Hypertension is one of the leading causes of the global burden of disease in the world. As per the report by the NCD Risk Factor Collaboration (NCD-RisC) the number of people with hypertension globally in 2019 was over 1 billion and this number has doubled since 1990 1 . Being one of the major modifiable causes of premature death, it is one of WHO’s global targets for the prevention of non-communicable diseases2. The problem is compounded by the fact that though it is very common, readily detectable, usually easily treatable, it is most often asymptomatic and would more often than not lead to lethal complications if left untreated. Hypertension doubles the risk of cardiovascular diseases, including CHD, CHF, ischemic and haemorrhagic stroke, renal failure and peripheral arterial disease. Clinically, it can be defined as that level of blood pressure at which the institution of therapy reduces blood-pressure related morbidity and mortality 3. The risk of developing cardiovascular disease doubles for every 20 mmHg increase in systolic and 10 mmHg increase in diastolic blood pressure above normal. The recommended criteria for a diagnosis of hypertension are average awake blood pressure ≥135/85 mmHg and asleep blood pressure ≥ 120/75 mmHg, which approximates a clinic blood pressure of 140/90 mmHg   3. Modifiable risk factors for hypertension include unhealthy diets (excessive salt consumption, a diet high in saturated fat and trans fats, low intake of fruits and vegetables), physical inactivity, consumption of tobacco and alcohol, and being overweight or obese 4. Obesity and weight gain are strong independent risk factors for hypertension. However, apart from these modifiable risk factors, non-modifiable risk factors such as age, gender, ethnicity 5 and certain genetic factors have also been implicated indicating that the disease might be a form of polygenic disorder in which a single gene or combination of genes act in concert with environmental exposures to contribute to a rise in the blood pressure3.

Since its discovery by Karl Landsteiner in 1900, the ABO blood group system has been extensively investigated for its correlation with different diseases. This curiosity may partly stem from the fact that presence and absence of antigens in some blood types or their modifications at the genetic level (such as by deletions, inversions, insertions etc.) lead to antigenic changes which can result in alterations in both morphology and function of the RBCs which may cause the different blood types to associate with different diseases. In addition, apart from RBC membranes, blood group antigens can be found on leukocytes, certain tissues, plasma proteins, platelets, and various cell surface enzymes and in body fluids such as sweat, saliva, breast milk, seminal fluid, urine, gastric secretions, and amniotic fluid 6. Many studies postulate the association of the ABO blood group with various communicable diseases 8 and non-communicable7 diseases including cardiovascular diseases 9. Another important factor is that the ABO blood group antigens are permanent antigens i.e present for life and are easily detectable by simple laboratory investigations involving antigen-antibody reactions. This makes the identification of the various ABO blood groups among the population easy and affordable. If a positive association between the ABO blood group system and blood pressure can be established, it would allow the early detection and timely intervention for the prevention of hypertension among susceptible individuals thereby decreasing the burden of this disease on the world community. With this aim, the current study was conducted to ascertain an association between ABO blood group and blood pressure among the undergraduate students in Silchar Medical College & Hospital.

This cross-sectional study was conducted among 360 medical students in the Department of Physiology, Silchar Medical College, Silchar, Assam, during the period of October 2023 to September 2024.   The blood pressure was measured by mercury sphygmomanometer in the sitting position on the left arm. Two readings were obtained with an interval of 5 minutes in between and the average of these readings were considered. The appearance of the first Korotkoff’s sound was taken as the SBP and the disappearance of the same was taken as the DBP. Blood group was determined using the slide method where the subject’s blood (obtained under aseptic conditions) was treated with known anti-sera. In addition, Height in cm and weight in Kg were measured for estimation of the BMI. BMI was calculated by using the formula of Weight/(Height in mtrs)2 . The data collected was compiled using Microsoft Excel and analysed using the software SPSS.  A p-value of <0.05 was considered statistically significant.

The data of 360 students were collected and analyzed. The mean age of Students is 20.3 years with mean weight 60.225 Kg and mean height 164.2 cm.

From the above two graphs it is seen that, in our data 62% are male students while 32% are female.

Out of which 42% students have blood group O, 17% have blood group A, 32% have blood group B and 9% have blood group AB.

Table 1: Distribution of Gender in different blood groups

Most common blood group is blood group O: 67 (41.875%) students. The least common blood group among the students is AB blood group: 14 (8.75%) students. 

Table 2 : Distribution of Blood Groups in Different BMI

From the above table and graph, maximum 5 (3.125%) obesity was found in students with blood group B. There is no obesity found in blood groups A and AB. Students with blood group O were maximum (12) underweight. Maximum overweight (17) found in blood group O.

The chi-square statistic is 25.649 with Degrees of freedom: 15. The p-value is 0.0419. The result is thus statistically significant at p < 0.05

Table 3: Distribution of Blood Group with Systolic Blood Pressure

The above table shows that Group A has the highest percentage of prehypertension(42.86%) and Group O and Group B has the highest percentage (31.34% and 31.37%) of Stage 1 hypertension with group A has minimum percentage (7.14%). Stage 2 hypertension was seen maximum in AB blood group (14.29%). The chi-square statistic is 15.088 with Degrees of Freedom: 9. the p-value is 0.0885. The result is thus not statistically significant at p < .05.

Table 4: Distribution of Blood Group with Diastolic Blood Pressure

The above table shows that Group B has the highest percentage of prehypertension (43.14%) and Group AB has the highest percentage (14.29%) of Stage 1 hypertension while group B has minimum percentage (0.00%). Stage 2 hypertension was seen in B blood group (3.92%). The chi-square statistic is 41.651 with Degrees of Freedom: 18.  The p-value is 0.0012 which is statistically significant at p < .05.

Most common blood group in our study is blood group O: 67 (41.875%) students. The least common blood group among the students is AB blood group: 14 (8.75%) students. Maximum obesity: - 5 (3.125%) was found in students with blood group B. There was no obesity found in blood groups A and AB. Students with blood group O were maximum (12) underweight. Maximum overweight (17) found in blood group O.

Group A has the highest percentage of prehypertension(42.86%) and Group O and Group B has the highest percentage (31.34% and 31.37%) of Stage 1 hypertension with group A has minimum percentage (7.14%). Stage 2 hypertension was seen maximum in AB blood group (14.29%). However this was not found to be statistically significant.

Group B has the highest percentage of prehypertension (43.14%) and Group AB has the highest percentage (14.29%) of Stage 1 hypertension while group B has minimum percentage (0.00%). Stage 2 hypertension was seen maximum in B blood group (3.92%). This variation of diastolic BP among the different blood groups was found to be statistically significant.

In our study Blood group B individuals have a statistically significant inclination towards obesity and the development of pre-hypertension and hypertension (Diastolic). This is similar to the findings of a few other studies like that of Turki A, Alrasheed K, OmarB et al10. Hitesh Kumar K Solanki et al11 also share a similar finding  where they concluded that Blood group B has the highest tendency to be obese and develop both prehypertension and hypertension. However few studies like that of Siva KG et al12 differ in their findings on obesity where they concluded that blood group O were more prone to be obese.

Thus we can see from our study that most common blood group among students is Blood group O and the least common is AB. Blood group B individuals have a statistically significant inclination towards obesity and the development of both pre-hypertension and hypertension (Diastolic). However, systolic hypertension among the students did not have a statistically significant variation among  the different ABO blood groups

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