In The Lancet today, Renata Sousa and colleagues report on the contribution of chronic diseases to disability in countries with low and middle incomes. The investigators' data are important for demographers, epidemiologists, physicians, psychologists, social workers, public health organisations, non-governmental organisations, and families. In high-income countries, knowledge about the existence of dementia is ubiquitous, and it is clear to many people that the incidence of dementia is projected to triple by mid-century in the USA alone. Alzheimer's societies in developed countries are active in fund raising, research efforts, and in providing important educational materials to families. (Source: LANCET)