" The breakthrough study was done by Dr. Peter Elwood and a team from the Cochrane Institute of Primary Care and Public Health, Cardiff University, United Kingdom, and released in December 2013. For thirty years, these researchers followed 2,235 men living in Caerphilly, Wales, aged 45 to 59, and observed the impact of five activities on their health and on whether they developed dementia or cognitive decline, heart disease, cancer, or early death. The Cardiff study was meticulous, examining the men at intervals over the thirty years, and if they showed signs of cognitive decline or dementia, they were sent for detailed clinical assessments of high quality. It overcame study design problems from eleven previous studies (discussed in the endnotes). Results showed that if the men did four or five of the following behaviors, their risk for cognitive (mental) decline and dementia (including Alzheimer’s) fell by 60 percent: "

― Norman Doidge , The Brain's Way of Healing: Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity