The rWikiPathways package in bioconductor lets you search the database in a few different ways. Like the comments above, exactly how you define a "diabetes pathway" is up to you. For example, you can search for any pathway that mentions "diabetes" anywhere in the title or description and then filter for the human set:
library(rWikiPathways)
db.pathways <- findPathwaysByText('diabetes')
human.db.pathways <- db.pathways %>%
dplyr::filter(species == "Homo sapiens")
human.db.pathways$name
There were 4 that popped up when I ran this snippet:
[1] "Type II diabetes mellitus"
[2] "Insulin signalling in human adipocytes (diabetic condition)"
[3] "Polyol Pathway"
[4] "16p11.2 distal deletion syndrome"
You can retrieve the WPID identifiers and other info from the same returned data frame.
Alternatively, you can seach by your favorite diabetes gene, e.g., INSR:
findPathwaysByXref('INSR','H')
This returns 27 human pathways! The bioconductor package includes additional vignettes for other common use cases.
This is probably the best you can do with databases. But nothing is really going to beat either a) Learning enough about the biology of diabetes that you know if the pathways are involved or b) showing your list of pathways to someone who has an indepth knowledge of Diabetes biology.
What is the difference between KEGG diabetes here: https://www.gsea-msigdb.org/gsea/msigdb/cards/KEGG_TYPE_II_DIABETES_MELLITUS.html and KEGG diabetes here: https://www.kegg.jp/dbget-bin/www_bget?ds:H00409 ??????
In the first link: I couldn't get the pathways itself, just gene set can be obtained, while in the second link: I can get the pathways itself. So which link do you think I can use?