A highly regarded report published by The Lancet Commission on Dementia Prevention, Intervention and Care called dementia “the greatest global challenge for health and social care in the 21st century.” 1 Ask friends and loved ones of the estimated 50 million people worldwide who have dementia, and they'll no doubt back it up — with stories about the worry, stress, sadness and devastation that dementia leaves in its wake. Formed to provide recommendations for the ...