Tuesday, December 8, 2015

Too Short for My Own Arms

I made a disconcerting discovery today.  A friend had bought some twine to use as a laundry line for an upcoming trip to Afghanistan (yes, Afghanistan...I have adventurous friends), and cut extra lengths for future trips (she travels a lot, but always has really clean clothes). She was measuring the lengths using her open arms, and I was curious how she knew exactly how much that measured, and how, when I asked that question she knew the exact answer. I tested her guesswork and found she was exactly right, to the centimetre!  My friend looked at me like I was crazy.

"Didn't you know that the breadth of your arms equals your height?"

I must have been away from school that day.  I totally did not know that.

We went around the room and tested it with her husband, with my husband, the cat.  Everyone, except me!

I seem to be freakishly short for my own arms. Well, not freakish, that is a wee bit of an exaggeration. But there was a considerable difference. Inches, even.  The question then popped up: Is it my height that is too short or my arms that are too long?

Standing back-to-back with my sister last summer, I do remember being quite shocked at how much I had apparently shrunk over the last few years, as we used to be the same height. And the only thing that has changed in those years is the advancement of my scoliosis. So, it seemed clear to me that it is a height thing and not an arms thing.

And that's a bit of a shock, that the change in my back is translating into such a fundamental characteristic of someone's person as their height.

My friends brought out a book and showed me a diagram I have seen many times but never really connected to on a personal level: Leonardo da Vinci's  "Vitruvian Man".
aka The Guy in The Circle

Therefore, the assumption is that my height loss could be estimated as my armspan minus my actual height.

I did a bit of research on a variety of studies (legitimate, peer-reviewed studies only!) that used 1 or more of 4 radiographic methods: Bjure, Kono, Stokes and Ylikoski (which sounds like the start of a joke: Four guys walk into a bar - a Swede, a Polynesian, an American and a Fin....) to see if it was possible to correctly calculate height loss due to scoliosis.  The studies I looked at included a various range 30 - 250 people with a variety of scoliosis types (lumbar, thoracic, cervical, etc.).

In general, the studies assumed that spinal height loss occurs only as a result of altered curvature, without alteration in disc height associated with an increase in scoliosis. Calculations based on the Cobb angle (which is two dimensional) produced inaccuracy, with suggestions that data considering trunk size could be added.  A longitudinal study was suggested as perhaps having advantages over these cross sectional studies, since any loss of discs' height occurring in progressive scoliosis could be taken into consideration.
In the end, all studies I looked at determined that there was no overall agreement between the four methods of calculation of the loss of body height associated with scoliosis.
However, my online quest on the topic also turned up a lot of discussion forums debating this issue, and agreeing that the generalization (that is the Vitruvian Man) only works as a rough estimate, and there are a lot of people who have naturally longer or shorter armspans by up to several inches. 
And of course everyone loses some height as they age. That's gravity for you. Always rushing up to greet you and ruining the party. Thanks a lot Isaac Newton (even though you have got awesome hair!)
aka The Guy With The Apple Landing on His Head
Another study (French) measured over 8,000 women over 60 and found they all overestimated their height by an inch, on average, and had lost about 2 inches from their tallest recalled height, just as a matter of age. The average person was estimated to lose ¼ to ½ inch every decade after age 40 or so, with women generally losing more than men (all those years lugging groceries home and carrying kids, grumble, grumble). People lose height because the discs between the vertebrae in the spine dehydrate and compress. The aging spine can also become more curved, and vertebrae can collapse  due to a loss of bone density, not just due to scoliosis. Losing muscle in the torso can also mean stooped posture. Even gradual flattening of the arches in the feet can make you slightly shorter.
As well, the greater the shrinkage, the greater the risk of hip and other fractures. Several studies were cited as having found that those over age 65 who lost at least 2 inches in the past 15 to 20 years were at signifi­cantly higher risk for hip fracture than those who shrank less.
Of course, that is largely out of anyone's control, as it's down to genetics, lifestyle, age living on this planet and how much bone you built when you were young.  Suggestions to help counteract the negative aspect of height loss include weight-bearing exercises, taking calcium and vitamin D, not smoking or binge drinking.  One (Belgian) study actually found that those who did moderate aerobic exercise throughout their lives shrank less than those who lived more sedentary lives.
So the reality for me is pretty clear - I have lost some height due to scoliosis and some height due to age.  But it also means my laundry line will be just that little longer!

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