Between 2010 and 2015, the worldwide costs of dementia increased by about 35%, from $604 billion in 2010 to $818 billion in 2015. An estimated 46.8 million people worldwide have dementia. These costs are projected to exceed $1 trillion by 2018. About 86% of the costs, $715 billion, occur in high-income countries. Direct medical costs are estimated at $159.2 billion, representing 19.5% of the total costs. Direct social sector costs are estimated at $327.9 billion, representing 40.1% of the total costs. Informal care costs are estimated at $330.8 billion, representing 40.4% of . . .