Dementia and decline . . . and other storiesBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.j5666 (Published 04 January 2018) Cite this as: BMJ 2018;360:j5666
Time trends in dementia
As everyone knows, the number of people who have dementia is rising. The reasons, of course, are that people are living longer and that the likelihood of cognitive decline increases steeply with age. But looked at by cohort of birth, time trends in dementia might be going in the opposite direction. Analysis of incidence of dementia in the Einstein Ageing Study from New York finds that successive generations experience lower rates (JAMA Neurol doi:10.1001/jamaneurol.2017.1964). Whether this decrease in incidence will be large enough to compensate for increasing expectation of life is another matter.
In the real world of clinical research, data collection is often incomplete. There are several ways of dealing with missing values, but the commonest method is simply to exclude participants with incomplete information. An analysis in the American Journal …