Every fall, the National Library of Medicine performs maintenance for all PubMed articles. This maintenance includes correcting errors made during the indexing process (ie, fixing an author’s misspelled name) and updating articles with new or revised subject headings. If you think about how quickly our understanding of diseases and biomedicine has changed in the last few decades, it’s clear that the controlled vocabulary used to describe this literature must also grow and change.
Currently there are over 26,000 MeSH terms and new terms are added every year. Some new terms will replace or specify older, less accurate, or antiquated terms. In 2013, the terms Ageism, Social Discrimination, and Racism will be added where previously the only heading available was Prejudice.
Other headings are simply new concepts being discussed more regularly in the literature. These might not be “cutting edge” issues in research any more, but they have become wide-spread enough in the literature that indexers have created new headings for them. In 2013, for example, there will be the new MeSH terms, Crowdsourcing, Human papillomavirus DNA Tests, Epigenetic Repression, and subjects that describe the growing literature on medical marijuana – Cannabinoid Receptor Agonists and Cannabinoid Receptor Modulators.
These new subjects are either suggested for addition by readers (yes, YOU can suggest new terms!) or by subject-specialist indexers who find gaps in current terminology. The librarians at National Jewish Health pay close attention to these changes so that our literature searches remain as accurate as possible!