressure

Obesity is considered as a public health problem that affects all age groups in the population. Genetic factors are considered as one of the non-modi(cid:977)iable risk factors, causing obesity. Hypertension is a chronic medical condition that is associated with vague symptoms. The ABO blood type is one of the fun-damental genetic factors that can give important information for early detection of risky population. This study aimed to evaluate the impact of different blood groups on body mass index and blood pressure. The design of this study is a cross-sectional study, included 250 participants (144 males and 106 females), aged between 18-70 years were selected from the population of Al-Najaf Governorate, Iraq, through a period which extends from October 2019 to February 2020. The blood groups were determined for each participant; blood pressure and body mass index were also measured. The results of a current study revealed that from this 250 participants there was 115 were obese person, 82 were overweight person, 51 were normal weight, and 2 were underweight persons. In the obese group, the blood group B has the highest percentage (45.2% ) followed by blood group A and O that were found to have the same percentage (22.6%), while the blood group AB has the lower percentage (9.6%). On the other hand, there was no signi(cid:977)icant relationship between hypertension and ABO blood groups.


INTRODUCTION
One of the most developing problems in the world is obesity; many of the studies showed that obesity occurs in about one third or more of the populations (Ng et al., 2013). Obesity can be de ined as the accumulation of the abnormal or excessive amount of fats in the body and causing many medical problems in the body. Body mass index (BMI) is considered as a simple index for obesity and when the body mass index of a person is equal or greater than 30 kg/m 2 , in this case, considered as an obese person (WHO, 2006). For obesity and overweight, there are many causes. Still, the most common causes are overeating of food or eating food with high fats and calories, reduction of physical activity, little or excess sleep both cases cause many of hormonal changes, and these changes cause many of the effects on the appetite and metabolism in addition to genetic factors . The obesity is considered as a risk factor for many of disease such as particular type of cancer (Polednak, 2008), cardiovascular disease (Flint et al., 2010), and type 2 Diabetes (Lozano et al., 2010).
Hypertension is a signi icant health problem and one of the most common life-threatening noncommunicable disease, that is caused by many fac-     (Gyton and Hall, 2011).
Blood types of blood groups are classi ied into four groups by depending on the presence or absence of inherited antigenic substances on the surface of red blood cells. These antigenic substances are different according to the blood group system so that they may be proteins, carbohydrate, glycoproteins or glycolipids (Cusack et al., 2013). These antigens (in addition to red blood cells) are also found in other different cells, such as platelets, endothelium and epithelium of vessels in addition to the saliva and other luids of the body (Hosoi, 2008). Landsteiner is the irst to discover of the ABO blood system in 1901, and this system is considered as the most important system and is found on chromosome 9 and encoded by gene 1 (Qadir and Malik, 2010).
The second type of blood group system is the Rhesus system. This system is important in the transfusion of blood in a human, antigen of this system or Rh factor called D. So when the person has Rh factor is called Rh-positive, while if the person does not have this factor called Rh negative (Qadir and Iqbal, 2018). The clinical importance of ABO blood type is extended outside transfusion reaction or solid organ transplantation, because different studies found that there are several associations between ABO blood groups and different disease, such as gastric cancer (Hajj et al., 2007), myocardial infarction in the presence of coronary artery atherosclerosis, Diabetes mellitus (Kamil et al., 2010), sexual matu-rity (Dai et al., 2014), breast cancer (Payandeh et al., 2015), hypertension (Hercegovac et al., 2017).
The present study aimed to evaluate the impact of different blood groups on the body mass index and blood pressure.

MATERIALS AND METHODS
The current study is a cross-sectional study involved 250 subjects (144 males and 106 females), ranging in age from 18 to70 years were selected from the population of Al-Najaf Governorate, Iraq, through a period which extends from October 2019 to February 2020. To calculate the body mass index (BMI), the participant's weight and height were measured by using weight and height scale. The participants were divided into four categories according to their body mass index: Underweight ( BMI< 18.5 kg/m 2 ), Normal (18.5-24.9 kg/m 2 ), Overweight (25-29.9 kg/m 2 ) and Obese (≥30 kg/m 2 ) (WHO, 2006). Blood pressure was measured by using a standard manual mercury sphygmomanometer in a sitting position. The participants were divided into three categories according to their blood pressure: Normal (<120/<80 mmHg), Prehypertension (120-139/80-89 mmHg) and Hypertension (≥140/≥90 mmHg) (Whelton et al., 2018). Some information was taken from every participant in this study such as name, age and according to their age participants divided into six categories: (15-24years; 25-34 years; 35-44 years, 45-54 years; 55-64 years, 65-74) and sex, besides, the blood group was determined for each one by standard methods using antigenantibody reaction and according to the blood groups the participant divided into four groups (A, B, AB and O blood group).

Statistical analysis
Statistical analysis was done by using SPSS (statistical package for social science) version 18. Using Frequency, percentage, chi-square test and P-value. When P value < 0.05 was considered signi icant (Daniel, 2013).  Also, the results of the study showed that there is a signi icant difference in the distribution of gender according to the type of blood groups (P-value =0.005), as shown in Table 3. Males with blood group O + (56) was the most common group, followed by males with blood group A + (44), then females having blood group O + (34), then males having blood group B + and females of blood groups A + and B + have the same numbers (25), while females with the AB + blood group has (21) subjects and males with blood group AB + has (11) subjects. Finally, males with blood groups B − and O − and females with blood group O − have the lowest numbers (6, 2 and 1), respectively.

RESULTS AND DISCUSSION
Finally, there are no signi icant differences in the distribution of blood pressure according to the type of blood groups (P-value = 0.518), as shown in Table 4 below.
Obesity is a chronic disease caused by a combination of many factors like genetic, environmental, metabolic, physiological and psychological factors.
In the current study, obese subjects have the highest numbers of participants followed by overweight, normal and underweight. Obesity (BMI≥30) was found in subjects with blood group B followed by O, A and AB (Table 1). These indings are com-patible with (Abdollahi et al., 2009;Chandra and Gupta, 2012;Rai and Sapkota, 2017). Their studies came up with the fact that that blood group B was more susceptible to obesity followed by O, A and AB.
Other studies (Siva et al., 2012;Jadhav et al., 2015) found that obesity was common in blood group O, while a study by (Jafari et al., 2012) showed that the prevalence of obesity occurs in blood group A and study by (Hercegovac et al., 2017) showed that subjects with AB blood group have the highest average value of BMI. While, studies done by (Aboel-Fetoh et al., 2016;Smith et al., 2018) showed no statistically signi icant association between obesity and blood groups. The results of the current study suggest that blood group B might be more predisposed genetically to obesity than other blood groups. Also, the obesity is considered to be an in lammatory disease (Faber et al., 2009) and some other studies suggest that the antigens of blood groups may have a regulatory role in in lammation (Liumbruno and Franchini, 2013) and this may be linked to obesity.
The results of the study showed that there is a significant difference in the distribution of age, according to the type of blood groups (P-value <0.05) ( Table 2). This outcome occurs because most of the participants are collected from Kufa university workers, and most of these workers lie at this age.
Study indings showed that there is a signi icant difference in the distribution of gender according to the type of blood (Table 3). Males have a higher number of participants than females. Males with blood group O + was the most common group, while female and male with AB + blood group was the less common group. These indings may occur because, in the Iraqi population, the blood group O was the most common group followed by A, B and AB (Jaff, 2010;Saleh and Abood, 2016). On the other hand, a study by (Smith et al., 2018) observed that there is no signi icant difference regarding the association of ABO blood group with gender.
Hypertension is one of the critical health problems, and many patients are unaware of this health issue Tassaduqe et al. (2004). In the current study, no signi icant difference was found in the distribution of blood pressure, according to the type of blood groups (Table 4). While, some other study found that blood group A was more susceptible to hypertension (Hercegovac et al., 2017). These differences may be attributed to the differences in local factors such as geographical factors; in addition to sample size.

CONCLUSIONS
In conclusion, our results suggest that the relative risk of obesity was found to be higher in blood group B, and the blood group B has the highest tendency to develop obesity than other groups.

Recommendations
More studies needed with increased sample size, in addition to different geographical areas and populations should be included.

Con lict of interest
The authors declared that they have no competing interests.

Financial support
The authors declare that they have no funding support for this study.