I've read on multiple web sites that Asians have larger pancreas than europeans or africans. Africans having the smallest pancreas of all.
This is why african-americans have higher diabetes rates than caucasian-americans.
I've read that the ratio of upper body to lower body has something to do with this, too. The larger/longer your upper body and shorter your legs the more likely you have a larger pancreas and can tolerate a higher carb diet longer without becoming diabetic.
Africans seems to have long legs and shorter upper bodies, which would give them the smallest pancreas.
Not sure if this is all true, just things I've been reading around on the net.