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Posts Tagged ‘arthritis’

XC skiing and arthritis

April 18th, 2011

To be perfectly honest, I wasn’t thrilled to see the results of this study (tweeted by Amby Burfoot). But data is data*, and if you report the good news you can’t ignore the bad. Swedish researchers did a very cool analysis of 54,000 men and women who competed in the famous 90 km Vasaloppet classic-style nordic ski race between 1989 and 1998 (full text available here). What’s fascinating is that Sweden keeps meticulous records of all its citizens, including all the in-patient health care they receive, linked to a 10-digit identification number. So the researchers were able to link the names and finishing times of all the racers with their health records, census data (to check confounders like education, occupation and income), death records and emigration records.

The basic question they looked at was: does exercise (as represented by the number of times subjects raced the Vasaloppet in the 10-year window, and their fastest finish) correlate with severe osteoarthritis later in life (as indicated with having a knee or hip replacement due to arthritis). The answer, unfortunately, was yes. For example, those who completed five or more races and had a fast finish time were 2.73 times more likely to need a joint replacement in the following ~10 years than those who participated only once and had a slow finish time.

The results contrast with a string of recent studies that found that, if anything, longtime runners are less likely to develop arthritis than non-runners. So there are a few questions here. Does the skiing motion have some unique effects on joints, causing more stress and cartilage damage? Or is it more a question of degree: “moderate” exercise is good for the joints, but 90 km ski races (which took between four and 13 hours to finish) are a bit too extreme? I don’t know, but I suspect the latter is a factor.

One point worth noting. Compared to similar studies of the general population, the skiers as a group had exactly the same risk for knee replacement, and a slightly higher risk of hip replacement. That suggests that, while the elite athletes at the front of the pack were worse off than the general population, the “casual” exercisers toward the back of the pack were in fact better off than the general population (though “casual” isn’t really the right term for someone doing a 90 km ski race).

And a last point: the same group has made several other studies of the characteristics of Vasaloppet finishers. Even if their knees get creaky, they do live longer than their sedentary peers; and the more races they do, the longer they live. So that’s something, I guess!

[* I know, "data" is supposed to be plural. Hopefully people will overlook this transgression... :) ]

Running, arthritis and your knees: more studies

October 13th, 2010

There’s a nice article in today’s New York Times by Gretchen Reynolds, discussing recent research on knees, arthritis and vigorous exercise. In particular, there’s a new meta-analysis by Australian researchers that raises some interesting questions about the role of bone spurs — whether they might actually be a beneficial adaptation to the stress of exercise, rather than a sign of impending doom. (I blogged about this study here back in July.)

It’s definitely more complicated than “running ruins your knees” or, conversely, “running has no effect on your knees.” Physical activity has inevitable effects, and your body adapts to it — the question is whether this adaptation is good or bad. Worth a read.

The trouble with acupuncture studies

August 24th, 2010

Tara Parker-Pope has an interesting article in the New York Times about a recent study on acupuncture for pain relief, and more generally about the difficulties in testing acupuncture (and other forms of “traditional” or “integrative” medicine) using standard Western research methods.

The study tested acupuncture versus a sham treatment (that also involved needles, but inserted in the “wrong” places and not as deeply) in 455 patients suffering from knee arthritis. Both groups experienced relief — their pain decreased by one point on a scale of 1 to 7 compared to controls who received no treatment at all. This is consistent with a series of earlier studies suggesting that “inserting needles in or around an area of pain may have caused a ‘super placebo’ effect, touching off a series of reactions that changed the way the body experienced pain.”

The NYT article is worth reading for the discussion of what can and can’t be tested with traditional blinded clinical trials. And then there’s the even harder question: if the effects of acupuncture are essentially a placebo, but a powerful one, then what do we do? After all, the results — pain relief — are surely more important than the mechanism. But what if we establish once and for all that it’s a placebo. Does that mean its effectiveness will disappear? Is it better to remain ignorant so that treatments like acupuncture will work?

How exercise affects knees: bone spurs vs. cartilage

July 30th, 2010

Conventional wisdom tells us that running and other forms of vigorous exercise will ruin your knees. A number of studies, on the other hand, have found that long-term runners are actually less likely to develop osteoarthritis in their knees than non-runners, as I’ve written about before. So how we reconcile these conflicting beliefs?

Australian researchers have just performed a large-scale analysis of existing research in an attempt to answer this question, in a paper that was posted online by Medicine & Science in Sports & Exercise earlier this month. They started by scanning 1,362 relevant studies, and eventually winnowed that number down to 28 high-quality studies (which gives you some idea of the number of lower-quality studies out there!). Six of them were MRI studies, with the remaining using X-rays to assess cross-sectional and longitudinal links between exercise and knee joint status.

Here’s what they found:

i) strong evidence (from multiple high quality cohort studies) that there is a positive relationship between osteophytes and physical activity;

ii) strong evidence (from multiple high quality cohort studies) that there is no relationship between joint space narrowing, as a surrogate for cartilage thickness, and physical activity;

iii) limited evidence (from a cohort study and two cross-sectional studies) that there is a positive relationship between cartilage volume and physical activity;

iv) strong evidence (from multiple high quality cohort studies) that there is an inverse relationship between cartilage defects and physical activity.

In other words, exercise results in fewer cartilage defects, and may actually result in increased cartilage volume, but also results in more osteophytes (also known as bone spurs).

So what does this mean? Bone spurs aren’t generally a good thing, but decreased cartilage (as measured by joint space narrowing) is the most common way of monitoring the progression of degenerative conditions like arthritis. The researchers suggest that, in this case, the bone spurs may simply be a reaction to the forces of exercise, and don’t indicate that the joint is degenerating:

Thus, in response to mechanical stimuli, such as physical activity, osteophytes may enhance the functional properties of the joint by increasing joint surface area for the greater distribution of load or reducing motion at a joint and improve joint stability… While it is possible the higher prevalence of osteophytes identified in people exercising may be detrimental to the knee joint, it could also be argued, in the absence of cartilage destruction, that physical activity is beneficial and osteophytes are simply a response to mechanical stimuli.

To be perfectly honest, it sounds like they’re stretching a bit to make things sound good. “What, exercise causes bone spurs? Well, maybe bone spurs are actually good for us!” But for most people, loss of cartilage is a far more serious consideration, so overall these results are (once again) good news for people who exercise regularly and don’t want to have to replace their knees when they turn 60.

Staying healthy after 153,300 miles

April 12th, 2010

Runner’s World has an interesting interview by Amby Burfoot with marathoning legend Ron Hill, now most famous for the daily running streak he’s kept alive since 1964. A passage I liked:

I saw a woman who said, “Running’s not good for your knees.” I said: “Okay, but I’ve got 150,000 miles on these knees and they’re working quite well.” She said: “That’s only because you’re so slim.” I said: “Well, how do you think I got this slim, and stay this slim?”

He has a good point (as I discussed in a Jockology column a few years ago). On the other hand, I have to admit that the picture accompanying the interview does look like a guy who hasn’t taken a day off in the last 45 years.

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CRM: Ed Whitlock feature

October 11th, 2009

Anyone who follows masters running will have heard the name Ed Whitlock. He’s the man who ran a 2:54 marathon at age 73 back in 2004, the first septuagenarian sub-three. That famous marathon is just the tip of the iceberg when it comes the records he’s set at a ridiculous range of distances over many years, thanks to his famous training regimen of up to three hours of slow, steady running around a local cemetery every day. But all has been quiet on the Whitlock front for the past few years, thanks to knee problems.

That may be about to change, according to a fantastic in-depth feature about Whitlock in the upcoming issue of Canadian Running magazine, by Michal Kapral. Ed is on the comeback trail! Definitely worth a read… (Heck, it’s worth clicking on just to see the photo of Ed racing in 1952 at the Hyde Park Relays — an event I competed in nearly 50 years later!)

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Arthritis, exercise and obesity: some unexpected results

October 8th, 2009

A couple of recent studies worth noting, one surprising, the other not.

First, there’s a new Cochrane Systematic Review recommending exercise as a form of treatment for rheumatoid arthritis, to improve “functional ability.” It’s already fairly well-established that exercise is helpful for osteoarthritis, which is the more common (about 1 in 10 people will get it) and better known form of arthritis. But the evidence about exercise and rheumatoid arthritis, which is less common (about 1 in 100 people will get it), is a little thinner on the ground, so the Cochrane review is interesting.

“Based on the evidence in this study, we would recommend aerobic capacity training combined with muscle strength training as routine practice for RA patients,” said lead researcher Emalie Hurkmans of the Leiden University Medical Center in Leiden, Netherlands. “But we need more research to establish the recommended length and type of exercise programs, whether patients need to be supervised and if these programs are cost effective.”

All of this makes the second study a little more surprising. In a mouse study, Duke University researchers found that obesity, on its own, does not cause osteoarthritis. Because of the strong link between arthritis and obesity as a risk factor (one of the reasons exercise is so important), researchers have assumed that the extra weight puts strain on joints, which then leads to degeneration and ultimately arthritis.

But in the new study, researchers used mice that either didn’t have or couldn’t process the hormone leptin, which helps to regulate appetite. No matter how fat these mice got, they didn’t have an elevated rate of arthritis. Mice with normal leptin levels, on the other hand, developed significant knee arthritis when they got just half as fat as the leptin-free mice.

So what’s going on? It’s not clear, since leptin influences factors like body weight, inflammation, sex hormone levels and bone metabolism, all of which could affect the development of arthritis. What it implies is that loading your joints with extra weight isn’t what causes arthritis — the strong link between obesity and arthritis appears to be chemical instead.

“We knew from other studies that obese people got arthritis in their hands, too, which don’t bear weight. This indicated that something besides just body-weight level affected their joints,” [one of the researchers said].

Just to reiterate: the link between arthritis and obesity is as strong as ever. It’s just the mechanism that isn’t as simple as we thought.