They've also used the same study template in Montana and Colorado. Always people admitted to the hospital, not total heart attacks and always for some rather arbitrary local area. In tje Colorado case you can show that total deaths from heart attacks have fluctuated in the past more than they did over the study period.
Not especially convincing but they want very much to find scientific backing for their preconceived notion. The tortured data are screaming.
The famous Framingham studies were all done on a local population and formed the basis for a deeper understanding of many diseases. Thousands of research studies cite the Framingham data.
If the study had been done on a diverse population, you would have criticized it for being too diverse and when it is done on a tightly controlled population, you criticize it for not being diverse enough.