Comments on: Diabetes and obesity

By: razib

razib — Sat, 28 Nov 2009 13:38:34 +0000

i made some serious errors in estimating the white diabetes rate. i’m trying to fix that now. will post an update. thanks for bringing the error to my attention!

By: bayesian

bayesian — Sat, 28 Nov 2009 12:20:47 +0000

(Razib, feel free to cancel my previous comment)

Why is the white diabetic proportion (per definiton in your comment above) positively correlated (though not too strongly) with the SES markers, when the total correlations (i.e. for whole county population) are negative (as you would expect: higher SES => lower diabetes rate).

I don’t get it – sorry to be so dim, but at least you’ve given me a good humility dose for the day.

By: razib

razib — Fri, 27 Nov 2009 19:31:14 +0000

they're the proportion of individuals within a county who are diagnosed with diabetes (age adjusted i believe). you can find it here. so no, not mortality. as i said above, it's probably the fact that latinos are concentrated in the states with the thinnest whites (in contrast with the blacks). since whites are still a majority in many of these counties, you get a cancellation of the effect. there's no county level data on racial prevalence of diabetes, so i simply estimated it going off standard differences between the ethnic groups (as i said above). this obviously introduces a clear distortion in many areas, where hispanics don't have diabetes at the rates of their state aggregated expectation (e.g., the hispanics rio grande counties of texas seem to be way healthier than hispanics in the rest of the state).

By: Galtonian

Galtonian — Fri, 27 Nov 2009 19:19:55 +0000

Razib, are your CDC data mortality due to diabetes or actual diabetes rates. You show that diabetes is negatively correlated with %Hispanic, perhaps this is true if you are looking at mortality. Remember that Hispanics tend to have lower mortality than would be expected based on their SES/SEP or based on their cognitive ability (mortality rates tend to increase when SES/SEP or cognitive ability decreases). The fact that Hispanics have lower mortality than would be expected is called the Hispanic Paradox.

Check out this paper posted on the Nature Precedings website.

http://precedings.nature.com/documents/2862/version/1

It shows that in California Hispanics have lower mortality than would be expected based on their (rather low) cognitive ability (as measured by 7th grade math test scores). The paper postulates that the surprisingly low mortality rates of Hispanics may be due to their CHRM2 allele that codes for higher vagal nerve activity. The vagal nerve may serve as the mind-body link for connecting cognition to better health (the vagal nerve is the body's own endogenous anti-inflammatory system, thus vagal nerve signaling may prevent atherosclerosis and perhaps some cancers).