It could all be down to your blood type

When Christopher was wheeled into the emergency room, it was clear he had lost a massive amount of blood. And the young medic on duty that day asked for a blood bag. The man on the gurney needed a blood transfusion. But as the fresh blood made its way through the man’s veins, the monitors began beeping in earnest. He was going into shock, and would later die. The medic would later learn that they gave the poor man the wrong blood type.

The upside to this scenario is that Christopher is a TV actor and that was a scene from an episode of the TV show Grey’s Anatomy. In the real world, they will make sure to know your blood type before they transfuse. But if it were to really happen, your body’s immune system would go into attack mode, attacking the donated blood cells. The medics call it a haemolytic transfusion reaction. And your kidneys could fail in the process, and you would get really sick. And if nothing was done quickly to remedy the situation, you would go into shock and die. What a way to go!

Do you know your blood type?

Besides avoiding the haemolytic drug reaction described above, there is now even more reason to know what your blood type is. Your blood group has other implications on your health. Although the medical community used to dismiss the idea, in recent years, studies have shown that there could be a link between blood groups and certain health conditions.

Your blood type and severity of coronavirus

The findings of a study published in the New England Journal of Medicine a week ago, attempts to explain the link between blood type and patient’s susceptibility to coronavirus. Patients with blood Type A were found to have a higher risk of respiratory failure when they contracted coronavirus. People with Type O blood have a lower risk of developing severe symptoms.

The study found a higher risk in blood group A than in other blood groups and a protective effect in blood group O as compared with other blood groups.

Findings also suggest that people with Type A blood had a 45 per cent higher risk of becoming infected than people with other blood types. People with Type O blood were just 65 per cent as likely to become infected as people with other blood types. There are four main blood types — A, B, AB and O.

The scientists analysed the genes of some 1980 patients with Covid-19 that had progressed to respiratory failure at seven hospitals in Italy and Spain and compared them to 2,205 people who were not sick.

They did a genome-wide association study, analysing the genetic map of the study subjects to find two DNA variations that were more common in the most severe patients.

Researchers tied variations in six genes to the likelihood of severe disease, including some that could have a role in how vulnerable people are to the virus. They also tied blood groups to possible risk.

The genetic analysis suggested that blood type might influence whether someone develops a severe case of the disease. 

This is just the most recent of many studies to determine whether genetics could play a role in susceptibility to the virus and while it does not prove a blood type connection, it confirms previous studies from China which attempted to suggest a link. 

In Wuhan, the epicentre of the Covid-19 outbreak, scientists performed two studies to investigate the link between blood type and coronavirus susceptibility and between blood type and the risk of contracting pneumonia caused by the coronavirus. 

The two studies reached a similar conclusion, that people with O blood type were less likely to get Covid-19 or have a severe infection.

However, despite the established link, the studies do not say that people with blood group O do not carry the risk of infection with the coronavirus.

Dr Joseph Maina, a consultant haematoligist in Nairobi warns that while the link is likely, it would be subtle and minor and no matter the blood group, one should take the necessary precautions.

Dr Simon Nyangena concurs. “Blood groups may have an impact but just a minor one. Coronavirus uses the ACE2 receptors to enter the human cells not the receptor for blood group. Whether some group develops severe disease depending on their blood group is another factor,” he says.

Several studies have attempted to establish a relationship between a patient’s blood group and susceptibility to infections and health conditions.

Blood type and stomach cancer

Stomach cancer, according to a 2019 study, was more predominant in people with blood type A or AB. To date 39 other studies have confirmed the Chinese population study. This was related to the finding that those with blood type A were also susceptible to H. Pylori, a causative agent of the cancer.

Of note is that stomach cancer is more common among men than women above age 55.

Reduce your chances: Reduce the amount of salt in your diet and keep minimal intake of foods preserved by drying, smoking and salting.

Blood type and fertility

Women with blood type O are more likely to experience infertility problems compared to other blood types. The study published in the Human Reproduction Journal showed a link between the blood type and high levels of the follicle stimulating hormone. The high levels of FSH hormones indicate a low production of eggs causing low fertility. The eggs produced may also be of lower quality.

The researchers noted that those with A blood group gene; A and AB were not likely to have this problem.

 Blood type and age-linked mental issues

A Neurology report study showed a link between blood type AB and a cognitive decline with advancing age. In fact, it showed that the risk of dementia and memory loss was 82 per cent higher than other blood types. The explanation given was that the AB blood type has larger amounts of a clotting protein (FACTOR VIII) that is linked with memory problems.

 Blood type and heart disease

A 2012 study published in the journal of Arteriosclerosis Thrombosis, and Vascular Biology showed that people with blood group O a lower risk of coronary heart disease compared to other blood types. The AB group had the highest risk at 23 per cent.  The study results didn’t change even when the researchers accounted for known dietary and risk factors.

Reduce risk: Eat a healthy diet, maintain healthy weight, give up smoking and reduce alcohol intake.

Blood type and blood clots

A study on 66,000 people over a period of 30 years, revealed that blood types A, B or AB had a much greater risk of developing blood clots with a potential of being life threatening compared to blood type O. The Dannish study showed that those with blood type O less susceptible to developing clots by 40 per cent.  

Reduce risk factor: Maintain an active lifestyle and reduce the durations you sit still. Also lose weight if overweight and eat a healthy diet.

 Explaining blood groups

Blood groups were discovered in 1900 by an Austrian physician named Karl Landsteiner. He went on to win the Nobel Prize in Physiology or Medicine for his research in 1930.

There are four blood groups A, B, AB, and O. These blood groups refer to the presence of different antigens on the red blood cell. If you have blood group A it means that you have antigen A, while blood group B means you have antigen B. Those who have AB blood type have both and B antigens on their red blood cells. If you have blood group O, you have neither A or B antigens.

There’s an additional antigen known as the D antigen. People who have this additional antigen are Rhesus D positive. Those who lack the D antigen are said to be RhD negative. The suffix (such as A+ or B-) in blood types usually indicates the presence or absence of the D antigen.