Thursday, August 31, 2006

Science Thursdays: Fat Chance

I'm trying my hand at a recurring piece here in ONAF: science writing every Thursday. Let me know if my idea is a good one or not.

Either way, today I rant about obesity measurements.

The News and Observer recently reported that North Carolina is the 14th fattest state in the country, with 63% of our residents tipping the virtual scales as officially overweight or obese. Mississippi took top dishonors with 67%, while outdoors-friendly Colorado was at the relatively shapely bottom with 55%. Combined with a recent report that being just a little bit overweight can have serious health effects.

Then again, it may not be such a bad thing. A recent study from a Brazilian team demonstrated that people classified as "overweight" are actually at lower risk for heart disease than those classified as normal. So should we all break out the Twinkies and save our hearts? Or is there something else at work here?

The Brazilians certainly think so. The problem, they say, lies in the instrument used to classify people as "obese" or "overweight"; the body mass index (BMI).

Few serious doctors doubt the link between fattiness and diseases such as type 2 diabetes, heart disease, hypertension, and other ugly stuff. In an ideal world, we'd be able to find out how much fat we have in our bodies and diagnose ourselves from there. This function is served by the body fat percentage, which is the mass of fat in your body divided by your total mass. It sounds simple, but it's very difficult to measure. Some relatively less annoying methods for estimating body fat percentage are chronicled in the Wikipedia article, but as the article states, the only truly accurate way of going about it is by using dual energy X-ray absorptiometry, or a bone density scan. You probably don't have one of those machines lying around. Most people don't - it's costly, and doctors don't generally want to waste a DXA on someone who doesn't have osteoporosis.

You probably do, however, have a scale, and this is where the BMI comes in. Invented by Belgian Adolphe Quetelet during the mid-19th century, it was intended as an estimate of how overweight someone was. The BMI is simply your weight in kilograms divided by the square of your height in meters. If that's greater than 25, you're overweight. Over 30, you're obese. Nice and simple.

And it works, too, provided you make a simple assumption: everyone has the same ratio of muscle to fat. And this is where the BMI breaks down. Since muscle is more dense than fat, someone with more muscle than average can easily tip the scales as "overweight" even if they don't have any more fat than someone who is "normal." Similarly, someone who has a good deal of fat but very little muscle could sneak in under the limit and be mistakenly classified as "normal." Dallas Cowboys wide receiver Terrell Owens, for example, has a BMI of 28.2 - substantially overweight. Saints running back Reggie Bush tips the scales at 27.9. Poor 'Skins running back Clinton Portis has a BMI of 30 - he's obese.

Of course, no one in their right mind would accuse these athletes of being fatasses. No one would think to believe the BMI diagnosis where they're concerned. What the Brazilian study demonstrated was that the BMI index was so deeply flawed that its usage was suspect even among everyday people. Perhaps the BMI works among generally sedentary Americans. But if you take a group of people who have gained muscle through more regular physical activity - say, Brazilians - the BMI loses its effectiveness.

Furthermore, the BMI ignores the differences between acceptable fat levels for men and women. Women are generally supposed to be fattier than men; men should limit themselves to a body-fat percentage of 17%, while women can get away with 24% and still be considered fit. This is a distinction that is lost on most people who use BMI to determine risk factors, however, and one that isn't used in determining statistics like the ones I cited earlier.

We need a better way to estimate one's risk of disease from obesity. Fortunately, there are several options. Scientists have proposed the use of waist circumference, waist circumference-to-height ratio, and the waist circumference-to-hip circumference ratio. A German group found that of these measures, waist circumference-to-height ratio was the best at predicting risk of heart disease. So divide your waist circumference by your height. Men, if this number is higher than 0.55, you're in trouble. Ladies, your magic number is 0.53.

This isn't perfect, mind you; shorter people and people with thicker builds are more likely to be flagged by this method. It has its problems, just like BMI. However, in the absence of a DXA machine in every house, quick-and-dirty methods like the waist-to-height ratio and BMI will have to do. Just take them for what they are: an approximation. And most importantly, know their limitations. You'll be fine as long as you don't think that BMI is the alpha and omega of fitness. Now if someone would only tell that to the BMI-crazed statkeepers out there...

Monday, August 28, 2006

Jefferson Is Falling Down...

Fellow Jefferson alums: thanks to today's Wall Street Journal, our school is now known nationwide as the elite public school that's falling apart. Next on TJ's list of requirements: hard hats for its students.

Random Music Post

The Guardian reports that, according to a new poll, the greatest guitar solo of all time is... David Gilmour's solo at the end of Pink Floyd's "Comfortably Numb." Which, since most people automatically default to "Stairway," is quite remarkable. Here's the rest of the list:

2. Slash, "Sweet Child O' Mine" (Guns 'N' Roses)
3. Gary Rossington/Allen Collins, "Free Bird" (Lynyrd Skynyrd)
4. Eddie Van Halen, "Eruption" (Van Halen)
5. Slash, "November Rain" (Guns 'N' Roses)
6. Jimmy Page, "Stairway to Heaven" (Led Zeppelin
7. Mark Knopfler, "Sultans of Swing" (Dire Straits)
8. Martin Barre, "Aqualung" (Jethro Tull)
9. Joe Walsh, "Hotel California" (Eagles)
10. Ritchie Blackmore, "Child in Time" (Deep Purple)

Some surprises, some standards. Glad to see the Aqualung solo finally getting some respect - I think the last list I saw had it at #25. Personally, I think that Page's solo in "Black Dog" is a hell of a lot better than his "Stairway" solo, and Terry Kath's excellent solo in "25 or 6 to 4" is ridiculously underrated. And I'm somewhat surprised that Carlos Santana and Jimi Hendrix both got shut out of the top 10. It's also worth noting that there are no songs on this list recorded after 1990. Anyone else know any solos that don't get the respect they deserve?

Stuart Scott Is My Opening Act

I usually go out to karaoke on Sunday nights at Fat Daddy's here in Raleigh. Tonight, however, the senior PGA - er, sorry, "Champions Tour" - Jimmy V Celebrity Golf Classic decided to hold their afterparty at Fat Daddy's. So I found myself in a crowd that included Charles Barkley and ESPN anchors Stuart Scott and Trey Wingo. Barkley picked up the drink tab for everyone, and Scott, Wingo, and the tournament organizers sang several songs. Scott sang Sister Hazel's "All For You" right before my rendition of Warren Zevon's "Werewolves of London." So that was cool.

Anyway, I sang to Charles Barkley with Stuart Scott opening. That's all you need to know.

Friday, August 25, 2006

In Defense of Absurd Security Regulations

Bruce Schneier writes this interesting piece on our response to terrorism. Essentially, he states that by being terrified and obsessing over a relatively uncommon threat, we're giving the terrorists what they want. Most of the points that Schneier makes are dead-on. Those first two cases Schneier lists are downright scary, folks, and indicative of the fact that we all definitely need to chill out. Anyone who objects to flying on a plane with a Muslim simply because of their religion or appearance ought to have their ass kicked.

There is one point I want to address, however. Schneier lampoons security measures like shoe x-rays and liquid removal as "pointless." While I agree that the measures aren't going to stop a well-thought-out terrorist attack, I would argue that the current security measures are not completely pointless. Schneier's idea of fighting terrorism with police work and intelligence is good, and we do that currently, but people don't see it. The mostly cosmetic security measures are there for three reasons. First, they're an idiot check; we may not catch the smart terrorists, but we can definitely stop the stupid ones. Second, it lets potential terrorists know that we're after them, and may therefore serve as something of a deterrent.

But lastly, airport security measures are for the most part cosmetic; they let people know that the government is doing something, and in that way foster confidence that the government can keep us safe. We know that a terrorist plot involving a shampoo bottle is far-fetched and unlikely to succeed (and if you don't, I suggest following the links in Schneier's article to chemists who rightfully ridicule the idea). However, it's good to see evidence that the government is responding to threats instead of being catatonic. If Schneier thinks we're skittish now, imagine what we'd be like if we didn't have that symbolic reassurance.

The problem, of course, arises when people (and the government) become so obsessed with the cosmetic measures that they forget to take the important steps, and in that sense I agree with Schneier. So I don't completely contest the point; I just think that the money going towards new airport security screening methods is not being completely wasted.

Thursday, August 24, 2006

Warning: Geekiness Ahead

Is there a way out of the stem cell debate? Robert Lanza hopes so.

A research team headed by Lanza has hatched a new method for producing stem cells that does not involve the destruction of human embryos. Normally, the creation of a stem cell line - a colony of living stem cells with the potential to become human tissue - involves destroying a relatively mature embryo and extracting the stem cells. Lanza instead removes one cell from a younger embryo and induces it to form a stem-cell line. This allows the embryo to continue to grow normally. Nature's Helen Pearson reports (link may not be accessible outside NCSU) that the cell lines have lasted for eight months and have formed different kinds of human tissue.

Of course, the viability of the method has yet to be proven. As Rick Weiss reports (link above), the conditions of the experiment involve contaminants that might make the organs produced unusable. And as Pearson reports, the experimentalists only got two stem-cell lines out of 16 in-vitro fertilization (IVF) embryos. This is horribly inefficient, and the extraction techniques will have to improve if this method is to compete with the current method in the scientists' minds.

Furthermore, no one is sure whether extracting a cell from an embryo at that stage is harmful to the development of the embryo. Lanza claims that the process is actually fairly common in current IVF practice, but he also says that he wants to improve efficiency by taking more than one cell out of the embryo. At that point, it is uncertain what would happen to the embryo's development.

You would think this would satisfy those concerned with the destruction of embryos for therapeutic purposes, right? Not so fast. Some believe that a cell taken from an embryo can itself become an embryo under the right conditions, and so using such a cell would still constitute the destruction of human life. This is a somewhat silly objection; there is no real evidence that this development could occur, and it almost certainly could not occur without some sort of outside encouragement. It is similar to saying that women should not ovulate because their eggs could become human embryos "under the right conditions." And even if it were possible, allowing it to occur would constitute human cloning, which is already taboo. Those who raise this objection are probably just grasping at straws.

A more serious objection is the one raised by the Bush administration in response to the research. According to Weiss, the White House responded to the research with a statement that "any use of human embryos for research purposes raises serious ethical concerns" and that he would just as soon see stem cells developed "without the need for human embryos." This is a legitimate objection, but one that is still on shaky ground from a logical standpoint. Humans give up their cells for scientific research or for other purposes on a regular basis. Babies give up blood cells for disease analysis. Even fetuses often give up some of their genetic material to scientific analysis - this process, known as amniocentesis, is a relatively common part of modern pregnancy. If the embryo's development is not harmed by the cell extraction, as Lanza claims, then how is using an extracted cell for scientific purposes any more unethical than any other use of a person's cells? And if the Bush administration is correct and life begins at conception, why is it any less ethical to take a cell from a person thirty hours after fertilization than it is to take a cell from a person thirty years after conception?

More science news:

- In a rare triumph of science over small-minded politics, the FDA approved the sale of the emergency contraceptive pill over-the-counter to women over 18. There is some grumbling that the pill isn't available to everyone, but the effect of the hormone boost to younger women is uncertain, and so women under 18 will not be able to purchase the pill. Fair enough. However, there was absolutely no scientific reason for restricting the sale of the emergency contraceptive to adult women. The reasons given for the holdup are frivolous at best; the accusation that the pill causes an "early abortion" by preventing a fertilized egg from implanting in the uterus ignores the fact that fertilized eggs often fail to implant in the uterus naturally, and accusing "the pill" of increasing promiscuity is akin to blaming Kevlar vests for gun violence. The whole difficulty of the process highlights how deeply flawed the FDA approval process is, and how it needs to be simplified, made more transparent, and limited to considering scientific objections.

- Pluto has been voted off the galactic island. Apparently, its orbit is too dependent upon Neptune (whose orbital path it crosses; in fact, until recently, Pluto was nearer the sun than Neptune). However, all is not lost for everyone's favorite iceball: it will now be considered a "dwarf planet." Which means it will be renamed "Sneezy." The asteroid Ceres will be a dwarf planet as well. Perhaps it will be "Happy." And I'm all for renaming the cumbersomely named 2003 UB313 "Dopey."

Tuesday, August 22, 2006

Remember Me?

I don't know if anyone is still reading this, but I'm back from my time off.

Anyway, since the TV news sources went a few days without broadcasting any actual news last weekend (instead choosing to focus all their energy on a single nine-year-old murder case in Colorado), I figured I'd fill people in on what happened during those few days:

- The cease-fire in Lebanon ran into trouble as Israel bombed a Bekaa Valley Hezbollah stronghold. Apparently, Hezbollah was using the location to import weaponry from Syria and/or Iran. Perhaps we should be a little bit clearer on the concept of "cease-fire." Bombings and weapons trafficking are not cease-fire activities. And here's hoping the Lebanese people realize that as long as Hezbollah continues to have weapons, Lebanon will never be a functioning state. Some experts define a state as an entity with a monopoly on the legitimate use of force - if Lebanon allows Hezbollah to continue using force against Israel (or anyone for that matter), it has no power.

The irony here is that the Lebanese are so fearful of Israel that they run into the waiting arms of Hezbollah, whose entire reason for existence is to provoke Israel into doing things that make the Lebanese people fearful. In a sense, Lebanese fear is self-perpetuating. Lebanon's government could do a lot by disarming Hezbollah and investing more in their own military; it'd be nice if the Lebanese could trust someone besides a bunch of nutty loose cannons with their security.

Reasons I could not be President: I would start an international incident when I got the leaders of Hamas, Hezbollah, Israel, Iran, Lebanon, and the PA in a room together, called them all "fucking idiots," and locked them in said room without food or water until they had resolved their differences. Or when I put Operation Giant Doobie into effect.

- A court in Detroit struck down the warrantless wiretapping program, but allowed it to continue until higher courts weighed in. The Bush administration is predictably calling the decision "partisan" - a bit of cynical hypocrisy from an administration that was allowed to take office by a partisan judicial decision. I guess the Republicans only like partisan judicial decisions that go their way. Oh, and congressional Republicans: none of this would have happened had you actually exercised your powers of oversight. You have no one to blame but yourselves.

Also, does anyone know how FISA's retroactive warrant requirement is such a burden on administration intelligence gathering? It still doesn't seem to me like getting a warrant from a secret court within 72 hours is such an onerous task.

- Budget predictions are in. Looks like we got a windfall this year that kept the budget deficit at a "mere" $260 billion or so. In the long term, we could come close to balancing if Bush's tax cuts are allowed to lapse in 2010 - otherwise, we're looking at a budget deficit in the $700 billion range. Oh, and more money is currently spent on servicing our debt than on all federal anti-poverty programs. (It's about $200 billion right now.) Tax cutters, take note.

- Virginia Senator George Allen was awarded the Mel Gibson Memorial Foot-In-Mouth Award when he referred to Fairfax native S.R. Sidarth, a darker-hued campaign volunteer for opponent Jim Webb, as "macaca" and bade him "welcome to America and the real world of Virginia." Boy, that "welcome to America" bit wasn't condescending to the entire Indian-American community at all, was it? I have the feeling Allen was one brain fart away from making a Slurpee joke. As for what he meant by the "macaca" bit, I quote The Daily Show's Rob Corddry: "I don't know, but it sure as shit sounds racist." (Apparently, a macaca is a kind of African monkey, and so I would definitely treat it as a racist slur if I thought that there was any way in hell George Allen knew what a macaca was.)

- From today, Iran isn't giving up its nuclear program. They say they have a "new formula" for dealing with the issue. The formula, apparently, is this: your indignation + our middle finger + ten years or so of this crap = nuclear weapons. How many years are left on A-Train's term again?

Tuesday, August 01, 2006

Sleepless in Seattle

Apparently, some dipshit decided it would be a good idea to protest Israel's overblown response to the Hezbollah attacks by... wait for it... going on a shooting spree at a Jewish center in Seattle.

Let us deconstruct the reasoning of this shooter:

1) Israel is engaging in excessive violence in the Middle East.
2) I need to do something about it.
3) I am located in Seattle, 6700 miles away from the action.
4) The violence is obviously the fault of Jews in Seattle, who are also 6700 miles away from the action.
5) I will therefore demonstrate how wrong violence is by murdering a Seattle Jew.

Note to any potential shooters who are reading this blog: protesting violence with violence makes you a douchebag. For that matter, protesting anything with violence makes you a douchebag.

Update: One would expect this guy to be a Lebanese Shiite Muslim, right? Actually, he's a Pakistani-American convert to Christianity. Michelle Malkin's goofy conspiracy theories aside (spending months at an evangelical church and getting baptized is one hell of a way to "disguise your faith"), it looks like our shooter was really just your everyday run-of-the-mill confused stupid psychopath.

Speaking of douchebags. If you're the son of a Holocaust denier who has never officially repudiated his father's stance on the issue and are planning to produce a mini-series about the Holocaust, don't blame the Jews for all of the world's wars. It might not be good for business.

A Simple Prop To Occupy Your Mind

Back from Mexico, and promptly proceeding to Phoenix, Nashville, and points west, so this'll be my last post until Aug. 18 unless something weird happens.

First, congratulations to the Congo for voting on a leader. Let's see if the West can avoid trying to kill this one.

Second, the Middle East really needs that doobie. Now. Until then, here's a few questions for you to ponder...

- Why did Israel think that a massive military response that was sure to kill civilians would erode support for Hezbollah in southern Lebanon? Did you not understand that bombing the hell out of southern Lebanon would just convince the Lebanese that Hezbollah is the only thing that can protect them?

- There's plenty of outrage to go around over Israel's excesses. Good. So where's the outrage from the Arab world about Hezbollah's and Hamas' routine murders - homicide bombings (I refuse to call them "suicide"), rockets, and the like? Has the Arab world completely forgotten that Hezbollah is at fault for this little brouhaha too? Until the Arab leaders start condemning acts of violence from their side, we will not have peace...

- What, exactly, do Hezbollah and Hamas think they're accomplishing? I've said it before and I'll say it again - these guys couldn't resist their way out of a paper bag. Every time they get close to making gains, they blow something up and thus piss the opportunity away. I don't envy Mahmoud Abbas' ulcer. I do, however, give the Arabs credit for misplaced disingenuous whining about "Israeli aggression." The Israelis need to learn how to whine effectively instead of blowing stuff up.

Third and finally, congratulations to the brilliant Treasury economists who have discovered that you can't add by subtracting. You have now learned something that every third-grader knows. Well done.