Older dogs often develop a form of dementia that is similar to Alzheimer’s disease. We currently know little about this condition which limits our ability to prevent or manage it. IGF-1 is a hormone that regulates body size in dogs. In studies with humans and other animals, this hormone has been shown to protect the aging brain. The goal of this research is to evaluate whether dogs with lower levels of this hormone have increased risk for dementia. Results of the study will advance knowledge about the causes of dementia in dogs and will inform the development of new treatments to protect senior dog cognitive health.