The weirdness of statistics

[torquill]

If the predicted frequency of gluten-intolerant individuals (given current data) is 1 in every 250 people... How is it that I know so many of them?

I swear, I know at least eight diagnosed celiacs off the top of my head, which means I missed a few (there's a massive number of undiagnosed ones out there). There's at least one and often more of the confirmed celiacs at most events I attend, and that's not even counting the wheat-sensitive people like me. What gives?

Comments

[tiggerypum.livejournal.com]

The statistics are wrong/outdated?

Somehow you attract each other?

Someone in our food or environment is making more folks react badly?

[luna-torquill.livejournal.com]

1) Wrong is possible, though it's looking like those numbers are (if anything) on the low side. They are current, though.

3) Celiac disease is 90% genetic... so unless we've got mutagens in the water here, it's kind of unlikely. ;)

I guess that leaves 2)... *shrug*

[packy.livejournal.com]

If the expected frequency is 1 in every 250 and you know eight, that suggests you know about 2000 people, which isn't that large a population. Of course, that also presumes the population is completely homogeneous, which, of course, it isn't. You've encountered a more dense portion of the population, whereas I've encountered a less dense portion (seeing as I know, if I recall correctly, two celiacs).

[supersniffles.livejournal.com]

You should have seen the look on my endocrinologist's face when he diagnosed me with PCOS and I told him I knew a half a dozen others with the syndrome.
I'm vote that we attract each other somehow. (You get celiacs, I get crazy hormones.)

[luna-torquill.livejournal.com]

There's a flaw in that logic -- you're assuming that the diagnosis rate, even out here, is 100%. I'd guess it's probably more like 50% at best, possibly lower. For many people, there are no symptoms other than vague ones, maybe not even obviously digestive in nature. It takes a blood test or biopsy to know.

And while I know a decent number of people, I am not regularly in contact with even 2000, let alone 4000 (assuming the 50% diagnosis rate). I'd guess I regularly run into around 200 people tops, and know another 250 through "oh, I've heard of them". My friends circle has shrunk dramatically from what it once was, and I don't socialize often.

So by that, I should (statistically) know two celiacs, who may or may not have been diagnosed. I know eight diagnosed and at least another four to six who haven't been, by extension. That's what's making me go "wtf?"

[luna-torquill.livejournal.com]

I know a lot of women with PCOS too... seems like every time I turn around I meet another one.

Thyroid disorder I could see -- that's pretty rampant, and they're finally diagnosing a lot of people who have suffered for years. But PCOS really isn't (supposed to be) that common.

[foogod.livejournal.com]

I suspect that the genetic factor may not be entirely discountable. Lots of other things are genetic as well, including intelligence and predisposition towards lots of types of interests and behaviors. The genetic diversity of the particular group of people you tend to hang out with is most likely substantially smaller than that of the population as a whole. It's possible that the genetic factors for gluten intolerance follow similar paths to other factors which make for the kind of people you like to know..

I would also point out that you have been part of the whole fibromyalgia/food-alergy/etc community for quite a while now. Are you sure that that hasn't had any influence on coming into contact with some of these people (even indirectly)?

[luna-torquill.livejournal.com]

I wasn't discounting the genetic factor -- I was saying that genetics make the "environmental causes" explanation considerably less likely.

It may be linked to other common factors in this group, I agree -- as may PCOS. It would start to explain the clustering effect.

I've met very few people on the fibro/cfs/mcs axis (and I was counting only celiacs that I've met in person). Most of the affected people I've met are actually associated with the poly crowd, oddly enough -- and I came to that group in a way totally independent of the other.

(I note that, though many fibro/cfs/mcs people have food sensitivities, gluten-bearing grains in particular don't seem to be a terribly common one for them, unless they're sensitive to a huge number of foods.)