https://www.fda.gov/animal-veterinary/animal-health-literacy/questions-answers-fda-center-veterinary-medicines-investigation-possible-connection-between-diet-and
excerpt below
To put this issue into proper context, the American Veterinary Medical Association estimates that there are 77 million pet dogs in the United States. As of April 30, 2019, the FDA has received reports about 560 dogs diagnosed with DCM suspected to be linked to diet. Tens of millions of dogs have been eating dog food without developing DCM. If you are concerned about the diet you are currently feeding your dog, FDA recommends working with your veterinarian, who may consult a board-certified veterinary nutritionist, to determine the best diet for your dog’s need.
