If someone wants to replicate this study, they could do so on the Pacific islands where Spam is very popular. I know it to be popular in Hawaii and on Guam, and I suppose it is likewise popular in the Commonwealth of the Northern Marianas Islands, the Federated States of Micronesia, etc.
In the mid-1980s the DrsC were spending a year on Guam when, coincidentally, the Spam cannery in Minnesota went on strike. The Pacific Daily News, Guam's newspaper, headlined the strike. Within a day the grocery stores were sold out of Spam - truly the shelves were bare.
On Guam Spam is known as "typhoon food," food that keeps for years, doesn't get infested by bugs, and can be eaten cold right out of the can when a typhoon tears up the electric lines and distribution systems.
Who knows? Spam may be related to diabetes there, too.
