4th Thursday Update

May 28, 2015

I didn't like my fasting test, though I more or less expected it to be up this morning (late dinner last night, and too many carbs). Well, I made up for it with a low-carb lunch and got post-prandial result which was scarcely higher than the fasting test had been. Whenever I get a fasting result that's higher than I'm comfortable with, I spend the day taking extra measures to bring my glucose down. In this case, a low-carb lunch and a long trail-run after work.

Good glycemic control isn't about never seeing unwelcome changes in your results; it's about reacting to those changes when they occur.


Blood Pressure

Hypertension (abnormally high blood pressure) is a big issue for people with Type 2 diabetes. Such patients very often have hypertension, and are at risk for the cardiovascular problems and kidney problems associated with it. Diabetes is already a risk factor for such problems, all by itself; combining diabetes with hypertension magnifies the risk considerably. Anyone with diabetes is well advised to keep blood pressure under control.

Why is hypertension harmful? Apparently because exposing your arterial walls to chronically excessive pressure tends to have a traumatizing effect on those crucial tissues, causing them to become inflamed. Inflammation of the arterial walls causes various problems there, including a tendency for plaque to build up (and then break loose), and a tendency toward bleeding (and clot formation). All of that puts you at risk for every sort of cardiovascular ailment known to medicine. Type 2 diabetes is hard enough on your arteries by itself (apparently because of the impact of the high levels of insulin you must maintain to compensate for your loss of insulin sensitivity); you don't want to expose your arteries to the inflammatory effects of hypertension is well.

There are a lot of ways to control high blood pressure. The most effective method (regular exercise) is also the least popular -- so unpopular that it is seldom even mentioned in discussions of treatment for hypertension. I'm just throwing it in because I think someone ought to mention it, and I'm the only one likely to do so. I know it works for me. (Tonight my blood pressure is a remarkably low 101/70, owing to the trail-run I did after work. I've been off hypertension drugs for years; my blood pressure seems to stay under control so long as I keep working out.)

What doctors are interested in, however, is drugs, because they think their patients (especially their Type 2 diabetes patients with high cardiovascular risk factors) are certainly not going to take exercise but might very well take pills. So, which pills are the ones likeliest to help diabetes patients? Many different kinds of hypertension drugs are available.

Suetonia Palmer, at the University of Otago in New Zealand, has done a study of the "Comparative efficacy and safety of blood pressure-lowering agents in adults with diabetes and kidney disease". The results, when evaluated in terms of the always-important medical criterion I call "not dying", are as follows:

The greatest reduction of mortality was in patients who received a combination of two drugs: an ACE inhibitor (lisinopril, or one of the other "-pril" drugs) and a calcium-channel blocker (amlodipine, or one of the other "-dipine" drugs).

The least effective drugs (resulting in a significant increase in mortality) were the beta blockers (propanolol, and the other "-olol" drugs).

So there you have it: your best bet for not dying, if you have diabetes and high blood pressure, is to combine a "-pril" drug with a "-dipine" drug.

At least, that's your best bet if you're going to solve this problem with drugs. I don't know how the efficacy of the drugs stacks up against exercise. I downloaded a ten-page document describing the New Zealand study, and exercise wasn't mentioned in it.

So, as usual, the message is: your survival depends on pills!


Correlation strikes again!

One of the problems associated with health research is that it usually cannot involve anything like a controlled experiment. We don't raise people in cages, like lab rats, and control their environment and behavior so that we can isolate a single factor to see what its health impact is. Instead, we usually have to rely on observational studies which find that men who wear silk neckties seem to have less epilepsy, while women who hate seafood seem to have higher rates of depression. I made those examples up, but that's the kind of thing that happens when you look over a bunch of data and start finding that one trend correlates with another. In all likelihood, the correlation between Thing A and Thing B is either a coincidence or reflects a connection to some Thing C that you haven't thought of. If periodontal disease is a bit less common in people who play golf than in people who don't, the explanation is not likely to be that golfing protects your gums. (Having enough money to be able to play golf, however, might be a factor.)

For a real-world example of the problem I'm referring to, look at this headline I spotted today:

Come on, guys!

I don't care how well exposure to traffic noise correlates with increases in abdominal fat; you're never going to make me believe that the noise is what's causing the weight gain. People who live around traffic noise probably differ from people who don't live around traffic noise in a dozen identifiable ways. Start looking into those differences, and then come back and tell us what you found out!


3rd Thursday Update

May 21, 2015


Adventures in plain English

Randall Munroe, the nerd-hero cartoonist behind the XKCD comic, once did an elaborate cartoon called Up Goer Five, in which a diagram of the Saturn 5 rocket (the one that took Apollo astronauts to the moon) is labeled with little explanations written in highly simplified language. For example, the helium tanks (which are used for adjusting pressure within the third-stage rocket engine) are described as "THINGS HOLDING THAT KIND OF AIR THAT MAKES YOUR VOICE FUNNY").

Why the childish diction? Because, in creating his rocket diagram, Munroe had limited his descriptions to the 1000 most common English words. Munroe had decided to apply that bare-bones vocabulary to a description of a technical subject, to see what the result would be. The result was pretty funny, if you ask me. Here's a detail from the cartoon, showing the base of the rocket (pardon me, the up-goer):

The cartoon proved popular among Munroe's science-geek fans, and they have started posting descriptions of their technical work to an Up-Goer Five site, using the same restricted vocabulary, and competing to see who can describe the most sophisticated research in the simplest language:

Not to be outdone by his fans, Munroe has expanded on the original concept, and his written a soon-to-be published book called Thing Explainer: Complicated Stuff in Simple Words, which reportedly describes various technical subjects using only the "ten hundred" most common words in the language ("thousand" is not one of those words, you see).

The book isn't out yet, so I don't know whether or not Munroe has tackled the problem of explaining diabetes in this simplified language. Just in case he has not, I would like to try to do it for him, and see if I am up to the task. (Writing this way about a technical subject is much, much harder than it looks.)

I initially tried to do this using an old list of the 1000 commonest words compiled by some association of schoolteachers (a list which I favored because it included the word "sugar", which I needed). But it turns out that Munroe used a more modern list compiled by the folks who maintain Wiktionary. His list, I was disappointed to learn, does not include "sugar", and I had to find a way around that. On the bright side, however, there is an online editing tool which uses the same word list Munroe uses, and checks your text automatically to see if you used any words not on the list. So, although the writing challenge was a little daunting, at least I had an easy means of checking my text as I wrote it.

What is the point of such an exercise, apart from whatever comic value the unnaturally simplified vocabulary creates? Well, maybe it's a worthwhile practice, now and then, to drop the fancy words and see if you can convey the basic idea without them. Abstract language is, perhaps, a little too convenient, and a little too encouraging of vagueness. Sometimes, being able to reach for an abstract word allows us to conceal from ourselves that our grasp of a concept is less precise than it ought to be.

Anyway, for whatever it is worth, here is my attempt at an article about diabetes, using only the "ten hundred" commonest words (which, unfortunately, do not include "sugar" or "test" or "exercise" or "muscle" or "diabetes" or "disease" or "illness" or "health").

So... you have Type Two Sweet Blood Problem!

If you have Sweet Blood Problem, it means your body can't control how sweet your blood is.

There are two types of Sweet Blood Problem. Some people have Type One Sweet Blood Problem, and you get that if you are young. More people have Type Two Sweet Blood Problem, and you get that one if you are kind of old.

You get Type One Sweet Blood Problem if your body attacks your body, and the cells that make the Stuff That Makes Blood Less Sweet all get killed. But I'm not really writing about that kind of Sweet Blood Problem.

I'm more writing about Type Two Sweet Blood Problem. That is the problem you get if the Cells That Make The Body Strong don't respond much to the Stuff That Makes Blood Less Sweet. Those cells should respond, and when they respond they suck in sweet blood, taking it out of the usual blood. But they don't respond as much as they should, so they don't suck in enough sweet blood, and when they don't do that, the usual blood gets too sweet.

Also sometimes if you have Type Two Sweet Blood Problem, the cells that make the Stuff That Makes Blood Less Sweet don't make enough of it. If your Cells That Make The Body Strong don't respond well enough to the stuff, and you don't have enough of it either, then your blood gets really, really sweet.

Why is it bad to have sweet blood? Because sweet blood hurts your body, at least if it stays sweet for a really long time. Many parts of your body are hurt slowly by sweet blood, such as your eyes, and your heart, and the part of your body that cleans your blood and takes water out of your blood and makes you piss, and the parts of your body that you think and feel pain with. These are just some of the parts of your body that are hurt slowly by sweet blood. It may take years of having sweet blood before you know you have hurt your body. And can you fix it then? Sorry, no. More like, you have to live with it. You hurt your body and that's that. And if your heart is one of the parts of your body that you hurt, you might die or something, so it's bad to just let sweet blood hurt your body for a long time. Instead, you have to make your blood not be so sweet, so that your body doesn't get hurt so much.

So, if you have Type Two Sweet Blood Problem, how can you keep your blood from being too sweet all the time and slowly hurting your body?

Well, one thing you can do is not eat so much of the kinds of food that make your blood sweet. You have to figure out which foods do this, and eat less of them, or maybe stop eating some of them at all. If you check your blood to see how sweet it is after you eat, (there are little blood-checking things you can buy at the store that do this), then all you have to do is check after you eat different foods to see what they do to your blood.

Which foods do you need to watch out for? Well, sweet foods make your blood sweet, but also some other foods make your blood sweet even though they don't seem sweet in your mouth. What can I call them? They're foods that aren't from animals, but they're not green, and they're usually white (or maybe light brown) and they may be little bit boring in your mouth. You know the foods I mean?

Anyway those kind of foods make your blood sweet even more than sweet foods do! It's weird, but the reason is that those White Boring Foods get turned into something sweet in your stomach after you eat them, and then they make your blood sweet in minutes. So you have to watch out for sweet foods and also the White Boring Foods.

Another thing you can do is try to make your Cells That Make The Body Strong respond more to the Stuff That Makes Blood Less Sweet. That way, if your blood does get sweet, the Cells That Make Body Strong will suck in the sweet blood and take it out of the usual blood.

But how do you make this happen? One way is to be less heavy, if your body is too heavy. Being too heavy is one of the things that makes your Cells That Make The Body Strong not respond to the Stuff That Makes Blood Less Sweet. (No one knows why, but it's true.)

But the biggest thing you can do is to work out. When you work out, and actually use the Cells That Make The Body Strong, this makes them respond better to the Stuff That Makes Blood Less Sweet. This change to the cells only lasts for a day or two, so you have to work out a lot; it doesn't work if you just do it once in a while.

If you work out a lot, and don't eat too much food (especially sweet foods, and the White Boring Foods), then your blood won't be too sweet, and your body won't get hurt from having Type Two Sweet Blood Problem!


2nd Thursday Update

May 14, 2015


The long haul

Meet Jonathan the tortoise, a long-term resident of the island of St. Helena, photographed in 1902 (when he was at least 50 and more likely 70) and today (when he is thought to be over 180 years old).

That's not even a record for tortoises -- some have lived 250 years or more. Perhaps you're wondering what keeps Jonathan, and others of his type, looking so youthful and vibrant. Why do tortoises live so long?

I don't think "hanging around with young people" is their longevity-booster (though maybe it helps a little). But what else might explain the long duration of a tortoise lifetime?

Various factors play into tortoise longevity. For one thing, tortoises are armored, and animals that are armed for protection from predators tend to have long lifespans. Also, tortoises typically live on islands, where conditions required for a good breeding season may not occur often, and where animals need to live longer simply to be sure of enough opportunities to reproduce.

But the main factor contributing to tortoise longevity may simply be the slow pace of their lives. They have a slow metabolism and a low heart rate; this enables them to survive longer when food is not available. In general, animals with the slowest metabolisms, and especially the slowest heart rates, tend to live longest. (Blue whales live a long time; hummingbirds don't.)

I'm only comparing heart rates between types of animals. It doesn't necessarily follow that, within a given species, the individuals with slower heart rates will live longer. And yet, there is good reason to believe that, for a human being, a slower heart rate is better.

The Mayo Clinic website defines the normal range for resting heart rate pretty broadly (from 60 to 100 beats per minute), but they say that it's better to be towards the low end of that range, because a slower resting heart rate indicates a more efficient heart function and better cardiovascular fitness (they point out that athletes can have resting heart rates as low as 40).

My own resting heart rate has tended to be in the 55-65 range since I began my exercise program (it was considerably higher before that). It may seem paradoxical that exercise, which temporarily boosts your heart rate, would work to slow down your heart rate the rest of the time. The explanation is that the body adapts itself to exercise by expanding blood vessels and growing additional ones; it also strengthens the heart. The end result is that the heart is able to move more blood volume through the body for each contraction, and it simply doesn't have to pump as fast anymore, to achieve the level of circulation the body needs at rest.

So, as tortoises have been teaching hares for years, slow and steady wins the race!


Anemia and A1c

Anemia is usually defined as an insufficient number of red blood cells in circulation, or an insufficient mass of hemoglobin within the red blood cells. It's more of a symptom than a disease; various health problems (including blood loss) can result in anemia, so it's a pretty common condition. Something like 13% of men and 29% of women have some form of anemia.

So it is of some significance that anemia can distort the results of a hemoglobin A1c test. New research indicates that anemia can alter the relationship between average blood sugar level and the rate of hemoglobin glycation. In other words, a hemoglobin A1c test on an anemic person may yield an exaggerated estimate of average blood sugar. The error can be large enough for a person with normal blood sugar to get an A1c result supporting a diabetes diagnosis.

Doctors are being urged to consider anemia as a possible alternative explanation, before diagnosing or treating diabetes on the basis of the A1c test result alone.

However, I would urge diabetes patients not to dismiss an undesirable A1c result on the assumption that "I'm just a little anemic". If you're anemic enough to be getting a misleading A1c result, you're anemic enough to need treatment for your anemia.


1st Thursday Update

May 07, 2015


Real life

Last weekend I was hiking in the state park, and I heard a report from a passing hiker that a woman in the park had fallen and hit her head on a rock, and apparently had a concussion -- she was having trouble seeing. She needed a medical evacuation. A helicopter had been called (the terrain was too rough for a wheeled ambulance to get in there).

I didn't see how a helicopter was going to get in there, either -- the trail the woman was reported to be on is in a narrow and densely-forested canyon. Even if the helicopter could spot her under the canopy of tree branches, they wouldn't be able to land. There was no clear spot that was even remotely level.

The helicopter did arrive soon, and seemingly it had a very difficult time finding the victim; I heard the thing meandering up and down the canyon for several minutes. But apparently they found her, and were able to lower a cable and hoist her up. I was able to capture a few clear pictures of the operation (I was much farther from it than the pictures suggest -- my camera has a good zoom lens.)

I don't know if the injured woman had been running, hiking, or mountain-biking. I suppose it's possible to fall down and bang your head on a rock no matter which of those things you're doing.

It's always depressing to me when people get badly hurt exercising. They're out there doing the right thing, to keep themselves healthy, and then an accident undoes everything they've been trying to accomplish.

I certainly don't mean to suggest that it's better, after all, to stick to the couch, because an active life is a risky life. After all, everything you can do (including doing nothing) is risky in its own way. But we do need to think about what sort of risks we're willing to take in our lives, and what benefit we can realistically get from taking them.

I made a couple of attempts at mountain-biking in that park, and I found it to be too scary and too hard on the body. My wrists ached from gripping the handlebars while bouncing along the rocky trails. And it was way too easy to fall down on rough terrain. If I had stayed with it, I'm sure it would have been me they'd have to helicopter out of there. I know plenty of people who go mountain-biking in that park regularly, and they've never been seriously hurt, but they seem to have a skill at it, or a confidence at it, that I lack. It's too risky for me, and I don't expect ever to try it again.

I do go running and hiking in there. I've taken falls while running, receiving injuries that were a little painful but not serious. I haven't taken a fall while hiking, though I suppose my time may come. Anyway, I feel as if I'm able to accept the risk level associated with running and hiking, but not able to accept the risk level associated with mountain-biking. So that's where I draw the line. Others can draw it wherever they are comfortable drawing it.

I certainly think that the risk level associated with running and hiking is lower than the risk level associated with doing nothing.


Diet vs. Exercise

Researchers at Saint Louis University, who were studying improvements in insulin sensitivity brought on by exercise and also by caloric restriction, decided to do a head-to-head comparison, to see how much impact either of those things had on its own. The study looked at overweight, originally sedentary, middle-aged and older people who had lost weight by different methods.

The result: losing a given amount of weight by means of caloric restriction, or by means of exercise, improves insulin sensitivity, and by about the same amount (although exercise has a slight edge). Perhaps surprisingly, these effects are additive: combining exercise with caloric restriction improves insulin sensitivity twice as much as either does by itself.

The study authors couldn't resist adding a gloomy parting shot: "However, because data from participants who withdrew from the study and from those who did not adhere to the intervention were excluded, the results may be limited to individuals who are capable of adhering to a healthy lifestyle intervention."

In other words: let's not get too excited about this, because some people aren't going to do it! Funny, reports about how marvelously effective a pill is don't usually end with a sorrowful reminder that the pill won't help people who don't take it.


Diabetes screening tools

That's Giacomo Puccini, the Italian opera composer. In 1903, during a time when he was trying to finish his opera Madama Butterfly, he was riding in a car with his wife and son, on the road from Lucca to Torre del Lago. The driver misjudged a curve; the car left the road and dropped down an embankment, rolling over. The most seriously injured passenger was Puccini himself, who had a severe leg fracture and was frighteningly pinned under the vehicle with metal pressing down on his chest. After he was rescued and transferred to a hospital to be treated for his traumatic injuries, the doctors discovered something unexpected: the composer had diabetes.

Well, that was 1904. Medicine was pretty primitive then. They didn't screen people for problems such as diabetes; you found out you were diabetic because some random event brought you into a situation where doctors were looking at your blood sugar levels. That's not how people find out they have diabetes these days, is it? Is it?

Actually, pretty often that's exactly how people find out they have diabetes: it's a random discovery, made while they are being treated for some other problem. Doctors do try to screen patients for diabetes, but the screening process misses a lot of diabetes cases, so a lot of people who have diabetes don't know it, and they might not find out for a long time. Then, some random event occurs -- they've fallen while trail-running and they have to be airlifted to a hospital, say -- and while they're being treated for whatever happened to them, the doctors find out that there's a blood-sugar problem going on here as well.

This isn't a good thing. If you want to get your blood sugar back under control, your chances of succeeding at that are a lot higher if you don't wait too long to get started. The sooner you find out you have diabetes, and the sooner you start trying to improve the situation, the likelier you are to succeed. We need better diabetes screening methods than we've got.

Why does diabetes screening often overlook cases of diabetes? Because diabetes screening typically employs the wrong tool.

Diabetes screening usually consists of a test of fasting plasma glucose -- a volatile quantity which, on a good day, will test normal even in the case of a patient who is losing control of blood sugar and would likely get an alarmingly high non-fasting result. When you are in the process of becoming diabetic, your glucose levels start to become increasingly high after meals, without your fasting results being (at first) affected. The fasting result is often the last thing to go -- it can yield normal results long after your average glucose levels the rest of the time have become unacceptably high.

Canadian researchers have found that the hemoglobin A1c test (which reflects average glucose levels over time, and is not thrown off by short-term fluctuations occurring at the time the test sample is collected) can find three times as many "hidden" diabetes cases as plasma glucose tests can. This is in line with the findings of previous studies that say we should be using the A1c test as a screening tool, if we really want to find out, as early as possible, who has diabetes and who doesn't.

So why hasn't the medical profession adopted the A1c test as a standard screening tool? Two possible explanations suggest themselves. One is that, because A1c testing is more expensive than glucose testing, the health insurance industry doesn't want to have to cover it.

The other possible explanation is that the health insurance industry really doesn't want to know how much undiagnosed diabetes is out there. The advantages of early diagnosis are obvious in the case of the patient, but less obvious in the case of the insurer. What hasn't been diagnosed doesn't have to be covered; perhaps it is in the best interest of insurers (at least in the short term) to delay diagnosis, so that nobody is on the hook for treating the disease or paying for that treatment.

Anyway, it's pretty clear that using fasting plasma glucose as a screening tool is an inadequate solution. We ought to be using the A1c test for that.


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