Chiropractic Calgary AB waiting room

6 Scientific Studies That DEBUNK the Chiropractic Stroke Myth


Hi Practice Members of Calgary

I thought this was an appropriate time to discuss what SCIENCE actually says regarding chiropractic and strokes. As many of you may have seen this week,
the sensationalistic mainstream media is publishing misleading propaganda left and right in an attempt to fear monger.

Now I don’t want to be insensitive to Katie May’s unfortunate circumstance.

Let’s just be clear on the facts before we start making major claims.

I am not giving you my personal opinion here, I am informing you of what the SCIENCE states in regards to chiropractic adjustments and strokes.

My intention is to inform you of the facts and let you derive your decisions accordingly. This is likely the most important article I have written.

I know it’s long but I suggest you read it all.

I find that this discussion becomes more emotional and political than scientific.

Unfortunately, what we see on our TV’s or read online often doesn’t reflect what science actually reveals and I just caution everyone about making their healthcare
decisions based on information from mainstream media.

Sadly, most people and doctors don’t know how to read science. Even worse, many don’t know how to tell good science from bad!

Unfortunately, unless we have a research background, we just don’t learn that.

I personally would never claim to be a scientist.

That said, I have someone like that in my back pocket that I use to truly understand the science. He has an excellent write up on this topic too, reference 6 below.

Most people aren’t aware of the reporting practices of many pharmaceutical companies where most doctors get their information.

For example, when we look at cholesterol medications. Did you know that they are allowed to publish the relative risk reduction by using a statin medication?

What that means is, they can publish to the public or medical doctors, that statins create a relative reduction of heart attacks by 50%.

However, when you look at the studies, you see that without statin use the risk of a heart attack is actually 3/100.

But, in the study, they show that the risk is 2/100. With 3 being less than 2 by 1 that’s a 50% relative reduction but in terms of absolute reduction, it’s actually nominal.

(Now we know from more investigation and the manipulation of data, that statins actually have no effect on the risk of heart attacks…but that’s for another day.)

The studies below debunk nonsense claims and prove once and for all that chiropractic neck adjustments are safe.

I understand why patients might feel confused and conflicted by the stories flooding the news.

My view is to always look at things logically.

First off, the particular type of stroke being referenced is called a Vertebrobasilar artery dissection, abbreviated VBA or VAD. Which means a tear in the artery, which is incredibly rare.

Not to be confused with the much more common blockage or clot in the artery due to atherosclerosis.

According to study 4 from Dr. Walter Herzog out of my alma mater, University of Calgary. Neck adjustments (cervical manipulation) provides no more stress to the arteries in the neck then normal range of motion or simply turning your head!

Being a former international level wrestler, I personally have always known that the amount of force used in a my adjustments is WAY less then I would use while

Logically, lets all think about this…

For those of you who have had your neck adjusted and have been in a car accident. What would you say had more force on your neck? (Don’t worry, I know cause I’ve read the science.)

How many of you have watched your child get hit in hockey or football? Would you say there is more force to the neck there?

Now think of mma or boxing.

I personally have received all of the above and I can tell you that there is no comparison to the same amount of force with a chiropractic adjustment to the neck.

Logically…if that was the case, people would be stroking out all the time with regular daily activities or accidents.

Some researchers suggest that it’s is the accumulation of events, not just one event that leads to VBA.

Perhaps the significant fall that Katie May had two days before, which actually brought her to the chiropractor, for example.

But, that is not the case. A VBA is so rare, it’s actually hard to even study. Because it is so rare, we don’t have really great science in the first place. The studies required would need millions of patients, the costs would be extremely high and may not be humanly important to pursue.

Not to downplay anyone who has ever experienced a VBA.

Although we have limited data, the trend is quite clear in any study worth the paper it’s written on… There is no causal relationship between chiropractic and VBA.

According to study 1, the odds of this type of stroke in normal population, whether seeing a chiropractor or not is 1-1.5/100,000 and occurs in 1 in 5.85M people.
Just to put that in reference, the risk of getting struck by lightening in your lifetime is about 1/3000!!!

I don’t know about you, but I can’t remember the last time I worried about getting struck by lightening.

This stance becomes even more logical when considering the fact that common medical procedures (including over-the-counter non-steroidal anti-inflammatory drugs [NSAIDS] eg. Advil, Aspirin, Aleve, Motrin) for health problems stemming from the joints, nerves, and muscles of the neck have medically acceptable risk ratios far
exceeding even the highest risk estimates for chiropractic.

In fact, if you look at study 5. The best evidence indicates that cervical manipulation for neck pain is much safer than the use of NSAIDs, by as much as a factor of several hundred times.

Death rates from NSAIDS use is between 1/100-1/400 for similar conditions a chiropractor would treat!

This means you have thousands of times more risk of dying from taking an advil or aspirin for your neck pain than seeing a chiropractor. In fact, research shows 18,000 related deaths annually from NSAIDS in North America!!

That’s the 15th most common cause of death in the US alone.

Trust me, if Chiropractors had that track record, we’d be under a hell of a lot more scrutiny!

I understand though, that any preventable risk is a risk that should be avoided if possible.

I want you all to know, that I am personally not tied to a cervical adjustment. I receive the procedure, I perform the procedure everyday at the office and I even perform it on my loved ones.

I have performed well over 200,000 neck adjustments over the past 12 years.

That said, if the chiropractic adjustment had the risk of causing a stroke to my children, I would 100% not do it.

I am not tied to the procedure, if it is unsafe. However, the research doesn’t support that. In fact, as you’ve just read, the research demonstrates the exact opposite! Much safer than the alternatives!

If we look at study 2 below. They included all residents of Ontario over a period of 9 years (1993–2002) 109,020,875 person years of observation.

They identified 818 VBA’s resulting in hospitalization. (RARE)

They sought out to determine whether there was a statistically significant difference in patients experiencing this stroke in a Medical doctors office vs Chiropractors office.

Both study 2 and 3 below, determined that the likelihood was no more in a Chiropractors office, than an MD’s office. In fact, there was actually a slightly lower
incidence in the chiropractic office. (Some may see that as, chiropractic actually prevents this type of stroke.)

I’m not willing to say that but science can be read that way.

The real distinguisher here was… MD’s don’t perform ADJUSTMENTS!!

Yet, they still have patients experience these types of strokes after visiting them.

Meaning a VBA is rare unfortunate events that happens to some people, whether or not they see a chiropractor.

Their conclusion as to why there may be a slight increased relationship (not causal) between chiropractors or MD’s and VBA,


Neck pain and headaches. This is the most common symptom associated with VBA. It’s also a very common reason to see a chiropractor or MD.

What that means is, people are likely already having the stroke, which is why they are presenting to the Chiropractor or MD.

It’s simply a timing issue not a causal issue.

If I get in a car accident after I brush my teeth, did brushing my teeth cause the accident?
There are millions if not hundreds of millions of safe neck adjustments performed each year by chiropractors in North America.

I would imagine we would be seeing this much more frequently if there was a causal relationship.

The vast majority of cases of VBA (98%) in our population have NEVER received chiropractic cervical adjustment.

Unfortunately, it is a rare spontaneous event people can experience and is nothing more than a coincidence in relation to chiropractic.

Just so you know, the average chiropractor pays anywhere from 1/5 to 1/10 in malpractice than the average medical doctor.

If for one second insurance companies thought (or had hard data) to prove chiropractic adjustments were risky, malpractice premiums would skyrocket

My malpractice insurance is much less than my car insurance, almost half! I haven’t had a car accident since I was 16!

In a perfect world, the media would share the MILLIONS of testimonials, case studies, and miracle stories about how chiropractic has helped patients live healthier and regain their lives.

We know why they don’t put that on the front page, though.


I keep fighting the good fight and share this research with your friends and loved ones so they have the facts.

Have a great weekend,

Dr. DJ Ledrew