Publicizing the Benefits of Donating Blood Could Relieve the Blood Shortage
The American Red Cross declared a blood crisis in January 2022 because of decreased donations caused by the CoVid-19 pandemic. This blood shortage required postponing elective surgery at some hospitals. A solution to this crisis could be increasing donations by publicizing the health benefits of donating blood, especially improved cardiovascular health.
Information touting the cardiovascular benefits of donating blood is already available on the web. A video on YouTube titled “Thick Blood Claims Lives: Blood Viscosity & Heart Disease Deep Dive” (https://www.youtube.com/watch?v=gabXVh9Ig5U&t=300s) has had over 124,000 views. The comments to the video show that people are aware of, and motivated by, this knowledge. The Florida Department of Health also promotes blood donation to improve cardiovascular health (https://www.floridahealth.gov/newsroom/2018/06/061118-4-benefits-donating-blood-getty-696120246-Article.html). According to the website, “Donating blood is a win-win for everyone involved. Receivers get a vital substance and donors get to burn calories, lower their risk of cancer and keep their heart healthy.”
Donating blood protects against heart disease by lowering its viscosity, i.e. thinning the blood (not to be confused with taking a drug that prevents blood from clotting, drugs commonly called “blood thinners). Like any other fluid, blood flows more easily when it is thinner. In one study, the viscosity of plasma (the liquid part of blood, as opposed to the red blood cells) was 22% lower one week after donating. New red blood cells are more pliable than the older ones they replace, causing a prolonged decrease in blood viscosity.
High blood viscosity is a strong risk factor for heart disease as shown by the Edinburgh Artery Study. This was a prospective study of 1,592 random men and women aged 55 to 74 years followed for 5 years. The difference in blood viscosity between people with and without heart disease was much smaller than the viscosity reduction achievable by donating. In other words, donating blood reduces blood viscosity long enough to protect until it is time to donate again, eight weeks.
The strongest evidence for the protective effect of donating blood comes from the Kuopio (Finland) Ischaemic Heart Disease Risk Factor Study. Kuopio is a region with a very high incidence of heart disease. In that study, 2,862 men aged 42 to 60 were studied for an average of almost 9 years. One man (0.7%) out of 153 men who donated blood had a heart attack compared to 16 (12.5%) of 2,529 non-donors. In a statistical model adjusting for age all other risk factors for heart disease, blood donors had an 88% lower risk of suffering a heart attack.
Unfortunately, not everyone is eligible to donate blood. These folks can receive therapeutic phlebotomy, which differs from blood donation only in purpose. In a prospective randomized trial of subjects with metabolic syndrome, two rounds of therapeutic phlebotomy decreased blood sugar by 12 mg/dL compared to 2 mg/dL in controls. Blood pressure decreased by 18 mm of mercury in subjects and only 0.2 mm in controls. The amount of blood removed in the study was similar to the amount removed at donation. Thinner blood flows more easily through muscle, allowing muscle cells to remove sugar from the bloodstream and store it where it belongs. Thinner blood flow needs less pressure to make it flow.
Received wisdom suggests that the safest blood products are from altruistic donors because incentives could motivate people to hide risk factors that might make their blood less safe. However, laboratory testing and post-transfusion surveillance for blood-borne illnesses are so effective that In April 2020 the United States Food and Drug Administration (FDA) shortened the deferral for men who have sex with men from 12 months of abstinence to 3 months. Given this capability, it is difficult to imagine how donations from people motivated to improve their health could pose a greater-than-average risk of transmitting a blood-borne illness.
Only one possible donation-associated death was reported to the FDA in 2015, the most recent data available on the web. In 2019, there were 805,000 heart attacks and 360,900 deaths due to coronary heart disease in the United States. The benefit-to-risk ratio of blood donation to prevent heart disease is potentially very high. There is no question that recipients of blood donation benefit, and increasing evidence shows that donors benefit as well. The real question physicians should ask is, “Is it ethical not to promote the health benefits of donating blood?”
