Looking at weather and back pain

Posted on October 21, 2015

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I’m a little late to this, but last year the following study was published,

Effect of Weather on Back Pain: Results From a Case-Crossover Study

I was at a lower back pain conference recently, and actually ended up sitting next to one of the authors of this study, Chris Maher.

Chris wrote a summary of the study on the BodyInMind site here. The article was titled and started out as follows,

Weather back pain BodyInMind

I also saw this study on someone’s tweet. Something like “weather / back pain no correlation.” Now let’s go into a little more detail than possible with a tweet.

I talked with Chris about some of the points I’m going to go over below. For some of them, he was well aware (and the paper references some as well), and is in the midst of doing further research to get at those points. With the internet, and text communication in general, sometimes any criticism comes off as “BEGONE SATAN!” Chris seemed like a really nice guy, was generous with his time, and receptive to my thoughts. I had a lot of this post already written before talking with him, and tried to tone down my criticism even more since talking to him. Again, I don’t want this to come across as so much internet criticism comes across, where everyone is calling everybody idiots.

Furthermore, not all the criticism is aimed at the one paper.

We all already know weather *does* influence pain

Anytime someone goes “weather does not influence pain” I’m tempted to go, “Alright, how about you and I go outside in Minnesota, in December. I’ll have as many clothes on as I want, and you’ll have none. I’m sure nothing on you will be painful from doing this.”

It’s not like when we get too cold body parts don’t freeze over and literally die, right? I’m sure that’s not painful at all. The thing that (hopefully) prevents us from getting frost bite is a pain response. “My hands / feet / ears are killing me!”

I realize I’m speaking a general case of pain here. Not if a person has an increase in back pain. Context matters.

This *has* been rigorously studied

I wrote about weather and bodily sensations last year. I referenced a review, this one, which looked at weather pains. It made it clear most of the research is not as solid as desired, but one study, from a whopping 50 years ago, was incredibly well controlled. It was actually climate controlled.

This is still, to my knowledge, the most rigorous study on this topic. It of course has its own issues, a small sample size being the main one, but I’m not sure any modern study comes close to this one. This old study wasn’t referenced in the current study. I don’t believe anyone in the group was aware of it.

I doubt anything we look at moving forward will be able to be this rigorous. Some dismiss the older literature, but some also relish it. This climate controlled study was done for two weeks! Good luck getting that approval nowadays. “We cannot approve this study due to the psychologically ethically challenged nature of it.”

What did that 50 year old study did find? It wasn’t one meteorological variable, but it was a mixture of factors. Higher humidity and lower pressure. The present study looked at each individual variable in isolation. 50 years ago this was found to not have an affect on back pain.

-> “You’d be surprised how often they reinvent the wheel.”

This is a quote from a client of mine, who is a surgeon pushing 70 years old. I’ve begun to notice this as well. And that sometimes, when you try to reinvent the wheel, you end up with a not as good wheel.

Titling can get you page views, but be careful how you title

That blog post title of “Weather does not affect back pain.” Well, further down in that blog post,

“However, higher wind speed and wind gusts did slightly increase the chances of lower back pain,”

The point I want to make here, as this is often the case with health writing, is the title of this article does not jive so well with the actual results of the study.

I have a website, write about the health world, this is not as easy of an issue to overcome as it may appear. You can only be so accurate in a title, if nothing else because you only get so many characters. At the same time, you want to garner some viewership, and a longer -typically more accurate- title tends to turn people off. I know I have some posts where others feel I’ve made too sweeping a statement. Of course, those posts are some of the most viewed ones. It can sometimes be a tough balance to strike. People love broad stroke titles, but very little in the human body can be covered with one brush stroke.

The author does mention the increase in wind is not “clinically significant,” but I’m not really sure how they’re making that inference. In their study, some of the wind numbers have about a 15% higher odds ratio than all the other variables.

Regardless, “Weather does not affect back pain” followed by “wind slightly influences back pain” are not synonymous statements. The title is flawed, but I’m sure the twittersphere enjoys the first title more than,

With the exception of wind, weather not found to influence back pain

Or you could say,

Weather unlikely to be a factor with back pain

Or just do this,

Weather does not affect back pain?

We’re still lacking context though.

From the methods section,

“Consecutive patients presenting to primary care clinicians (general medical practitioners, physiotherapists, chiropractors, and pharmacists) for treatment of an episode of sudden-onset, acute LBP were recruited in Sydney, Australia,”

I’ve worked with a decent amount of people at this point. I’ve heard the “weather pains” from many, many people.

But I’ve never had someone who, because of the weather, felt the need to go into a primary care physician, or physical therapist, and get treatment. This study only included people who were seen within a week of the pain episode. The weather pains I’ve seen are more like a day or two of being more aware of something, maybe moving a little more gingerly on something, “I’m feeling a little out of it today, back is a little achey,” and then it’s done. Calling the doctor doesn’t happen. Calling the doctor, and after a few days your pain is severe enough you still feel the need to see a physician, I’m not sure you can classify that as weather pains. That’s likely pretty debilitating pain, and weather pain is not debilitating.

I don’t think anyone really contends a drop in air pressure, or a change in humidity, is going to influence back pain to such a degree a person feels the need to suddenly go into a doctor. It’s more like the person feels an extra aching that day, or a little out of it compared to normal. So they pop an Advil, or take it easy that day, and move on with their life.

This aspect in itself is enough to, in some ways, disregard this study. The authors try to position their research as going after an old wives tale, but this isn’t the right tale.

-With the exception of wind, weather not found to influence acute back pain episodes severe enough to warrant physician intervention

Back to that 50 year old climate controlled study- that study actually looked at people who already have osteoarthritis and rheumatoid arthritis. Meaning not only was it better controlled climate wise, it’s looking at populations we most care about!

Furthermore, those with an inflammatory or serious spinal pathology were excluded from this study. This is again, the population I’d most suspect to see some relationship (for some people) with weather pains. Those with arthritis, those with a surgical history, those with some hardware in their body.

With the exception of wind, weather not found to influence acute back pain episodes severe enough to warrant physician intervention in a population not expected to suffer weather pains

It’s perfectly ok to do a study on a healthy population and see how the weather influences their back pain, but this needs to be screamed in any discussion of the study.

The weather in our title is a little vague too. The most common response to weather pains seems to be when a storm is coming in, or when it’s raining. This coincides with our 50 year old study too. When rain is coming in, you often get a drop in pressure and an increase in humidity.

How much rain did we get in this study?

“During the study period of 13 months, the mean weather parameters were 1.4 mm of precipitation”

I did a quadruple take when I read this sentence, because I felt I had to be reading that wrong. Or forgot what a millimeter was. 1.4 millimeters of rain over an entire year. The type of weather we are most interested in with weather pains occurred often enough to give only 1.4 mm of precipitation. I live in San Diego, California, in the middle of some historically awful drought; only 1.4 mm still blows my mind.

-With the exception of wind, weather including barely measurable precipitation not found to influence acute back pain episodes severe enough to warrant physician intervention in a population not expected to suffer weather pains

I’m sure we’ve really lessened our retweet count by now. Let’s see if we can make it zero.

How a group does doesn’t always say how you do

I’ve gone over this some here and here, using the following graphs. In the first one below, all we’re illustrating is after being in space for a while, on a balance measure, most astronauts did worse, some had no difference, but one did better (the light blue circle).

Equilibrium score astronauts after space shuttle 30 minute line and more

In the next chart below, we’re illustrating the huge variability in eating response to exercise.

Exercise eating individuals

The above graph is crucial. While the group is found to have no influence on their eating from exercise -it averages out- you sure can’t say that about these two people,

Exercise eating individuals with outliers

In my experience training the “weather pains,” it’s few who have something like this where it’s regularly noticeable. As a population, I’d expect very little, if any, correlation between pain onset and the weather. For some people though? I’d expect some relationship.

-> Even then, I’m not sure I’d expect to see someone where every time the weather was a certain way, they had pain. Pain doesn’t work this way. It’s a mixture of many conditions needed. Maybe the weather happens to have the mixture of pain one day, but maybe you happen to be laying on the couch all day, relaxing on a Saturday, in your air conditioned home. Might not expect to see a pain response then. (Another reason the climate controlled study is superior. You largely get rid of these scenarios.)

People keep looking to find “100% of people had pain in response to X,” but that will never happen. Throw a spear through someone’s head and some will have pain, and some won’t. That doesn’t mean you disregard the spear element though. Or the likely fact “many people had pain from a spear to the head.”

-> At the conference I went to, in Chris’ presentation, he had a nice discussion on how he thinks the physical therapy world can be too hard on itself regarding it’s effectiveness. Are they as good as they or we want? No. Are they better -is certain exercise better- than most (many cases all) other treatments? Yes. Nothing is 100% effective. But we should take some solace in doing what’s most effective.

As far as I can tell, this back pain study only looked at things from the group level. A graph like the above isn’t found in the study. There are nearly 1000 people in this study. Just look at that chart above of 23 people, in a well controlled study. Do we really think one thousand dots are all going to line up in a straight line after looking at that graph? Or is it probably going to be all over the place? Is there any variable where humans all line up in one straight line?

Back pain weather graph

The highlighted is the primary measure the authors were looking at.

The odds ratio is where the authors made their conclusions. Notice the OR, third from the right, around 0.9-1.00 for most of the above. In one case for wind, the OR was 1.17. That’s where things started to matter statistically, although irrelevant in the authors minds. (The more you get above 1, the greater the association.)

The OR was calculated using weather within one standard deviation of the mean. For one standard deviation, 68% of the population lies between the mean.

Standard deviation normal distribution graph

Meaning this study looked at this aspect of the weather,
Standard deviation normal distribution graph 68% darkened

But we may very well be more interested in this area,

Standard deviation normal distribution graph 2-3sd darkened

The more extreme weather. For instance, the temperature values looked at were about 17 degrees with a standard deviation of 5. That translates to looking at things from 54 degrees Fahrenheit to 73 degrees. Maybe we need to look at a wider range to find something? Not only do we have a mild climate that we’ve looked at here, but we’ve only looked at the values closest to that mild climate.

-> An analogy: Look at an eating disorder. If you look at how everyone eats, then narrow that down and look at how the 68% closest to the average eat, you’re not going to find much.

But look at things wider than that, you may have to go out to 3 standard deviations to find something like anorexia (~0.6% of population), and suddenly you find something going on.

-> Illustrating how hard research can be: How many people do you need to study to make sure you’re getting some who have anorexia? It’s only 0.6% of the population. There are 318 million people in America. 318 million * 0.006 = 1.9 million. You could conceivably study 316 million people and still miss all the anorexics.

Beliefs don’t always have to clash with science

With this type of stuff, I get the impression some learn about the research (mainly the abstract) and then something like this happens,

Client / patient “I have trouble when it’s colder out. Or when a storm is coming in. I’m particularly achey those days. It’s harder to get around.”

Healthcare practitioner “Weather does not influence pain. It must be something else.”

Client / patient “Um, ok. But I think it matters for me.”

Healthcare practitioner “Ok. [moves on…frustrated…”ugh, idiot.”]

I’ve seen this exact type of communication with some pain science zealots. The pain science world is huge on communication and education. Body In Mind, where the original article was published, being the leader here. The author of the blog post commented how surprised they were at how much reaction they got, including some of the vitriol they received for their paper.

Chris mentioned this to me in person as well. I said, “Haha, well of course! I don’t know about Australia, but in the States, who knows how you get treated when you tell someone their beliefs are wrong!”

Scientists can be great with this. “Oh, the data has come out differently? I guess I’ll change my beliefs.” No problem. I’ve heard academics themselves state “we don’t always live in the real world.” This is where I think those who research full-time, or those with a good science background, may have some disconnect. The general population does not change their beliefs so quickly or easily. Look how long it took us to decrease smoking. (Look at what’s currently going on with climate change.)

I genuinely think the pain science crowd -more the pain science followers than those doing the research; the ones screaming at everyone on the internet “NOCICEPTION DOES NOT EQUAL PAIN!”- has a problem here. There is a troubling irony when the thing you extoll, education and communication, is the same thing you’re struggling with.

Increasing our irony, this community cannot stop hitting everyone in the face with a shovel reading “things like your beliefs influence your pain.” The study I’ve gone over is trying to disprove a belief people have about their pain! Yet we’re telling people “your belief doesn’t matter”? Are we sure the research is that solid?

We have to recognize we may not be able to disprove a belief. It’s very, very hard, if not impossible, to falsify certain beliefs. (See: God and when a person responds with “This is how I feel. You can’t tell me how to feel.”) If it’s not falsifiable, it’s not science. You may have research, you may have data, you may have opinion, you may have common sense, you may have logic, all aimed at attempting disproval of a belief, but you may very well not have science.

With pain, I’ve always been partial to the view, if you believe it’s bothering you, then it is. Working from there instead,

Client / patient “I have trouble when it’s colder out.”

Healthcare practitioner “Have you tried anything to help that?”

Client / patient “I’m not sure what I could do?”

Healthcare practitioner “Well, it’s your knee right? You could do something like when it’s colder out, putting an ACE bandage on the leg to keep it warmer. Or just wearing more clothing in general. You could also increase the heat in your home, and try to get moving more. It seems counterintuitive -you’re not feeling as well so you want to move less- but moving more helps get some blood flowing, which can help warm you up.

When it’s colder out, there can sometimes be a drop in air pressure. When the pressure drops, we think the body may expand a little bit, and this could cause some discomfort. This is like how people’s feet swell when on an airplane. By wrapping the joint we can not only keep things a little warmer, but decrease this expansion.”

(Discuss this more here.)

Client / patient “That sounds great. I’ll try those things. Thanks!”

Healthcare practitioner “Sure. In the meantime though, I want to make sure we are doing other things as well. Let’s talk about x, y z…”

None of that advice was potentially harmful. None of it was costly- an ACE bandage is a few bucks. And we may have gotten the person to exercise a little more in the meantime. All rather than trying to go on some diatribe about weather and pain research, where for some, arguing with their views on pain, health, eating, exercise, can often run the risk of getting into a religious debate.

You can work on changing someone’s beliefs, or showing them something they think is affecting them isn’t, but starting out by going “You’re wrong” is not the way to do it. Starting out by working with someone’s beliefs is a hell of a lot easier than immediately trying to challenge someone’s beliefs.

Woman client “I’m afraid of getting bulky.”

Male trainer “That doesn’t happen. Women don’t need to worry about that.”

Woman client [nervous] “Um…ok.”

Or,

Woman client “I’m afraid of getting bulky.”

Male trainer “Oh no problem. I understand. That’s a common concern. As we progress each month, make sure you let me know if you ever feel like you’re getting too big. We can always change what we’re doing, lift less weight, or do different exercises, to adjust things right away to stop that.”

Woman client “That sounds great, thanks.”

[few months go by and woman client has never mentioned getting bulky again]

What’s that phrase? Show me, don’t tell me? It works.

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Posted in: Lower Back Pain, Pain