Publications on dementia in Medline 1974-2009: a quantitative bibliometric study.

Object: The aim is to describe the development of the scientific literature on dementia.

Methods: We present a quantitative, bibliometric study of the literature on dementia, based on Medline, covering 36 years (1974-2009). Two samples of references to dementia papers were retrieved: The main sample based on the MeSH term Dementia holds more than 88,500 references. We have compared the annual additions of references on dementia with the addition to total Medline. Changes of 'the Dementia to Medline ratio' (%) give the best information on the development.

Results: Publications on dementia increased 5.6 times faster than Medline. Most of this relative acceleration took place during 1980-1997, when the references on dementia increased from 0.17 to 0.78%. During the recent 12 years, the publications on dementia have been keeping pace with Medline and have stabilized around 0.8%.

Conclusions: We have shown a large increase of the literature on dementia, relative both to the development of all medical research and to all psychiatric research. The bibliometric approach may be questioned as quantitative methods treat articles as being of equal value, what is not true. If, for example, during a certain period, the research output is 'inflated' by a great number of repetitive papers, the quantitative method will give an unfair picture of the development. Our relative method, however, will give relevant results as, at each point of time, the proportion of 'valuable research' ought to be about the same in the dementia group as in total Medline.