Your ethnic origin is a very strong indicator that you are more or less likely to contract Crohn’s disease. Caucasians from North America, and Eastern European Jews of Ashkenazi descent are primarily the ethnicities at risk.
African-Americans are not at risk, but have increasingly been diagnosed. The disease tends to manifest itself slightly differently in their bodies. Scientists say their increasing diagnosis may have to do with the blending of genes as people travel the world and choose mates of different ethnicities.
It is less common in Asians and Latinos.