The splintering sound makes the habit seem far
worse than it is.
By Nicole Wetsman October
9, 2018
Scientists have conducted
fairly rigorous research into the long held belief that cracking your knuckles
will give you arthritis, and they've all come to largely the same
conclusion—it's probably not true.Deposit Photos
When he was a child, Donald
Unger’s mother and aunts warned that he shouldn’t crack his knuckles, because
he would develop arthritis. To prove them wrong, he set out on a half-century long
experiment, cracking the knuckles on his left hand at least twice a day, while
leaving the right knuckles (mostly) uncracked.
After 50 years, Unger (then
a doctor in Thousand Oaks, California) examined his hands—and found no evidence
of arthritis in either one, and no other differences between them, either.
He wrote
to the journal Arthritis & Rheumatology with his findings in 1998.
"This preliminary investigation suggests a lack of correlation between
knuckle cracking and the development of arthritis of the fingers," he
wrote.
This particular “study”
wasn’t exactly scientific—a sample of one isn’t nearly enough to reach a a
research-backed conclusion for the entire human population, and Unger wasn’t a
neutral observer. But since then, there’s been more rigorous research conducted
into the same question, and it’s to largely the same conclusion: Cracking your
knuckles probably won’t give you arthritis.
Kevin DeWeber, a sports and
family medicine physician at PeaceHealth Southwest Medical Center in Vancouver,
Washington, ran one such study—largely because he, too, is a knuckle-cracker.
“I’ve been cracking my knuckles for my whole life. Once I developed a
scientific mind, and once I got a job that put me in a position where I could
do some research, I looked into it,” he says.
The study,
published in the Journal of the American Board of Family Medicine in
2010, looked at x-rays of the right hands of over 200 people. About 20 percent
of those people reported that they cracked their knuckles routinely, but they
were not any more likely to have arthritis in their hands than the people who
did not crack their knuckles.
Despite the results of that
study and a handful of others, all reaching the same conclusion, the myth that
knuckle-cracking will lead to arthritis persists. Why? DeWeber thinks the
fracturing sound might have something to do with it. “Knuckle cracking is
really annoying to the people who are not doing it,” DeWeber says. “The people
who are annoyed want it to stop, so they come up with a story that will
dissuade the knuckle-cracker.”
That fictitious story isn't
entirely unreasonable, DeWeber says, even though it's probably wrong. Joints
crack because tiny bubbles of air form in the fluid that surround them, and
then rapidly collapse, producing the distinctive sound. Bubbles form and pop in
a similar way in ship's propellers, and in that environment they do cause
damage, so it's possible to make the argument that they'd harm joints, as well.
"But the mechanics of a ship's propellor and the mechanics of a knuckle
are different," DeWeber says.
Trauma to a joint can be a
risk factor for arthritis, and the loud sound of a knuckle cracking might sound
to some people like it’s a traumatic event. “You’re doing something forceful,
so it seems like it’s hurting the joint,” DeWeber says. “It’s a natural
conclusion people might come to, but it doesn’t have any supporting evidence.”
DeWeber is careful to note,
though, that there isn’t a 100 percent conclusive answer to the
knuckle-cracking arthritis query. It’s pretty likely that it doesn’t, and there
isn’t a scientific reason that could explain a connection between the two. But
to find out for sure, scientists would have to assign people to be
knuckle-crackers or non-knuckle crackers, make sure they stuck to their instructions,
and follow them for most of their lives, to see if arthritis develops. That’d
be incredibly difficult, DeWeber says, so the research we have now is likely
the best we’re going to get.
Unger won a 2009 Ig Nobel prize, which honors silly (but still
significant) science, for his query into his own knuckle-cracking habits.
During his own de-bunking of a well-meaning parental warning, he also
questioned some other decrees he was given as a child—like that eating spinach
was important. Unfortunately for Unger, though, that one isn't
a myth.
https://www.popsci.com/knuckle-cracking-health-myths/?utm_source=internal&utm_medium=email
No comments:
Post a Comment