Saturday, October 3, 2009

BMI and Stupid Assumptions

Excessive exercise often accompanies eating disorders. You wouldn't think it would be necessary to point out that this is not healthy, but as the ED Bites blog says, it's often hard for people to grasp that exercise isn't automatically nor universally a healthy behaviour.

A few weeks ago, we had a seminar with a case study (an invented case) about a woman with a BMI of 20. The medical students presenting this case described this as a "normal, healthy BMI" and then recommended that she increase her exercise as part of a list of general recommendations for improving health. The seminar leader, Dr. P, a family physician who had written these cases as composites from real scenarios, did not disagree.

A friend of mine with background in eating disorders work did say to the group that a BMI of 20 is very often neither normal nor healthy. Any woman presenting to her family doctor with a BMI of 20 deserves a screening for eating disordered behaviours rather than a blanket recommendation to increase exercise.

Another case during the seminar described a patient with a BMI of 32. At one point there was a list of behaviours that were affecting his health. Obesity was listed. I pointed out to the group that obesity is not, in fact, a behaviour. Then, as the case continued, Dr. P said that the individual's obesity would limit his ability to do his job as a construction worker. I asked why, and was told that he would not be fit enough to do his job. Dr. P did not seem to buy the argument that fitness is not the same as obesity.

The whole thing was incredibly irritating. Note that we're talking about a BMI of 32 here. In fact, every obese person described in the seminar had a BMI of 32 or 33. Apparently people larger than that are too unbelievably enormous to even consider... Thanks to Dee for the photo below, an example of a man with a BMI of 32.

Edited to Add: A number of commenters objected to my statement above about a BMI of 20 triggering screening for an eating disorder. That is not the same as assuming this patient has an eating disorder. She probably doesn't. However, given that anorexia nervosa is a relatively prevalent (0.5 to 1% prevalence means all family practitioners will see several cases) and very severe illness, I do think that every woman with a BMI on the low or low-normal side deserves a screen for eating-disordered behaviours. Screening in this case would be a minute or two spent asking questions about weight loss, amenorrhea, eating patterns, and exercise patterns.

Similarly, I screen everybody with a sleep complaint for major depression, and anybody who has had a traumatic event for PTSD. The vast majority of patients won't have depression or PTSD. But if 1/100 has a good chance of it then these are serious enough risks that I think screening is warranted. One problem with eating disorders is that it's really difficult to find prevalence rates and the studies vary widely about how common these illnesses are. I'd rather err on the side of screening too many people than miss one.

An additional issue here, unique to eating disorders, is that physicians do a pretty poor job of identifying patients until they get really, really sick. Knowing that there's a good chance I am already missing a lot of patients with these illnesses tends to lower my threshold for screening for them.

Thursday, September 10, 2009

Blood Pressure

Recently, during my Obstetrics rotation, I saw a woman with very high blood pressure. She was 36 weeks pregnant. I wondered whether her blood pressure was elevated due to the cuff being too small. I asked around, and a few people vaguely remembered that there was once a large cuff but they weren't sure where it was. I eventually found a thigh-sized cuff which gave a much lower reading. It may have been inaccurate too, because the thigh cuffs tend to be too wide for fat arms (unless the fat arms happen to belong to a very tall person).

Nobody else really seemed to think the lack of an appropriate BP cuff was a big deal. I think it's not just a big deal, but totally unacceptable. There needs to be a large cuff available in every ward in every hospital that treats a general adult population. Too-small cuffs directly affect patient care.

Here's a pie-in-the-sky dream: I wish we (the fat acceptance & HAES communities) could raise money to send one-piece large-cuff sphygmomanometers (like the Welch-Allyn DS44-12) to hospitals and clinics, along with a letter discussing the importance of providing appropriate care to large patients!

Edited to add: Thanks to living400lbs for providing the link to Well-Rounded Mama's excellent series about the need for large blood pressure cuffs.

Tuesday, September 8, 2009

Weight Stability

A while back, I attended a tutorial where we discussed a fictional patient case. In the introduction, the patient is described as having gained 45 lbs over the past three years. Most students seem to believe that this is a reasonable amount for someone to gain simply based on becoming more sedentary and adopting a worse eating style.

I strongly disagreed. I think that the vast majority of the time when someone has a stable weight for years and then suddenly gains a significant amount of weight (175 to 225 lbs, in this case) it's almost always going to have a medical cause. Our bodies cling to our setpoints quite voraciously. It's HARD to gain that much weight from a stable beginning. Of course, there are exceptions: chronic dieters, psychiatric illnesses such as depression, and individuals who happen to be unusual weight gainers or losers.

It took me a while to figure out why this was making me so angry. I think that this attitude that it's so easy to just gain 50 lbs if you 'let yourself go' is behind this idea that somebody who is thin is actively doing something right to maintain their weight. So if somebody is thin it follows that they are maintaining a 'good' lifestyle. If they adopted a 'bad' lifestyle, they would become fat. That is, naturally thin folks have a vested interest in believing that it is easy to gain weight because the conclusion drawn is that they have a good, virtuous lifestyle that has earned them the right to be thin.

Of course, if somebody unintentionally LOSES any weight (even 10 lbs lets say) we'd be all over a medical cause for it!

Monday, August 31, 2009

Vitamin D

Vitamin D is a fat-soluble vitamin. When fat individuals get vitamin D (whether from skin, food, or supplements) much of it gets squirreled away into fat stores rather than in circulation. As a result, fat people are far more likely to be vitamin D deficient than smaller folks.

This makes the paper Vitamin D Status and Cardiometabolic Risk Factors in the United States Adolescent Population (from September 2009's Pediatrics) particularly interesting. It concludes:

Low serum vitamin D in US adolescents is strongly associated with hypertension, hyperglycemia, and metabolic syndrome, independent of adiposity.

I wonder how much of the supposed metabolic risk of being fat is really a result of vitamin D deficiency? The evidence is just emerging, so nobody knows for sure yet. Still, fascinating stuff.

Thursday, August 20, 2009

Small Victories

It's nice to occasionally have a HAES victory, even when it's small. I'm doing a rotation in a psychiatric ward this month, and in their examination room there was a huge BMI poster on the door. It was the same kind of poster you see everywhere with a graph to see how fat you are, and a table explaining that anything over a BMI of 25 means you need to lose weight.

BMI posters are incredibly irritating no matter where they are, but in a psychiatric ward it makes even less sense: People are already feeling pretty badly about themselves, let's berate them about their weight! And if they are in the psychiatric ward to treat an eating disorder, even better to remind them that they might be fat! So, I asked the individual in charge if it could be removed, and she took a look, agreed with me, and pulled the poster down.

One BMI poster less in the world is one of those small but very satisfying victories.

Friday, May 1, 2009


I am currently finishing up my pediatrics rotation. While I absolutely love working with kids, the constant focus on The Obesity Epidemic has been infuriating and exhausting. I gave a presentation to the department today, and while I usually talk directly about HAES in these contexts, I just couldn't cope with that kind of hostility after over a month of it. So I spoke about a related topic -- treatment of Anorexia Nervosa.

I spoke about Family Based Treatment, and how it is the only treatment for AN that has reasonable evidence behind it. I discussed how FBT works. I talked about the absence of evidence that families of teens with AN are themselves pathologic. Many of the audience members had a big problem with this. The argument that most families have pathology, particularly if you put a big microscope under them, so you shouldn't use anecdotal evidence to villify families of teens with AN was not convincing apparently. Plus, you know, the lack of evidence.

Anyways, that was all fine. I can deal with that. But then, just as I'm finishing, one of the pediatricians says, "You know, I bet that this behavioural approach would work really well for obesity as well. You schedule meals at particular times, you watch the kids, and you force them to normalize their eating." An argument followed where I stated that there is no evidence that kids who are fat eat worse than their thin peers. The pediatrician and several others were simply like, "You're wrong." Fine. Even that I can deal with!

But just before the pediatrician left, I was making the point that there is a huge difference between AN -- a severe mental illness with a high mortality and even higher morbidity -- and obesity -- a supposed risk factor for illness that describes one end of the normal spectrum of human variation. And the pediatrician said, very confidently, that he didn't think AN was worse than obesity in the long run. Nobody else seemed to understand how profoundly offensive, never mind ridiculous, that statement is.

Sigh. There are so many days where I feel like I'm living in a parallel world, and I start wondering whether I really am the crazy one. I'm ready for pediatrics to end.

Tuesday, February 10, 2009

Not much to report from medical school lately. There's an interesting study described in the NYTimes about how "health scares reduce smoking but not obesity": It's interesting how they ignore the obvious conclusion: smoking is a modifiable behaviour; weight isn't.