*3.5. Subject Categories and Journals Found using Scopus*

The frequency of publications by each thematic area was acquired from the Scopus database. In Figure 8, the distribution of the main thematic areas is represented. This figure shows that the area with the highest percentage of documents was medicine (50.7%), followed by social sciences (28.9%), computer sciences (19.2%), and psychology (10%). Areas such as agricultural and biological sciences (1.3%); engineering (1.6%); or pharmacology, toxicology, and pharmaceutics (1.4%) were less common in the database. The "other" (5.9%) category represents unspecified areas.

**Figure 8.** Distribution of scientific productions according to the main thematic areas.

These results show the two main thematic areas—medicine and social sciences (Table 4). Medicine is the central area of publication in the health field, as medicine is one of the most ancient areas of research [52]. The same could be said for social sciences, as social structures and social behavior have been studied for centuries [1].

**Table 4.** Main thematic areas concerning the total number of scientific productions found from the analysis.



**Table 4.** *Cont*.

The first quartile (Q1), Scimago Journal Rank (SJR), and Journal Citation Report (JCR) have been included in the table so as to present the importance and relevance of the major journals that have published more publications. These measures were chosen based on their quality and for being used worldwide in the scientific field. The quartiles are based on ranking each journal according to their subject, using the impact factor distribution the journal occupies for that subject category as a measure. In this sense, Q1 denotes the top 25% of the impact factor distribution. The Scimago Journal Rank measures the weighted citations received by the serial. Citation weighting depends on the subject field and the prestige of the citing serial. Finally, the Journal Citation Report is based on citations compiled from the Science Citation Index Expanded and the Social Sciences Citation Index [53].

The leading 11 journals that have published in this research field, and the number of publications in each according to the Scopus database, are shown in Table 5. As can be seen, most of the journals with the greatest number of documents published and the highest impact factors are from the United Kingdom (U.K.), Canada, and the United States (USA).



*IJERPH* **2019**, *16*, 4024
