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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Does vitamin D prevent formation of blood clots?

A venous thrombosis is a blood clot that forms within a vein. A classical venous thrombosis is in a deep vein thrombosis, usually deep in a vein in the leg. These can break off, go to the lungs, and become a life-threatening pulmonary embolism. Complications of pulmonary embolism include coughing up blood, heart failure or shock, heart palpitations, pulmonary hypertension, severe breathing difficulty, severe bleeding (usually a complication of blood thinner treatment), and sudden death.

Venous thromboembolism is a major health problem. The average annual incidence of venous embolism among Whites is about 700,000 cases per year. The incidence appears to be higher among Blacks. Pulmonary embolism is predominantly a disease of older age as rates go up steeply with age. The incidence rates are also somewhat higher in women during their childbearing years. Birth control pills are a major risk factor for blood clots. An Italian study showed pulmonary embolism peaked in December.

Does vitamin D play a role in venous thrombosis? Dr. P. Brøndum-Jacobsen and colleagues of the Copenhagen University Hospital in Denmark obtained vitamin D levels on more than 18,000 patients and then followed them for up to 30 years to find out.

Brøndum-Jacobsen P, Benn M, Tybjaerg-Hansen A, Nordestgaard BG. 25-hydroxyvitamin D concentrations and risk of venous thromboembolism in the general population with 18,791 participants. J Thromb Haemost. 2012 Dec 29.

The mean follow up time was 13 years for this cohort, which averaged 57 years of age. Nine hundred and fifty patients ended up with a blood clot; the average time to a blood clot was 13 years. When the authors split baseline vitamin D levels into tertiles (one-thirds), they found those with the lowest vitamin D levels were 37% more likely to have a blood clot. After statistical adjustment, the relative risk increased to 106% for those with the lowest levels.

The authors postulated three mechanisms by which higher vitamin D levels were protective. First, vitamin D deficiency may lead to a decrease in the gene expression of anti-blood clot proteins (antithrombin in the liver and of thrombomodulin in the aorta) leading to more blood clots.

Second, vitamin D deficiency may lead to an increase in the gene expression of a protein (tissue factor) in the liver and kidneys, which will lead to more blood clots.

Finally, in human aortic smooth muscle cells, vitamin D like drugs have been shown to reduce the production of certain blood clotting factors (plasminogen activator inhibitor-1, thrombospondin-1, and thrombomodulin) leading to an overall anti-thrombotic effect. It turns out that atherosclerotic cardiovascular disease and blood clots may not be as separate a disease, as the two diseases share some common risk factors. It may be that reduced plasma vitamin D could be an independent and common risk factor for both conditions.

The authors concluded,

“The consistent and stepwise increasing risk that we found may tempt to suggest causality; however, one cannot infer causality from the present study. Therefore, randomized intervention trials are needed to test the question of causality, and randomized trials with vitamin D supplementation are needed before implementing supplementation in the general population or in selected patient groups to reduce the risk of venous thromboembolism.”

I disagree in that the time to act is now. Treatment of vitamin D deficiency cannot wait for further science. While scientists are required to wait, physicians caring for patients are ethically required to act on what is known now; they cannot patiently wait to find out what may be discovered in the future. Physicians have always been required, both ethically and legally, to preform risk benefit assessments of treating or not treating vitamin D deficiency. We know there are potentially huge benefits and simply no significant risks of treating deficiency.

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

7 Responses to Does vitamin D prevent formation of blood clots?

  1. Rita and Misty says:

    Dr Cannell,

    Thank you for courageously being “the voice of reason” regarding treatment of Vitamin D deficiency. I truly appreciate your efforts.

    I hope you never tire of fighting the good fight….

    To Sunny Days,


  2. This article and links to several similar items are in VitaminDWiki


  3. jkwray1@cox.net says:

    Dr. Cannell, I just heard of a study on Fox News that said cancer deaths are down 20% since peak in 1991. Can you tell us how much higher vitamin D usage is up since 1991? They didn’t mention any correlation… Hmmmm!


    • Brant Cebulla says:


      Vitamin D levels have actually dropped a little since the early 90s I believe, mostly due to our ever-increasing shift from outdoor jobs to indoor jobs.

      As to why there’s been a 20% drop in deaths due to cancer, without knowing much on the subject, I would guess it’s because treatment of people with cancer is improving.

      Thanks for sharing the article,

  4. Rita and Misty says:

    Off topic from Dr. Cannell’s posted blog; but inline with the topic of cancer raised by jkwray1@cox.net:

    Vitamin D in combination cancer treatment: “In summary, calcitriol has shown potential in enhancing the antitumor activities of a variety of cytotoxic or differentiating agents. The combination treatment studies with calcitriol do provide evidence and support for the continued study of calcitriol in cancer chemotherapies.”


  5. jack says:

    Dr. Cannell, I agree with you totally. Ibelieve that enough has been learned about vitamin d deficiency, and it’s effect on all aspects of human health, there should be no delay in educating the general population about the need to test for vitamin d; and then to either supplement with D3, get back into the sun, or use a proper tanning lamp.

    There is an out-cry to lower health costs; but then some of the politicians are attempting to ban over-the -counter supplements such as vitamin D3. It’s time to get real!


  6. eewright says:

    Couldn’t agree more Dr. Cannell…there is not a moment to lose for all populations to get tested and get their Vit D levels up. I had severe Laryngopharyngeal Reflux and no medication or surgery worked to relieve me from severe excruciating pain of acid vapor burning through my throat nerves. In fact I got 10x worse on medications and surgery. I then developed incontinence and severe pain of the shoulders and joints. My Drs cut me lose and told me there was nothing more they could do for me. In desperation I went on the internet to do reserach. I knew my UES spinchter wasn’t closing off the sphincter in my upper esophogus through my own self study. No Dr explained anything to me. Up popped on the internet a few articles on Vitamin D and muscles strength. The rest is history for me. I have slowly gotten better the higher my D levels go. I was saved by this simple, inexpensive hormone, from a horrible deblitating slow death from LPR. The incontinence disappeared and the shoulder joint pain went away. I’m a firm believer that what is missing from a Dr’s medicine bag is knowledge of the critical importance of Vitamin D in all aspects of health at the right levels. On a side note, I avoided the sun for 40 years. In the early ’70 we were all scared to death by the media on the dangers of the sun. What a big mistake I made avoiding the sun for 4 decades. I can only hope that I recover fully with time. And as one more example of my putting my own expermentation into “practice” with my family, my husband’s mother, who is 87, went into ER last Fall 2011 and was so weak and unable to eat. The Dr asked her in front of her grown sons why she even bothered to come into the ER, that she is dying and should just go home and die. My husband and his brothers where stunned. I told my husband to get his mother off as many medications as was possible and to put her on Vitamin D. She has slowly recovered and walks with no walker now and is no where “dying”. Her once balding head is full of hair and she looks 20 years younger. My whole family thinks I should be a Dr. I try to explain that its a simple but necessary hormone that none of us are getting enough of. It is a truely a unbelievable state of medicine to have something that would help illness off all types and it is not yet part of mainstream medicine. There must be alot of money being made of sick populations for the medical community not to pay attention to the biological need of hormone D at the right levels, based on weight, latitude, skin color and age. It is a crying shame because I kow how much I suffered with pain and desperation for relief and I know other patients world wide will succumb to illness for lack of enough D for no good reason. The science is here but the medical community looks at you blank when you tell them it was D that got you better.