by Cynthia M. Schmidt, M.D., M.L.S.
Published December 2015
Updated July 2019
You should complete the first, second, third, fourth, fifth, and sixth episodes of this tutorial miniseries before beginning this seventh episode.
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You run into Dr. Li, Sarah's family practitioner, in the cafeteria. Dr. Li asks you a few questions about dietary recommendations for obese, pregnant patients and then asks you if you would give a presentation to the Family Practice faculty and residents about dietary interventions for obese, pregnant patients. You agree to give the requested presentation.
You decide to do a PubMed search to review the literature published on the topic of dietary recommendations/therapy for obese pregnant women.
It would be hard to conduct a keyword search on the topic of dietary interventions for obese, pregnant women.
Why?
Because there are many types of dietary interventions, and an author does not have to use a form of the word "diet" when describing these interventions. An author might discuss -
restricted calorie intake,
vegetable-rich meals,
a weight control intervention
etc.
Fortunately, searches for articles about various dietary interventions are relatively easy to construct using Medical Subject Headings (MeSH).
Each article represented in MEDLINE is read by a human indexer who decides what topics are the focus of the article. The indexer then adds medical subject headings (MeSH) corresponding to each of these topics to the PubMed record for the article.
The searcher can look up MeSH corresponding to his/her interests and use these to search PubMed.
Why is MeSH searching helpful?
The tutorial will guide you through the steps involved in a MeSH search:
1. List search concepts
2. Determine which concepts should be represented by headings versus subheadings.
3. Look up headings using the MeSH database and add headings and/or subheadings to the "PubMed Search Builder."
4. Correct any problems with operators and parentheses
5. Run PubMed search.
6. Add keywords if needed.
7. Add filters.
8. Obtain full-text
Always begin a search by listing the major topics.
You want to see the research and review papers that have been written about diet therapy for obesity in pregnancy.
What are the major concepts in this search?
Did you list --
diet therapy
obesity
pregnancy
--as your major search topics?
In this search, two topics, are names of conditions/diseases --
Conditions/disease are always heading concepts.
-- concept may be represented by a subheading, or by a heading, or both.
When "diet therapy" is an important search concept, it's usually best to construct a search that requires either the presence of the "diet therapy" subheading OR the presence of the "diet therapy" heading (or a broader heading).
"Obesity/diet therapy"[Mesh]
The [Mesh] tag is used with headings or heading/subheading combinations, and stands for "medical subject heading."
Alternately, the "diet therapy" subheading could be added to the search without an associated heading (as a floating subheading)--
("Obesity"[Mesh]) AND "diet therapy" [Subheading]
In your search, a floating subheading may work better.
Because it's not certain whether the diet therapy subheading would be associated with the "obesity" or the "pregnancy" heading.
At this point you might plan to use the following in your search
But, at this point, you don't know how the actual headings for your concepts are worded.
To access PubMed and it's MeSH database:
One must use MeSH database to look up the actual heading for a concept. The MeSH database is just a list of subject headings (it's like a thesaurus or dictionary). It gives you the tools you need to find a the correct wording for one heading at a time and to add that heading to a PubMed search.
To find the heading for "pregnancy":
Now move on to the "obesity" heading.
Should you use AND, OR, or NOT to join the Pregnancy MeSH to the obesity MeSH?
You are planning to use a 'floating' "diet therapy" subheading.
But, what if you wanted to associate the diet therapy subheading with the obesity subheading?
In that case you would:
The answer is yes! A heading without subheadings will retrieve any combination of that heading with a subheading.
If you think about it, this is a bit like a broad heading retrieving narrower headings. In this case a general term is retrieving a specific aspect of the term.
As mentioned earlier, you need a search that look for either the "diet therapy" subheading OR the "diet therapy" (or a broader) heading:
Do you know what's included in the "Diet therapy" heading search?
To find out:
The broader heading, "Nutrition Therapy", might retrieve some additional relevant records.
Because PubMed explodes headings by default, a search using the "Nutrition Therapy" heading will retrieve records indexed with the "Nutrition Therapy" heading, and all the narrower headings (including "Diet Therapy" and its narrower headings).
Did you use -- OR -- to join the "diet therapy"[subheading] to "nutriton therapy"[mesh]?
If so, good job!
If not, correct your search.
Look over the whole search strategy currently in the PubMed Search Builder.
Are any changes in the AND, or ORs or parentheses needed?
In the search shown in the figure, there are no problems with the ANDs and ORs. However, there is a problem with the parentheses.
Always be careful to check any OR'd together terms to be sure they're enclosed in a set of parentheses. In this search, the two "diet therapy"-related terms should be OR'd together and enclosed in parentheses.
("diet therapy"[subheading] OR "Nutrition Therapy"[mesh])
The OR between the terms tells PubMed to find records containing either one term OR the other.
The parentheses tell PubMed to do the operations inside the parentheses first and to treat the results as a set.
The PubMed search engine will retrieve records that are retrieved by either the "diet therapy"[subheading] or the "Nutrition Therapy"[MeSH]. Then it will read from left to right. It will find records that have both a pregnancy heading and an obesity heading. Then PubMed will find the subset of these records that also are in the set of results previously retrieved for ("diet therapy"[subheading] OR "Nutrition Therapy"[mesh]) .
((("pregnancy"[mesh]) AND "Obesity"[mesh]) AND ("diet therapy"[subheading]) OR "Nutrition Therapy"[mesh])
--PubMed would find the set of records retrieved by "pregnancy"[mesh] AND "obesity"[mesh] AND "diet therapy"[subheading] and would then include (OR in) all the records that are retrieved by the "nutrition therapy"[MeSH] whether or not they had anything to do with pregnancy or obesity.
If all the unneeded parentheses and the errant parentheses are removed from the search it will look as shown below:
"Pregnancy"[mesh] AND "Obesity"[mesh] AND ("diet therapy"[subheading] OR "Nutrition Therapy"[mesh])
Click the "Search PubMed" button under the search builder.
How many results did your search retrieve? As of, July 2019, this search retrieved over 360 results.
If you are seeing a lower number of results, it's possible that you applied a filter to a PubMed search you performed earlier. Is there an "i" icon above the search results with information about "Filters activated"? If article type filters are active, click the "Clear all" link to see the results of your search without the article type filter.
At this point, keywords could be added if you had any search concept/s that had no corresponding medical subject heading/s.
Any desired filters could also be added.
As you look over the first page or two of results, you notice several articles dealing with the efficacy of dietary interventions in obese pregnant women. One is specifically focused on individual meetings with dieticians
Click on the title of the article entitled "Effect of individual dietetic intervention ...." (#20 at the time of this tutorial's last update).
You will see the full-text buttons on the right-hand side of the page.
Since there is no "Free" or "Open Access" button, click on the "GetIt@UNMC" button ( Warning: A new window will open and you will have to click back to the tutorial "UNMC Library Tutorial" window/tab to see the tutorial instructions)
This particular journal, Australian and New Zealand Journal of Obstetrics and Gynaecology(ANZOG), shows the html version of the full-text immediately.
Like many journals, ANZOG, provides the PDF icon/link/button in different places depending on the size of the screen. ANZOG gives large screen users a "PDF" icon/link above the article's abstract. Small screen users have to use an "About" menu above the journal's title to find the "PDF" icon/link.
Is the following statement true or false:
An intervention focused on obese pregnant women that was delivered during a series of individual meetings with a dietitian resulted in significantly lower levels of macrosomia and caesarean delivery among study participants compared to obese populations in comparable studies.
You may want to save a search composed of the important nutrition headings for future use. If not, you can skip this screen and the next three screens.
The following search is composed of the most important terms in the MeSH database for nutrition concepts:
("diet therapy" [Subheading] OR "Nutrition Therapy"[Mesh] OR "Feeding Methods"[Mesh] OR "Vitamins" [Pharmacological Action] OR "Food"[Mesh] OR "Nutrition Disorders"[Mesh] OR "Nutritional Physiological Phenomena"[Mesh] OR "Trace Elements" [Pharmacological Action] OR "Body Weight"[Mesh])
You can create a personal PubMed (My NCBI) account and save this search for instant access at a later date. When you use the search in the future you can remove irrelevant terms.
To do so:
If you don't complete the steps below, you will not have "GetIt@UNMC" buttons in your search results while you are logged into My NCBI:
University of Nebraska Medical Center
-- in the search box that appears, and hit the "Search" button.
To see and/or use your saved search:
Which of the search types makes it possible to search for all MEDLINE records concerning any bone disease with a single search term while simultaneously ensuring that all records retrieved will actually focus some attention on a bone disease?
One of your colleagues has run a search for --
("Toxoplasmosis"[Mesh]) AND "Neurocognitive Disorders"[Mesh]
Part of the MeSH tree that includes "Neurocognitive Disorders" is shown above this question box.
Which of the PubMed records described below would be retrieved by your colleague's search?
PubMed
-- combination is often useful when working on nutrition-related searches.
Link to the very brief final episode:
http://list.unmc.edu/gots/tutorial/sb8n