MEDLINE Data Changes—2020

This article collects the notable data changes made to MEDLINE during the National Library of Medicine (NLM) annual maintenance known as Year-End Processing (YEP) for 2020:

• MeSH Vocabulary Updated for 2020
• Updated MeSH in MEDLINE Citations
• Changes to MeSH Headings
• New MeSH Headings and Concepts
• MeSH Publication Types
• MeSH Tree Changes
• Special MeSH Projects
• Two MeSH Concepts Merged into One
• Do Not Confuse
• Entry Combination Revisions
• Data Distribution Notes
• New Databank Sources

MeSH Vocabulary Updated for 2020

The MeSH Browser currently points to the 2020 MeSH vocabulary with a link to the 2019 MeSH vocabulary. Searchers should consult the Browser to find MeSH headings of interest and their relationships to other headings. The Browser contains MeSH heading records that may include Scope Notes, Annotations, Entry Terms, History Notes, Allowable Qualifiers (Subheadings), Previous Indexing, and other information. It also includes Subheading records and Supplementary Concept Records (SCRs) for substances, diseases, and organisms that are not MeSH headings.

You can download 2020 MeSH from links on the NLM Data Distribution page for MeSH Data.

For highlights about 2020 MeSH, see What's New for 2020 MeSH (forthcoming).

The PubMed MeSH database and translation tables will be updated to reflect 2020 MeSH by the middle of December when YEP activities are complete and the newly maintained MEDLINE data are available in PubMed.

Updated MeSH in MEDLINE Citations

MEDLINE citations with updated MeSH are anticipated to be in PubMed by mid-December 2019. See "Modifying a Saved Search Strategy" for details on revising My NCBI saved searches.

Changes to MeSH Headings

For 2020, 97 MeSH headings were either changed or deleted and replaced with more up-to-date terminology. During YEP, NLM updates these MeSH headings on MEDLINE citations.

New MeSH Headings and Concepts

293 new MeSH headings, plus two new Publication Types, are added to MeSH in 2020.

A complete list of the new 2020 MeSH headings is available in PDF format, see New Headings with Scope Notes, Annotations and Tree Locations.

Typically, NLM does not retrospectively re-index MEDLINE citations with new MeSH heading concepts. Therefore, searching PubMed for a new MeSH term tagged with [mh] or [majr] effectively limits retrieval to citations indexed after the term was introduced. PubMed Automatic Term Mapping (ATM) expands an untagged subject search to include both MeSH Terms and All Fields index terms and may retrieve relevant citations indexed before the introduction of a new MeSH term. Searchers may consult the MeSH Browser or the MeSH database to see the previous indexing terms most likely used for a particular concept before the new MeSH Heading was introduced.

Changes of particular interest to searchers:

MeSH Publication Types

One new publication type is available for MEDLINE indexing in 2020:

• Randomized Controlled Trial, Veterinary
  • Indexing policy: Use for the original report of the conduct or results of a specific randomized veterinary clinical trial in which animal participants are randomly assigned to receive one or more interventions
  • Use the MeSH headings Clinical Trials, Veterinary as Topic and Randomization for the general design, methodology, economics, etc. of randomized veterinary clinical trials.

One new publication type is available for NLM Cataloging only in 2020:

• Movable Books

Four preferred terms are changed for publication types that are used for MEDLINE Indexing:

• Evaluation Studies to Evaluation Study
• Government Document to Government Publication
• Validation Studies to Validation Study
• Webcasts to Webcast

Thirteen preferred terms are changed for publication types that are used for Cataloging only.

One MeSH heading is changed to a publication type. This publication type is used for Cataloging only. A new "as Topic" MeSH heading was not created.

• Biobibliography as Topic is changed to Biobibliography.

MeSH "as Topic" Headings

Three new "As Topic" MeSH heading are available in 2020:

• Fictional Works as Topic
  Note that the corresponding publication type, Fictional Work, is used for Cataloging only.
• Observational Studies, Veterinary as Topic
• Single-Case Studies as Topic

A total of ten preferred terms are changed for "as Topic" MeSH headings:

Four preferred terms for "as Topic" MeSH headings are changed. Their corresponding publication types are used for MEDLINE indexing:

• Autobiography as Topic to Autobiographies as Topic
• Bibliography as Topic to Bibliographies as Topic
• Biography as Topic to Biographies as Topic
• Duplicate Publication as Topic to Duplicate Publications as Topic

Four additional preferred terms for "as Topic" MeSH headings are changed. Note that their corresponding publication types are used for Cataloging only:

• Diary as Topic to Diaries as Topic
• Exhibits as Topic to Exhibitions as Topic
• Programmed Instruction as Topic to Programmed Instructions as Topic
• Study Guide as Topic to Study Guides as Topic

Two preferred terms for "as Topic" MeSH headings are changed to remove "as Topic" from the string. Note that these headings are not changed to publication types:

• Abstracting and Indexing as Topic to Abstracting and Indexing
• Advertising as Topic to Advertising

MeSH Tree Changes

For a list of new MeSH headings by tree hierarchy, see 2020 New MeSH Headings by Subcategory available in PDF format or plain text format (txt).

For a complete list of all MeSH headings by tree hierarchy, see 2020 MeSH Tree Locations available in PDF format or Excel format (xlsx).

Two tree changes of particular interest include:

MeSH Categories C01, C02, and C03 are consolidated.

• Consolidated the tree nodes for Bacterial Infections and Mycoses [C01], Virus Diseases [C02], Parasitic Diseases [C03] into a single category Infections [C01].
• The preferred term for the MeSH heading Infection is changed to Infections and a new entry term of Infections and Infestations is added.
• The MeSH heading Infections is the new name for category [C01].
• The MeSH headings Bacterial Infections and Mycoses, Virus Diseases, and Parasitic Diseases are repositioned under category Infections [C01].
• This tree reconfiguration will make retrieval for Infections inclusive of all Infection terms for 2020.
• Two new MeSH headings are added as children to category Infections [C01]:
  • Vaccine-Preventable Diseases
  • Vector Borne Diseases

MeSH Category Cell Physiological Phenomena [G04] is updated.

• One new MeSH heading is added as a child to category Cell Death [G04.146] and six new headings are added as grandchildren:
  • Regulated Cell Death
    • Autophagic Cell Death
    • Ferroptosis
    • Immunogenic Cell Death
    • Mitochondrial Transmembrane Permeability-Driven Necrosis
    • Necroptosis
    • Parthanatos
• Four new MeSH headings and one MeSH heading with a preferred term change are added as children to category Autophagy [G04.011]:
  • Autophagic Cell Death
    Note: This new MeSH heading is in two tree positions as a child to Autophagy and Regulated Cell Death.
  • Chaperone-Mediated Autophagy
  • Macroautophagy
  • Microautophagy
  • Mitophagy
    Note: In 2020, the preferred term for Mitochondrial Degradation is replaced by Mitophagy. This MeSH heading is in two tree positions as a child to Autophagy and Mitochondrial Turnover [G04.599].
• Autophagy is removed from categories Cell Death [G04.146] and Phagocytosis [G04.417.350] and repositioned as a child to Cell Physiological Phenomena [G04].
• Necrosis and its children are removed from Cell Physiological Phenomena [G04.146.638] and retain their positions in Pathological Conditions, Signs and Symptoms [C23.550.717].

MeSH Special Projects

Several special projects resulted in the following new 2020 MeSH headings:

Food related headings:

• Animal Proteins, Dietary
• Artificially Sweetened Beverages
• Edible Insects
• Pork Meat
• Salads
• Sugar-Sweetened Beverages

Health Services headings:

• Military Health Services
• School Mental Health Services
• Veterans Health Services

Person headings:

• Atomic Bomb Survivors
• Indigenous Peoples
• Intersex Persons
• Para-Athletes

Psychiatry and Psychology related headings:

• Avoidant Restrictive Food Intake Disorder
• Body Dissatisfaction
• Body Integrity Identity Disorder
• Diabulimia
• Emotional Regulation
• Food Fussiness with an entry term of Picky Eating
• Psychological Distress
• Suicide, Completed

Toxicity headings:

• Myotoxicity
• Ototoxicity

Non-human primate terminology is expanded to include 148 new SCRs and 11 new MeSH headings:

• Alouatta caraya
• Ateles geoffroyi
• Callicebus
• Cebus capucinus
• Galagidae
• Indriidae
• Macaca arctoides
• Macaca fuscata
• Presbytini
• Sapajus
• Sapajus apella

18,403 new SCRs for bacteria are available. A cross-divisional project was undertaken at NLM to insert these terms from the NCBI Taxonomy into the MeSH vocabulary.

Two MeSH concepts merged into one:

Cascara merged into Rhamnus. Cascara is not retained as entry term. Cascara Sagrada and Sacred Bark are retained as entry terms to Rhamnus. Casanthranol is retained as entry term to Emodin.

Coniferophyta merged into Tracheophyta. Coniferophyta is retained as an entry term.

Punicaceae merged into Lythraceae. Punicaceae is retained as an entry term.

Taxodiaceae merged into Cupressaceae. Taxodiaceae is retained as an entry term.

Do Not Confuse:

Case Reports with Single-Case Studies as Topic, which are trials that consider an individual patient as the sole unit of observation in a study investigating the efficacy or side-effects of different interventions to determine the optimal intervention for an individual patient using objective data-driven criteria. Also note that Single-Case Studies as Topic is used for indexing articles on the general design, methodology, etc. for Single Case Trials.

Food Fussiness with Avoidant Restrictive Food Intake Disorder, which is an eating or feeding disturbance that manifests as persistent failure to meet nutritional needs leading to low weight, nutritional deficiency, dependence on supplemental feedings, and/or psychosocial functioning.

Rumination, Cognitive with Rumination Syndrome, which is a gastrointestinal disorder.

Stress, Psychological with Psychological Distress, which is an negative emotional state characterized by physical and/or emotional discomfort, pain, or anguish.

Undiagnosed Diseases with Missed Diagnosis, which is a failure to identify or diagnose a medical condition at the time a health professional is acquainted with the symptoms.

Other Changes

In addition to changes and deletions of MeSH terms on MEDLINE citations, YEP includes other adjustments to reflect 2020 MeSH vocabulary and enhance search retrieval. These follow-on adjustments are largely to add additional MeSH headings or Supplementary Concept Record Names to citations in order to help searchers refine retrieval. In some cases, the changes clarify areas where a single concept existed before but is now represented by two or more specific concepts.

Entry Combination Revisions

This year during YEP, NLM will again retrospectively replace certain MeSH heading/subheading combinations, known as Entry Combinations, with the new pre-coordinated MeSH heading. If you get no retrieval for a MeSH heading/subheading combination check the heading in the 2020 MeSH Browser to see if the Entry Combination information indicates a different term.

There are four new Entry Combinations for 2020.

Previous MeSH Heading/Subheading (Entry Combination)	Replaced-by Heading for 2020
Phosphatidylinositol 3-Kinase/antagonists & inhibitors	Phosphoinositide-3 Kinase Inhibitors
Mandibular Nerve/injuries	Mandibular Nerve Injuries
Radio Waves/therapeutic use	Radiofrequency Therapy
Tumor Necrosis Factors/antagonists & inhibitors	Tumor Necrosis Factor Inhibitors

Other News:

Data Distribution Notes

There is no change to the PubMed DTD for 2020. The DTD dated 010119 is still valid.

Because there are no changes to the PubMed DTD, NLM will not create new sample data for 2020.

More information and announcements can be found at Download MEDLINE/PubMed Data.

New Databank Sources

During 2019, NLM added the following to the list of Databank Sources that may be carried in MEDLINE citations:

• Japanese Registry of Clinical Trials (jRCT)
• Lebanese Clinical Trials Registry (LBCTR), which is one of the WHO Clinical Trial Primary Registries